Case studies prepared by IOP in partnership with EPSRC and STFC | June 2013
Physics: transforming lives
The Institute of Physics
is a leading scientific society. We
are a charitable organisation with a
worldwide membership of more than
50,000, working together to advance
physics education, research and application.
We engage with policymakers and the
general public to develop awareness and
understanding of the value of physics and,
through IOP Publishing, we are world
leaders in professional scientific
communications.
Foreword
There are many ways of describing the beauty
and elegance of physics and the incredible
value that it has delivered for society, everpresent in the everyday things around us.
Physics continues to help us unlock the
mysteries of our universe and the world we live
in, and is one of our most powerful enablers of
innovation and discovery.
Physics research explores and expands the boundaries of our knowledge.
In July 2012, researchers at the Large Hadron Collider at CERN moved
us one step closer to unlocking the mysteries of what our universe
is made of when they announced the discovery of a Higgs boson –
thought to be responsible for giving mass to everything in our universe.
But physics is also central to everyday life. Physicists are actively
collaborating with other researchers and applying their knowledge and
technical skills in response to the major challenges of our time, such
as sustainable sources of future energy, understanding our changing
climate and global food security. Their efforts can also be found at
the heart of the technologies we use each day, such as computers,
smartphones and GPS devices, which would not exist without physics
research. Physics also helps improve the quality of our lives through
the use of high-tech equipment, such as particle accelerators, which
find important application in healthcare, playing such a key role in
improving the diagnosis and treatment of diseases like cancer.
At the Institute of Physics, one of our objectives is to promote the
fundamental importance of the discipline by showcasing how advances
made by physicists in both academia and industry continue to impact
upon all our lives. Physics: transforming lives is a series of short case
studies reviewing how innovations as powerful as magnetic-resonance
imaging, have emerged from studies in basic physics and become
routine technologies. The booklet also provides some clues as to how
things may develop over the next few years, coupled with numerous facts
and figures which will be useful to Government and in the classroom.
Professor Paul Hardaker
Chief Executive
The Institute of Physics
June 2013 Physics: transforming lives
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Contents
The space industry
Liquid-crystal displays
Plastic electronics
Radio-frequency identification tags
Optical fibres
Cancer treatment
Physics and DNA
Energy efficiency
Detecting explosives and pollutants
Data storage
Satellite timing and navigation
5
9
13
19
23
29
39
45
51
55
59
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Physicists are actively
engaged in helping to solve
everyday problems by working
collaboratively with other
researchers and applying
their knowledge and technical
skills in response to the major
challenges of our time, such as
environmental change brought
about by our soaring demand
for energy from finite resources.
Their efforts can be found in
everyday technology, such as
smartphones and GPS devices,
which would not exist today
without physics research.
4 I IOP Institute of Physics
The space industry
A vibrant space economy enables satellites to
provide a welcome boost during a downturn.
The science
Almost the entire UK space industry stems
from physics research, which underpins
everything from the design of the satellites
to the trajectory at which rockets are
launched, to the tweaks that must be made
to keep satellites in orbit and pointing in the
right direction.
Spacecraft orbiting the Earth – or en route to their designed orbit –
must traverse a region that is awash with charged particles that can
damage the sensitive electronics mounted on satellites. Physicists must
develop materials that are inured to this harsh environment in order to
keep satellites functioning for months and years. Satellites also need
electrical power to function, and physicists devise ever cleverer ways
to harness the Sun’s rays for this purpose – although fuel cells and
nuclear power have also been used.
Rocket science
The Harwell Oxford Space Cluster is the national innovation hub for space
technology and new satellite applications and services. The hub was
founded on STFC’s capabilities in its Rutherford Appleton Laboratory
(RAL) Space department and now includes the European Space Agency’s
UK office, their Business Incubation Centre, and the Satellite Applications
Catapult Centre, which is supported by the Technology Strategy Board.
What physics does it rely on?
−− Classical mechanics
−− Materials science
−− Magnetohydrodynamics
−− Condensed-matter physics
Impact
The space industry has prospered in recent times despite the nation’s
limited finances. Over the past decade it has grown to become a
medium-sized industry in the UK, directly employing 30,000 people and
reporting a turnover of £9.1 bn in the year 2010/11. The vast majority
of this turnover, 89% or £8.2 bn, comes from the industry’s downstream
sector; for example, satellite communications, satellite broadcasting,
satellite-navigation, and the like. Since 2008/09, the space industry
has grown by 15.6%, an average annual growth rate of 7.5%.
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The space industry
Applications
Over the past few decades, the space industry has helped to spur
globalisation by cutting the cost of communication and enabling ease of
contact. Satellites have revolutionised telecommunications, broadcasting
and internet access, all of which have increased overall productivity.
Demand for ubiquitous access to social networking is creating new
opportunities for satellite broadcasting and communications. Other
applications include the provision of satellite-navigation systems to
vehicle drivers, and communications technologies to the military.
Broadcasting
In the UK satellite broadcasting makes up the largest proportion of
the turnover generated by the space industry’s dominant downstream
sector, about 70% between 2008/09 and 2010/11. Through this share
of the downstream sector, satellite broadcasting generated a turnover
of about £5.8 bn in 2010/11. More than a third of homes in the UK
now have satellite television feeds. Satellite broadcasting is cheaper to
deliver to remote areas than cable, and reaches places that terrestrial
broadcasting would struggle to serve. Not only is satellite television
popular with subscribers, it is also used by broadcasters: almost all
television goes via a satellite at least once on its way to homes, whether
or not the viewer is explicitly paying for satellite television or not.
Communications and geopositioning
Satellite communications, including telephony between remote
locations, satellite-navigation systems, air traffic control systems and
communications to ships, account for 13% of the revenue generated
by the UK space industry. Satellites enable people to communicate
over long distances where terrestrial broadcasting or a direct cable
connection are impractical. Satellites cover a far greater area than
terrestrial systems and enable higher bandwidths to be used, so that
hundreds of thousands of conversations, emails and internet requests
1957 The Soviet Union
launches Sputnik, the
first artificial satellite to
orbit the Earth.
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1961 Britain launches
its first satellite,
Ariel 1, to study the
ionosphere, the upper
atmosphere at the edge
of space.
1981 The University of
Surrey launches its first
satellite with the help
of NASA, the American
space agency.
2008 Surrey Satellite
Technology, a spin-off
company from the
University of Surrey,
is sold to Astrium,
a subsidiary of the
Franco-German
aerospace giant EADS,
for a reported £50 m.
Over the past decade, the space industry directly
employed 30,000 people and reported a turnover of
£9.1 bn in the year 2010/11.
can be handled simultaneously. Three-fifths of people living in the UK
now own a smartphone, and half of drivers use satellite-navigation,
further increasing the traffic that satellites handle.
Earth observation
Satellites can be used to gather information about the planet. This can
be used to develop scientists’ understanding of climate change, which
is widely expected to cost the world economy up to three per cent of
its global output by 2050. It is also used to provide weather forecasts,
which enable energy companies to stock up on fuel prior to a cold
snap and farmers to plan their work. Satellites can monitor natural
disasters, such as floods, hurricanes, earthquakes and tsunamis, and
enable people to devise how best to respond.
Military
British satellites provide secure and reliable communications that
can provide high data rates to small and remote units typically used
in an initial response to disasters and rescue operations, as well as
for military operations. Four military communications satellites with
anti-jamming antenna orbit the Earth and can be steered to focus onto
particular regions of the world as needed. The satellites were designed
and built by UK Astrium, which operates the constellation on behalf of
the UK Ministry of Defence.
Manufacturing and operating systems
Just over 10% of the revenues from the space industry come from
building spacecraft and the operating systems needed to control
them from the ground. Most satellites are used for broadcasting and
communications but British scientists also build satellites for scientific
purposes and for foreign customers, including Algeria, China, Chile,
Germany, Malaysia, South Korea, Thailand and the United States.
Astrium UK recently won a £260 m contract to build a spacecraft that
will orbit the Sun for the European Space Agency; a second British
2009 Despite the
economic recession,
Britain’s space
industry maintains
an average annual
growth rate of 7.5%.
2010 The coalition
government launches
the UK Space Agency.
2030 Britain aims
to have 10% of the
international market
share of space, up from
six per cent in 2009.
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The space industry
company that it recently acquired,
Surrey Satellite Technology, has a
contract worth about £190 m
to build satellite-navigation
systems for the European Union’s
network of satellites, which
will provide an independent
alternative to the US Global
Positioning System and Russia’s
GLONASS. In 2011 DMC Imaging
International, a subsidiary of
Surrey Satellite Technology, won
a £110 m contract to supply a
Beijing company with images
from its satellites, which
accounted for about 10% of the
UK’s high-technology exports to
China that year.
Future
Britain’s international market
share in space was estimated to
be six per cent in 2009 but the
UK Space Agency, launched in
2010, aims to boost it to 10%
by 2030, which would generate
a turnover of £40 bn. The UK
has more than a hundred small
space firms each with turnovers
of less than £1 m, some of which
are expected to grow significantly
or to be bought by bigger
organisations. The Organisation
for Economic Co-operation
and Development (OECD)
suggests that satellites will
power the growth in availability
of broadband in rural areas, the
delivery of high-definition and
3D television and improved
air-traffic management within
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the next five years. Automatic
identification systems via satellite
will allow countries to monitor
shipping along their coastlines,
enabling the closer monitoring
of potential environmental and
security problems.
Facts and figures
3.5
jobs are generated
elsewhere for every job created in
the space industry
£8.2
bn value-added
contribution to UK GDP in
2010/11 through the multiplier
impact
+ potential
£40
bn
turnover boost to the sector
by 2030
+
100,000
new jobs by 2030
+ tonnes of carbon40
m
dioxide emissions a year could be
saved by satellite internet
Liquid-crystal displays
Physics research is revolutionising
consumer electronics.
The science
Liquid crystals flow like a fluid
but have molecules that can be
oriented in a crystal-like way.
A thin film of the material can
be sandwiched between two
glass slides that are coated
with transparent electrodes and
connected to an electrical power
source, as the optical properties
of the film can be controlled
by a voltage. When the power
is switched on, the molecules line up in one direction; when it is
switched off, they flip to another arrangement. A liquid-crystal display
(LCD) is typically made using thousands of electrodes, each of which
is controlled individually. Detailed and rapidly moving images can be
created by switching the individual elements on and off.
A truly international venture
LCDs were first developed in the US but British scientists invented the
first stable liquid crystals and the technologies needed to use LCDs
for televisions, and licensed their expertise worldwide. In recent years,
South Korea has become dominant at manufacturing the devices.
What physics does it rely on?
−− Condensed-matter physics
−− Optical physics
−− Materials physics
−− Physical chemistry
−− Mathematics
Impact
LCDs were first developed for pocket calculators and digital
wristwatches in the 1970s but the global market for flat-panel displays
is now worth about £100 bn, of which LCDs form the largest segment.
Despite the economic downturn, sales are expected to grow modestly
in 2013. Over the years, the technology has generated substantial
revenues for the UK, mostly through royalty income from patents.
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Liquid-crystal displays
Applications
LCDs can be made almost any size, from small screens just centimetres
across to large ones several metres across. They are used in devices such
as televisions, computer monitors, smartphones, handheld video games,
cameras and satellite-navigation systems.
Televisions
Almost all televisions now use LCDs to produce images. The sets are
thinner and lighter than the previous technology, enabling people to fit
bigger screens into their homes. Most televisions bought in the UK are
made abroad, but Cello Electronics, which is based in Bishop Auckland in
the north-east of England, manufactures devices for sale under retailers’
own brands both at home and elsewhere. It has invested heavily in
research and development to bring new technology to the UK market at
the same time or earlier than many of its Japanese and South Korean
competitors. The company recently opened a new factory where it is
expanding production for sales in Europe, particularly Germany.
Staff working at Sharp Laboratories Europe, based in Oxford, also
develop LCDs for new applications. These include a screen that can
display different content to viewers, enabling a couple equipped with
two sets of headphones to enjoy two different television programmes
on the same screen simultaneously.
Smartphone screens
All of Apple’s iPhones and many other smartphones use LCDs. In 2013,
Russian company Yota Devices demonstrated a dual-screen phone with
an LCD that allows people to watch high-definition television or to flick
through detailed photographs on their smartphones and an electronic
paper display that enables them to show electronic tickets and
boarding passes – even after they have exhausted the device’s battery.
1889 Physicist Otto
Lehmann uses a
polarising microscope
to study liquid crystals
and recognises that
they represent a new
state of matter.
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1936 The first
patent to claim a
potential display
application of liquid
crystals is granted
to the UK Marconi
Wireless Telegraph.
1972 George Gray
and Ken Harrison of
the University of Hull
and Peter Raynes of
the Royal Signals and
Radar Establishment in
Malvern invent the first
liquid crystals suitable
for mass production.
1978 Cyril Hilsum of
the Royal Signals and
Radar Establishment
and colleagues at the
University of Dundee
invent the technology
needed for the liquidcrystal picture-element
switches now used in
all televisions.
Over the years, LCD technology has generated
substantial revenues for the UK, mostly through royalty
income from patents.
Games consoles
Handheld video games systems, such as the PlayStation Portable
and the various devices produced by Nintendo, use LCDs in their
screens. In 2011 Nintendo launched its glasses-free, 3D games
console, the Nintendo 3DS, and sold 113,000 of the devices in the
UK in just two days.
Electronic paper
LCDs can be used to make electronic paper, which looks like ordinary
paper but which can be altered centrally to enable consistent
information to be displayed across a wide area. ZBD Solutions, based
in Ascot, supplies electronic paper to customers throughout Europe
and has recently signed a deal with the John Lewis department store
in Exeter to provide it with displays that customers can use to see the
prices of products on the shelves and to discover more information
about them. The company emerged in 2000 from the same British
laboratories where the first liquid crystals suitable for mass production
were developed.
Future
The first commercially available televisions to use LCDs to produce 3D
images to viewers wearing special glasses went on sale in the UK in
2010. Since then, companies have developed devices that produce
3D effects without the need to wear special eyewear. High-definition
televisions that use LCDs are also expected to be popular with viewers.
The BBC has already begun to film its first wildlife documentaries to
make use of the technology.
1985 Seiko
Epson unveils the
first commercial
colour television
to use an LCD.
2007 Worldwide sales
of LCD televisions
outstrip cathode-ray
tubes for the first time.
2013 At the annual
Consumer Electronics
Show in Las Vegas,
where electronics
manufacturers show
off new technologies,
a smartphone with
an LCD wins a best-inshow award.
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Liquid-crystal displays
Key facts and figures
+ of televisions use
90%
LCDs and screens are 10% bigger
than three years ago
4x
the resolution of current
high-definition television screens
— these will go on sale in 2013
+ LCD televisions
260
m
are predicted to be sold
worldwide in 2015
12 mths
to recoup
the cost of switching to electronic
paper displays in shops
+ in UK
£100
m
royalties from licensing its liquidcrystal inventions
Zero
smartphones
and other mobile technology
would not have been
possible without LCDs
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Sharp Laboratories
Europe develop LCD
applications including
a screen that can
display different
content to viewers,
enabling a couple to
enjoy two different
television programmes
on the same screen
simultaneously.
Plastic electronics
A new technology promises light-weight
and flexible electronic devices.
The science
Semiconductors are the foundation of
modern electronics. Traditional electronics
are reliant on inorganic semiconductors, for
example, silicon and gallium nitride alloys
with varying fractions of indium. By contrast,
modern organic electronics, used widely
in smartphone displays, work with carbonbased semiconducting (i.e. conjugated)
polymers and small molecules.
Carbon-containing “organic” molecules that sublime on heating can
be laid down using thermal vacuum deposition techniques similar to
those used to create thin films of metal on many surfaces. Alternatively,
solution-based processes including printing techniques analogous
to those employed in the traditional printing industry can be used
for those molecules that dissolve in suitable solvents. Long-chain
molecules, or plastics, generally fall into the latter category.
Illuminating work
The UK is at the forefront of discoveries in plastic electronics: in 1989
physicists at the University of Cambridge discovered that certain
plastics could be made to generate light when wired up to an electrical
power source. The nation has created a network of five centres of
excellence in plastic electronics to exploit this lead. More than 20
universities and dozens of small companies and multinationals now
develop the technologies in the UK.
What physics does it rely on?
−− Molecular physics
−− Materials processing
−− Semiconductor physics
−− Optics
−− Printing and graphics science
Plastic can also be made to emit light by sandwiching it between two
electrodes, one of which injects electrons and the other “holes”. When
these meet, light is generated.
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Plastic electronics
Impact
Carbon-based electronics was worth an estimated $10 bn worldwide
in 2012, most of which was in display technologies. IDTechEx, a market
analyst, suggests that by 2022 the total market will be worth more
than $60 bn, rising to $350 bn by 2032. In 10 years’ time, it predicts
that about a third of carbon-based electronics will be produced on
flexible surfaces. More than 3000 organisations are pursuing various
versions of the technology, including printing, electronics, materials and
packaging companies.
Applications
Plastic is widely used because it is cheap and easy to make and
handle. Plastic electronics can create new sources of light for homes
and offices, generate electricity from the most abundant source
of power on the planet – sunlight – and be used to make cheap,
disposable medical devices. The most popular electronic display
screens currently use vacuum deposited carbon-based molecules, but
flexible printed displays could soon become the dominant technology.
Lighting
Light sources made from carbon-based electronics offer an
alternative, environmentally friendly way to produce light. They can
be used to construct walls or screens that light up. The panels can
also be transparent, allowing windows to transmit natural light by
day and to generate a soft glow by night. As a demonstration of the
technology, General Electric has incorporated printed electronics
into a set of protective clothing for fire fighters that shines brightly in
the dark. The devices could even form part of soft furnishings such
as curtains. Several European companies, including OSRAM and
Philips, already sell desk lamps that use small-molecule electronics
to generate light and Thorn Lighting in the UK is working with
Cambridge Display Technology to develop lamps that use printed
1970s Physicists and
chemists discover
that, instead of acting
as insulators, some
plastics can be made
to conduct electricity.
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1989 The physicists
Donal Bradley, Jeremy
Burroughes and
Sir Richard Friend
at the University of
Cambridge succeed
in manipulating thin
sheets of plastic to
generate light.
1992 The same
physicists join with
colleagues to form
Cambridge Display
Technology, which is
sold in 2007 for a
reported $285 m.
2002 Printed
electronics feature in a
James Bond film, Die
Another Day; the Philips
shaver incorporates
them in its display.
Carbon-based electronics was worth an estimated
$10 bn worldwide in 2012, rising to $350 bn by 2032.
electronics. Almost every lighting company is engaged in research
and development of the technologies.
Solar power
Carbon-based solar panels offer certain advantages over traditional
devices. They are light-weight and rugged; they can be made to cover
large areas; they generate electricity even on gloomy days; and they
could be made cheaply. Five start-up companies have emerged in the
UK over the past five years to work on solar-energy generation including
the development of solar-powered lamps for use in poor communities
abroad that have no access to the electricity grid.
Many European companies are developing plastic electronics to build
solar cells that would be flexible and light-weight, and so fit onto roofs
easily. The solar cells can also be made visually transparent so that
they could be fitted over skylights. In principle, solar cells could be
printed directly onto windows, embedding the generation of electricity
from solar power in new homes.
Some manufacturers have begun to attach flexible plastic solar panels
to the outside of laptop bags, enabling the bag to recharge smaller
electrical items such as smartphones.
Medical devices
Plastic electronics are being used to develop portable, point-of-care
medical devices capable of achieving similar results to much more
expensive laboratory-based instruments. Molecular Vision, a spinout company from Imperial College London that is now part of the
Abingdon Health Group, has developed a lab-on-a-chip device that
combines a light source with a detector. It can test a single sample
of blood or urine to identify kidney disease or whether someone has
recently had a heart attack. The same technology could be used for
2009 The Department
for Business, Innovation
and Skills launches
the UK Strategy for
Plastic Electronics.
2012 Some 45
companies and more
than 20 universities
in the UK are engaged
in the research and
development of
plastic electronics.
2013 The most
successful products
yet to use carbonbased electronics
– the Samsung
Galaxy smartphones
– sell more than 100
million devices.
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Plastic electronics
veterinary testing, forensic
science and detecting
environmental pollution.
Screens and displays
Carbon-based light-emitting
devices are found in sleek, lightweight products such as some
of the latest smartphones, and
are a complementary technology
to LCDs. Samsung, for example,
uses them to display images on
the screens of its best-selling
devices, and LG Displays, another
South Korean company, is due
to begin mass production of
competitively priced televisions
that will use them in 2013. The
televisions will produce clearer
and faster-moving images than
many current devices and will
be lighter, thinner and more
energy-efficient than a number
of the flat-screen televisions
commonplace today. Cambridge
Display Technology and Seiko
Epson produced an ink jet printed
TV display prototype in 2003/04.
Additionally, Sony recently
unveiled its first television display
to use printed electronics. Many
companies now seek to switch
from printing onto glass to flexible
substrates that would bend easily
and, unlike their glass-substrate
counterparts, would not shatter
when dropped.
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Future
Plastic electronics might be
used to make smart packaging
for pharmaceuticals. Blister
packs of drugs could sound an
alarm to alert patients who had
failed to dispense their medicine
on schedule. The technology
might also be used to monitor
the condition of food inside its
packaging so that consumers did
not have to rely on the bestbefore date. Fashion designers
could join those who have already
experimented with fabrics that
emit coloured light and artists
who have created illuminated
designs. Plastic electronics could
become ubiquitous, creating a
wealth of intelligent but cheap
products that would change
business models and create new
sources of revenue.
Plastic electronics
The first television
display to use
printed electronics
was recently
unveiled. Many
companies now
seek to switch
from printing onto
glass to flexible
substrates that
bend easily and
do not shatter.
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Plastic electronics
Facts and figures
£70 m
has been invested
by the government in university
projects of direct relevance to
plastic electronics
$60
bn the predicted
global worth of plastic electronics
by 2022
$350
bn the
estimated worth of the global
carbon business by 2032
87%
of household carbondioxide emissions due to lighting
might be cut by 2050 if carbonbased electronics were used
18 I IOP Institute of Physics
Plastic electronics
might be used
to make smart
packaging for
pharmaceuticals.
Blister packs of drugs
could sound an alarm
to alert patients who
had failed to dispense
their medicine
on schedule. The
technology might also
be used to monitor
the condition of food
inside its packaging
so that consumers did
not have to rely on the
best-before date.
Radio-frequency identification tags
New uses of a Second World War technology
could revolutionise life in the internet age.
The science
A radio-frequency identity (RFID)
system consists of a small electronic
chip embedded in a plastic tag
or card, and a radio-frequency
transmitter and receiver, which
reads the chip, depending on the
type of tag, when it is anything
between a centimetre and 100 m
away. The reader transmits encoded
radio signals to interrogate the tag,
which provides the electronic chip with sufficient power to transmit
information to the reader using the reflected radio signal.
Through the ages
Many types of radio-frequency identification tags are the direct
descendants of devices that were attached to aircraft during the Second
World War. British-developed radar could detect aeroplanes but could
not identify friend from foe, so the Allies fitted their planes with tags that
broadcast their allegiance when interrogated from the ground.
What physics does it rely on?
−− Electromagnetism
−− Semiconductor physics
−− Materials science
Because the tag can use the energy transmitted by the reader to power
its response, it can work without batteries. Such RFID tags are relatively
small, light-weight and cheap to make.
Impact
The RFID market was worth $7.7 bn worldwide in 2012, according to
market analyst IDTechEx. Its figures show that the UK is currently the biggest
user of RFID technology in Europe. The technology has enabled train and
bus companies to introduce simpler fares and to cut journey times. This
makes public transport more appealing, helping to reduce greenhouse
gas emissions and paying off in other ways besides: the Cabinet Office
estimates that congestion, poor air quality, accidents and physical inactivity
all impose costs of around £10 bn every year in urban areas in the UK.
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Radio-frequency identification tags
Applications
The use of RFID tags is becoming ever more widespread. In recent years
UK companies have introduced them to create electronic tickets for
use on public transport, speed up shoppers queuing at tills, enhance
security checks at airports and track objects in the supply chain.
Public transport
Oyster cards containing RFID tags were introduced on the London
public transport network in 2003. Today some 55 million cards have
been issued and more than 80% of journeys made on public transport
in London involve using an Oyster card. The technology enables
computers installed in the gates of the Tube network to calculate the
correct fare to charge from 1.83 million possible journey permutations
in 200 milliseconds, speeding passenger flow through each station.
A third of the growth in public-transport use in London over the past
few years is due to fares reform that has been boosted by RFID chips,
according to a study by Peter White of the University of Westminster. He
suggests that the use of the technology to speed the boarding of buses
saves passengers as much time as the creation of bus lanes.
Bank cards
Retailers who want to accept contactless payments to cut queues are
installing devices to read the RFID tags that are being placed in bank
cards. Some five million contactless payment cards have been issued by
banks in the UK and the form of payment is now accepted by 100,000
retailers. Shoppers can simply tap their bank cards against an electronic
reader to pay for cheaper items such as lunch-hour sandwiches.
1873 James Clerk
Maxwell, a Scottish
theoretical physicist,
elaborates equations
that unify the
theories of electricity
and magnetism.
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1897 Morse code
signals transmitted
across Salisbury
Plain in England
using radio waves.
1935 British physicist
Sir Robert Alexander
Watson-Watt develops
radar that can be
used to detect
passing aeroplanes.
1940s Radio
transmitters that
identify an aeroplane
as friend or foe
when interrogated
by radar are placed
on aircraft during the
Second World War.
The RFID market was worth $7.7 bn worldwide in
2012. The UK is currently the biggest user of RFID
technology in Europe.
Passports
The technology is also being used for national security. The UK is one
of almost 100 countries that are introducing RFID tags in passports.
The chips will help border guards identify whether the person
seeking entry is the legitimate holder of the passport and could also
be used to automate the process, thereby cutting the queues at
immigration. The Identity and Passport Service currently issues more
than five million RFID-enabled passports every year and more than
half of those people who hold a passport now have the technology
embedded in their documents.
Logistics
The chips are used in logistics because they can be embedded in
products and tracked as they leave one factory and enter another.
The European Aerospace, Defence and Space Company, EADS, (which
owns aerospace companies Airbus, and Astrium, which build civilian
and military spacecraft), uses RFID tags to track components through
its manufacturing processes. For example, it uses RFID tags to monitor
construction of the Airbus A380, a double-decked aeroplane. Over the
past few years miniaturisation and mass production have made RFID
small and cheap enough to become more widespread. They are now
found within some supermarkets, where they are used to monitor stock.
1973 First patent
for a radio-frequency
identification device
intended for use in
collecting tolls is filed
in America.
2003 Smart
cards that use
radio-frequency
identification chips
are introduced to
the world’s largest
public-transport
system in London.
2012 Some 80% of
all public-transport
journeys in London
are made using
Oyster cards and the
scheme is credited
with promoting the
Tube and bus network.
June 2013 Physics: transforming lives
I 21
Radio-frequency identification tags
Future
Some hospitals are piloting
the use of RFID technology to
enable staff to know the precise
location of a doctor who is
on call and to link electronic
records to each patient. Others
are developing it to help monitor
the health of people who are
elderly and housebound. The
“internet of things” envisages a
hugely interactive world in which
machines communicate with one
another via the internet. Sensors
attached to a carton of milk
could detect when it was almost
empty and instruct the fridge
to order more supplies to be
delivered from the supermarket,
for example. RFID tags would be
fundamental to such a world.
McKinsey, a consultancy, argues
that such technologies would
create information networks that
produce new business models,
improve business processes and
reduce costs and risks.
22 I IOP Institute of Physics
Facts and figures
$26
bn the projected
value of the RFID market by 2022
55
million Oyster cards have
been issued by Transport for
London since 2003
30%
rise in the number
of bus journeys made in London
since 2003
4 bn
RFID tags were sold
in 2012. More than 30 million
British passports use the
technology
Optical fibres
Light-carrying glass fibres have transformed
communications and medicine.
The science
Optical fibres are fine threads
of glass, comprising a core and
cladding that are approximately
the same width as human hair,
which can transmit light over long
distances. They can be used to
transmit information as pulses of
light that travel down the fibres, with
little loss of signal compared with
copper wires. Cables containing
hundreds of optical fibres are robust enough to be laid on the ocean
floor, connecting continents as never before and revolutionising
telecommunications networks.
How do optical fibres work?
Optical fibres comprise a thin glass core through which the light
travels, coated in a second glass layer that reflects the light back and
guides it down the core. Because the optical fibres are flexible, the light
they transmit does not have to travel in straight lines and can be sent
along a curved path.
When used in telecommunications, the individual fibres in a cable
can carry many channels, each using a different wavelength of light.
Typically each channel transmits information at a rate of 10 or 40
gigabits per second, but rates of 270 gigabits per second have been
achieved – equivalent to 350 high-definition movies sent in one
second. As well as many channels per fibre, each cable can contain up
to 1000 fibres.
1887 Sir Charles
Vernon Boys uses
quartz fibres
for mechanical
measurements.
1928 John Logie
Baird, inventor of
the television, files
the first patent
demonstrating the
fibre-optic principle.
1952 Harold
Hopkins and
Narinder Kapany
of Imperial College
London create first
endoscope.
1961 Elias Snitzer
and Will Hicks at
American Optics fire
a laser beam through
a fine glass fibre.
June 2013 Physics: transforming lives
I 23
Optical fibres
What physics does it rely on?
−− Optics
−− Optoelectronics
−− Lasers
−− Photonics
Impact
The impact of optical fibres is hard to overstate. They have revolutionised
telecommunications, transmitting more information over greater distances
than could ever be achieved with copper wires, enabling the spread of
broadband networks and the many services that depend on them. The
world market for fibre-optic components alone is expected to reach
$31 bn by 2015. In 2011, 217 million kilometres of optical fibre were
produced globally – most of it for optical communications cables – and
the market is doubling each year.
Physicists in the UK were key contributors in the development of
optical-fibre technology. The UK remains a world leader in innovative
fibre-optics research and also maintains a strong manufacturing base,
with plants in Wales and Southampton.
Without optical-fibre cables enabling broadband communications, the
internet as we know it today would not be possible. Download services
such as iTunes and movies-on-demand require the large data-carrying
capacity that optical fibres provide. Around 70 per cent of UK homes
now have a fixed broadband connection, which is now a vital part of
everyday life underpinning the UK digital economy.
Optical fibres have also transformed medicine by enabling laparoscopic
procedures to minimise both the pain and healing time compared
with conventional surgery, and leave much smaller scars. Patients are
often discharged the same day, compared with up to a week in hospital
for those undergoing traditional surgery, saving time and money for
1966 Sir Charles Kao
and George Hockham
of STC Laboratories in
Harlow propose the
transfer of information
over glass fibres.
24 I IOP Institute of Physics
1966 The British
Post Office Research
Laboratories
begin fibre-optic
communications
research.
1970 US researchers
demonstrate glass
fibres can transmit
65,000 times more
information than
copper wires.
1977 Television signals
are transmitted using
optical fibres.
Physicists in the UK were key contributors in the
development of optical-fibre technology. Without
optical-fibre cables enabling broadband
communications, the internet as we know it today
would not be possible.
the NHS. There are dozens of laparoscopic procedures; one of the
most common is the gall-bladder operation, over 60,000 of which are
currently performed in the UK each year.
Applications
Telecommunications
Optical fibres cover the globe, connecting continents through
submarine cables. These are the backbone of the internet and
all telecommunications networks. Optical fibres are able to carry
many thousands of times more information than copper wires. They
provide the large bandwidth required for today’s internet, including
downloading music and high-definition videos, via services such as
iTunes and Netflix.
Optical fibres are ideally suited to undersea cables because they can
transmit information with little loss of signal compared with copper
wires. This allows distances of 50–100 km between the expensive
“repeaters” needed to boost the signal. The invention of the erbiumdoped fibre amplifier in 1987 by physicists at the University of
Southampton (and later developed by AT&T Bell Laboratories) allowed
the signal to be boosted within the fibre itself, so modern installations
do not require repeaters at all. Since they carry only light, optical fibres
are immune to electrical interference, so they can also be used for
short-range communications, for example in aircraft.
1977 The British Post
Office begins sending
live telephone traffic
through optical fibres.
1977 US telephone
companies begin
sending telephone calls
through optical fibres.
1978 AT&T and the
Post Office announce
10 year plan to
develop transatlantic
optical-fibre cable.
1984 British Telecom
(formerly the Post
Office) lays the first
submarine fibre to the
Isle of Wight.
June 2013 Physics: transforming lives
I 25
Optical fibres
Medicine
One of the first uses of optical fibres was in the endoscope, which
allows doctors to see inside patients’ bodies without expensive and
invasive surgery. This paved the way for “keyhole” surgery, in which
optical fibres not only relay images but can also be used to send a
laser beam to carry out surgery, so only a tiny opening is needed.
Fibre lasers
Fibre lasers, also developed at Southampton, can have active regions
of several metres wound into efficient, compact designs that can
generate very high-power beams. They are used in laser cutting and
welding, and they are a candidate for the next generation of research
lasers emitting extremely intense X-ray light.
Sensors
Optical fibres make excellent and inexpensive sensors for
environmental, chemical and biological monitoring in such places
as mines, oil wells and other remote locations. When the fibre is
stretched or heated, this alters the characteristics of light
transmission along it. The fibre-optic research group at the University
of Southampton is working with a local company, SENSA, to develop
a temperature sensor that can work across a distance of 100 km.
They are also developing a strain sensor for monitoring large
structures like bridges, dams and roads.
1986 The first opticalfibre cable across
the English Channel
begins service.
26 I IOP Institute of Physics
1988 The first
transatlantic
optical-fibre cable
begins service.
1987 Physicists
at the University
of Southampton
announce “optical”
amplifiers that are
built into optical
fibres, removing the
need for repeaters.
1991 Japanese
researchers
successfully send
a signal through 1
million km of fibre.
Optical fibres cover the globe, connecting continents
through submarine cables. These are the backbone of
the internet and all telecommunications networks.
Future
Work continues to increase the capacity of optical-fibre cables and
reduce the cost of installing them. In the last decade the use of “optical
amplifiers” – sections of fibre “doped” with elements to boost the
signal – have done away with the need for expensive repeaters. Other
developments include the use of “optical solitons” that have enabled
the development of ultra-fast communications across vast distances.
One of the most exciting developments are photonic crystal fibres,
developed by Philip Russell and colleagues at Southampton and
Bath universities. These have air channels surrounding the central
core, which allows light to be manipulated in many novel ways that
could lead to the development of high-power lasers and gas sensing.
The most significant application is the laser generation of white light
(“supercontinuum” generation), which can be tuned to particular
wavelengths for advanced microscopy in the biosciences.
UK researchers are also making optical fibres out of materials other
than glass. For example, plastic optical fibres could be used for
transmitting information around the house or be incorporated into
textiles and clothing as sensors.
1996 Philip Russell
at the University
of Southampton
demonstrates the
photonic crystal fibre.
1997 The 28,000 km
“fibre-optic link around
the globe” connects the
UK and Japan through
one continuous cable.
2003 Optical fibres
connect all of the
continents except
for Antarctica.
2009 Sir Charles Kao
is awarded the Nobel
Prize in Physics for
his work developing
optical fibres.
June 2013 Physics: transforming lives
I 27
Optical fibres
Facts and figures
£31
bn expected value
of world market for fibre-optic
components by 2015
28,000 km
the
length of one continuous opticalfibre cable around the globe,
linking the UK and Japan
1.1 m
kilometres of
undersea optical-fibre cable had
been installed worldwide in 2010
1.35
bn kilometres of
optical fibre currently in service
across the world
60,000
gb capacity
of the planned submarine cable
to connect Ireland to New York
in 2013
60,000
laparoscopic
gall bladder operations in the UK
each year
40%
of bowel cancer
operations are now performed via
keyhole surgery
28 I IOP Institute of Physics
UK researchers are
now making optical
fibres out of materials
other than glass.
For example, plastic
optical fibres could be
used for transmitting
information around
the house or be
incorporated into
textiles and clothing
as sensors.
Cancer treatment
Research into the nature of matter and the structure
of the universe has led to life-saving techniques to
diagnose and treat cancer.
The science
Cancer refers to a wide group of
diseases in which cells divide
uncontrollably, producing a tumour
that seriously disrupts surrounding
tissues. When cancers are
particularly aggressive, these outof-control cells can also spread to
other parts of the body, causing yet
more damage.
Radiotherapy involves directing
high-energy radiation – such as X-rays and beams of particles,
including electrons and protons – at a tumour to destroy it. The aim is
to damage the DNA of the cancer cells to stop them proliferating, while
ensuring that the radiation dose received by healthy tissue is small
enough that it can recover. The particle accelerators that produce these
high-energy beams were originally developed for the study of particle
and nuclear physics.
The chances of surviving cancer are greatly enhanced by early and
accurate diagnosis, and knowing its precise location and size. Here,
too, physics has provided many of the most important tools. Exploring
the structure of the universe on the very small scale (atomic, nuclear
and particle physics) or the large scale (astronomy and cosmology)
requires the development of new ways of “looking” at things that
cannot be seen with the naked eye. This ability to visualise what
cannot ordinarily be seen has led to the advanced imaging that
underpins modern medical diagnostics.
How does radiotherapy work?
When a charged particle or an X-ray passes through any substance,
it knocks out electrons, leaving a trail of ionisation. When it passes
through the body, this ionisation can cause a break in one or both
of the spirals that make up the DNA inside cells. If the damage is
small, the cell’s natural repair mechanisms can fix it. But a complex
double-strand break – in which there are multiple breaks close
together in each helix – is too difficult to repair, leaving the cell unable
to reproduce successfully. By carefully designing the treatment plan
to accumulate a high radiation dose in the tumour, while keeping the
dose to normal tissue low enough for repair mechanisms to work, the
tumour can be destroyed.
June 2013 Physics: transforming lives
I 29
Cancer treatment
What physics does this rely on?
−− Medical physics
−− Electromagnetism
−− Particle physics
−− Nuclear physics
−− Astrophysics
−− Atomic and molecular physics
−− Acoustics
−− Materials science
−− Computational physics
Impact
One in three people will get cancer at some point in their lives. The
chance of getting cancer increases with age, with about two-thirds
of cancers occurring in people over the age of 65. In 2010, there
were around 157,250 deaths from cancer in the UK. Although cancer
survival rates have doubled in the past 40 years, the number of
sufferers increases each year because of advances in diagnosis and an
ageing population.
More than half of cancer patients will receive radiotherapy as part
of their treatment, and radiotherapy contributes about 40% to the
successful treatment of cancer. Half of the world’s 20,000 particle
accelerators are in use in hospitals, and each can treat between 4500
and 6500 patients per year.
Increasingly, patients are being treated with more advanced
radiotherapy treatments, such as proton-beam and gamma-ray
therapies. In 2012 approximately 70,000 patients worldwide received
proton beam therapy, but it is estimated that 137,000 patients per year
could benefit from the treatment in the US alone. Worldwide there are
around 150 Gamma Knife units, which have collectively treated around
500,000 patients with brain tumours.
1895 German physicist 1896 French physicist
Wilhelm Röentgen
Henri Becquerel
discovers X-rays.
discovers radioactivity
from uranium and
Marie Curie theorises
that its source is
the atom itself, for
which they receive
the Nobel Prize in
Physics in 1903.
30 I IOP Institute of Physics
1903 Discovery of
the Bragg Peak by Sir
William Bragg – the
basis of proton and
ion-beam therapy.
1911 Discovery of
superconductivity
by Heike Onnes.
Superconductivity
enables the strong
magnetic fields
used in MRI.
Early detection of cancer through physics-based
imaging techniques greatly increases the chances of
successful treatment. Better diagnosis and shorter
waiting times also means an enhanced quality of life.
The Department of Health announced a £250 m investment to build
two proton-beam therapy centres in the UK by 2017. It is estimated
that more than 1500 patients per year would benefit from the
establishment of a new National Proton Beam Therapy Service in the
UK. Today there are 43 proton and carbon-ion centres worldwide, and
23 more are planned or under construction. The UK is a key supplier of
component parts for these modern accelerators.
Early detection of cancer, for example through physics-based imaging
techniques, greatly increases the chances of successful treatment.
Better diagnosis and shorter waiting times also mean that people
living with the disease can have an enhanced quality of life. In
addition to the human costs of the disease, cancer also exacts huge
economic costs. The direct healthcare expenditure in the UK is
£5.6 bn a year. There are also additional costs through time off work,
the impact on family and friends of continuing care, and the loss of
productivity due to premature death.
Applications
Cancer diagnostics
There are several sophisticated diagnostic techniques that are based
on physics, and the number is growing.
Computed tomography
Computed tomography (CT) scanners use X-rays to produce 3D
images of the internal anatomy, using sophisticated software to
reconstruct the image. They were first developed by physicists in
the 1960s, and the first scanner was built at EMI Laboratories in
Hillingdon, earning its creator Sir Godfrey Hounsfield a share of the
1979 Nobel Prize in Medicine.
1913 Lord Ernest
Rutherford – while
based at the University
of Manchester – and
Niels Bohr develop a
theory of the structure
of the atom.
1914 Research begins
at the Sorbonne’s new
Radium Institute into
medical treatment of
cancer using radium.
1928 British physicist
Paul Dirac postulates
the existence of the
positron, for which he
was awarded the Nobel
Prize in Physics in
1933. These particles
are now routinely
used for cancer
detection in PET.
1929 Cyclotron
developed by Ernest
Lawrence at Berkley,
for which he won
the Nobel Prize in
Physics in 1939.
June 2013 Physics: transforming lives
I 31
Cancer treatment
Single photon emission computed tomography
A single photon emission computed tomography (SPECT) scan is a
non-invasive nuclear imaging test that shows the blood flow to tissues
and organs and is widely applied in oncology. It uses radioactive tracers
that are injected into the blood to produce pictures of blood flow to
major organs, primarily in the brain and heart. The tracers generate
gamma-rays, which are detected by a gamma camera. A computer then
prepares 3D images of the scanned organ. A key feature of this test is
that the tracer remains in the blood stream rather than being absorbed
by the surrounding tissues, thus limiting the images to areas where the
blood flows.
Positron emission tomography
Positron emission tomography (PET) uses positrons to produce
functional images of the body. Positrons are the antimatter version of
the electron and their existence was first predicted by British physicist
Paul Dirac in 1928. In PET scanning, a positron-emitting radionuclide
isotope is attached to a sugar molecule that is absorbed by cells in
the body where there is a lot of metabolic activity, such as in growing
tumours. Once inside the tumour, the radionuclide emits a positron,
which soon meets an electron and the two particles annihilate, emitting
a pair of high-energy gamma-ray photons. These pass through the body
and are picked up by sensitive detectors. With the use of sophisticated
software to analyse where the gamma rays originated, it is possible to
create a highly detailed 3D image of the tumour. PET scans are often
combined with CT scans to give even more precise information about
the shape, size and location of the tumour, as well as the position of
nearby critical organs.
The accelerators that are used to create the positron-emitting
radionuclides, and the gamma-ray detectors that create the PET
1932 Discovery of
the positron by Carl
Anderson, for which he
won the Nobel Prize in
Physics in 1936.
32 I IOP Institute of Physics
1944 Isador Rabi
receives the Nobel
Prize in Physics for his
discovery of nuclear
magnetic resonance
(NMR). This alignment
of atomic nuclei in a
strong magnetic field is
the basis for MRI.
1946 US physicist
Robert Wilson proposes
the use of protons for
cancer radiotherapy.
1952 Felix Bloch
and Edward Purcell
awarded the Nobel
Prize in Physics for
showing that nuclear
magnetic precision
measurements may
be made in liquids,
leading to the idea of
using NMR in living
tissue (as in MRI).
Cancer treatment
images, were first produced by particle physicists trying to understand
the nature of matter.
Magnetic resonance imaging
Magnetic resonance imaging (MRI) uses very high magnetic fields and
rapidly varying electromagnetic fields to detect the distribution of protons
in the body and so create 3D images of the organs. By manipulating
the electric and magnetic fields, information about how the body is
working can also be obtained. This technology was originally developed
to study structure of the atomic nucleus, and makes use of large
superconducting magnets. Unlike X-rays, which cannot distinguish the
detailed structure of soft tissues, MRI can produce high-resolution
images that reveal damaged and abnormal tissue.
The related technique of magnetic resonance spectroscopy can be
used to map the chemical composition of tumours, and so characterise
them without the need for an invasive biopsy. It is capable of predicting
the response to chemotherapeutic drugs at an early stage in the
treatment cycle, so that if a drug is not effective an alternative can
be tried as soon as possible. In the developing field of interventional
MRI, tumour surgery can be performed while the patient is inside the
scanner, so surgeons can ensure that the whole tumour is removed and
avoid the need for repeated operations.
Ultrasound
In ultrasound scans, high-frequency sound waves are used to create an
image of part of the inside of the body. Pulses of ultrasound are sent
from a probe through the skin and then bounce back from structures
inside the body to be detected by the probe and displayed.
Optical coherence tomography
Optical coherence tomography (OCT) is a form of “optical ultrasound”.
1951 First cobalt-60
teletherapy unit
produced in Canada.
1954 First treatment
of cancer patients with
subatomic particle
beams at Berkeley
Radiation Laboratory
in California.
1969 Sir Godfrey
Hounsfield creates
the CT scanner at
EMI Laboratories in
Hillingdon, for which he
shares the 1979 Nobel
Prize in Medicine.
1971 First medical
CT scan is made, of
a cerebral cyst in a
patient in London.
June 2013 Physics: transforming lives
I 33
Cancer treatment
Infra-red laser light is shone on the skin and the light that is reflected
back from the tissue layers just beneath the surface can be collected
to form a very high resolution image. These images are much more
detailed than those produced by MRI, but OCT can only penetrate a
few millimetres. This makes them most useful in detecting cancer of the
skin and oesophagus, for example.
Selected ion flow tube mass spectrometry
Selected ion flow tube mass spectrometry is a technique that was
originally developed by astrophysicists at the University of Birmingham
who were investigating the chemistry of interstellar clouds. The
technique is able to sense tiny amounts of gas, and can be used to
detect certain cancers by analysing a sample of a patient’s breath.
Cancer treatment
Radiation kills cells, particularly cancer cells, by disrupting DNA and
preventing the cells from reproducing. Radiation can be delivered in
several ways:
External beam radiotherapy
Particle accelerators originally developed by physicists to study
subatomic particles have been used to generate beams of radiation
to treat cancer since the 1950s. Electron linear accelerators (linacs)
are the most common in use and create beams of X-rays or electrons.
The first electron linac was used for radiotherapy in the Hammersmith
Hospital in 1953; today, every major cancer hospital has several
electron linacs for radiotherapy. Other linacs are able to produce
a variety of radioactive agents that are used in the diagnosis and
treatment of cancer.
Protons were first suggested as an alternative to X-rays by Robert
Wilson in 1946, and the first patient was treated with protons in
Berkeley, California in 1954. The first hospital-based proton therapy
1974 The first
commercial PET
machine is built.
34 I IOP Institute of Physics
1980 The first clinically
useful MRI image is
produced.
1989 First hospitalbased proton therapy
is carried out in
Clatterbridge, Wirral.
1992 Development of
multileaf collimators at
the Christie Hospital in
Manchester, which help
target the radiation
beam more precisely.
Cheaper and more compact accelerators and beamdelivery systems will make proton and light-ion therapy
accessible to many more patients.
centre was established in Clatterbridge in the Wirral in 1989, where
they treat eye cancer. Modern proton beam therapy is the most
precise form of radiation treatment available today. It destroys a
primary tumour site but leaves surrounding healthy tissue and organs
almost completely intact, making it particularly suited to treating
childhood cancers.
Brachytherapy
Brachytherapy uses artificially produced radioactive “seeds” enclosed
inside protective capsules, which are delivered to the tumour, where they
emit beta or gamma rays, to give a highly localised dose. The capsules
can be removed after treatment, or in some cases left in place.
Boron neutron capture therapy
Boron neutron capture therapy is used to treat cancers of the head and
neck. A non-radioactive form of boron is injected into the tumour and
then a beam of neutrons is fired at it. Boron is used because it absorbs
neutrons much more readily than human tissue, and when it does it
forms lithium ions and high-energy alpha particles, which together
deliver the radiation dose to the tumour.
Computer-aided treatment
Increasingly, computer-based methods are being used together with CT
and MRI scans to “sculpt” the beam so that its shape matches that of
the target tumour. Alongside image-guided robotic surgery and the use
of laser scalpels, this is leading to ever more precise cancer treatment.
Future
Work continues to refine imaging techniques so that radiation can
be targeted to match the tumour shape ever more precisely. Cheaper
and more compact accelerators and beam-delivery systems will make
proton and light-ion therapy accessible to many more patients. New
ideas, such as using nano-particles to increase the radiosensitivity of
1995 First patient
is treated with
Intensity Modulated
Radiotherapy,
which uses MRI
and CT together
with computerised
calculations of the best
dose-intensity pattern
for tumour shape.
2003 Sir Peter
Mansfield of
the University of
Nottingham wins
the Nobel Prize
in Physiology or
Medicine, along with
Paul Lauterbur of the
University of Illinois,
for their “discoveries
concerning magnetic
resonance imaging”.
2004 Scientists begin
working on totally
non-invasive cancer
tests, such as the
breath test, SIFT.
2007 A compact device
that can generate THz
radiation portably
is created at the US
Department of Energy,
making THz imaging in
hospitals viable.
June 2013 Physics: transforming lives
I 35
Cancer treatment
cancer cells while leaving healthy cells unaffected, will allow cancer to
be treated with lower radiation doses and thus fewer side effects.
A new proof-of-principle accelerator known as EMMA (Electron Machine
with Many Applications) is being constructed at the Science and
Technology Facilities Council’s Daresbury Laboratory in the UK. While
research is at its very early stages, the experience gained in building this
machine may prove useful for future proton and carbon-ion accelerators
that are used in treating cancer. EMMA is driven by an energy-recovery
linear accelerator called ALICE. The latter also drives an infrared freeelectron laser, which is being used together with a scanning near-field
microscope as a potential diagnostic tool for oesophageal cancer.
The synchrotron light emitted from high-energy electron storage rings
– originally developed for use in particle physics – is of much higher
quality than that available from conventional hospital X-ray machines,
and can be used to produce so-called phase contrast X-ray images.
This technology could potentially be developed into a tool to provide an
earlier diagnosis of breast cancer, for example.
Low-energy terahertz radiation may also have an important role to
play in cancer detection. Terahertz radiation can penetrate several
millimetres of tissue and could be used to detect skin cancer at a
very early stage, as well as cancer of the cervix, breast and colon. It
is safer and less invasive than X-rays. The first terahertz cameras were
developed by astrophysicists to image the distant universe. Londonbased company Teraview has developed a portable probe, which is
currently being trialled. The sensitivity of terahertz imaging can also be
improved with the use of gold nanoparticles and infrared lasers.
2012 New laser
technique shows
potential for future
use in breast cancer
diagnosis, to detect
if abnormalities are
malignant or benign.
36 I IOP Institute of Physics
2012 New
accelerator-driven
infrared free-electron
laser and scanning
near-field microscope
shows potential for
the diagnosis of
oesophageal cancer.
Cancer treatment
June 2013 Physics: transforming lives
I 37
Cancer treatment
Facts and figures
200
different kinds of
cancer affect all parts of the
body, and all can be fatal if
left untreated
324,579 people
diagnosed with cancer in the
UK in 2010
157,250
deaths from
cancer in the UK in 2010
70,000
received proton-beam therapy
± patients
in 2012 worldwide
¹⁄develop
people in the UK will
³ of some
form of cancer
during their lifetime
+ of cancer patients will
½
receive radiotherapy as part of
their treatment
500,000
have
undergone Gamma Knife
treatment for brain tumours
43
proton and carbon-ion
centres available worldwide;
24 more are planned or under
construction
10,000
hospital
£5.6
bn
the annual
particle accelerators worldwide,
direct cost of all cancers to the
UK economy
38 I IOP Institute of Physics
treat 4500–6500 patients
per year
Physics and DNA
The discovery of DNA structure heralded the birth of
molecular biology – physicists, chemists and biologists
work together to unravel the basic processes of life.
The science
Deoxyribonucleic acid – DNA – is a
large molecule that is found in the
cells of all living things, from bacteria
to humans. It consists of a very
long strand of millions of nucleotide
“base pairs” joined together in a
characteristic double helix.
The discovery of the structure of
DNA in 1953 by biologist James
Watson and physicist Francis Crick
was groundbreaking because it provided an explanation of the basis
of heredity, what genes are and how they work. The double helix can
be unravelled into its two halves and then copied when cells multiply.
During reproduction, DNA strands from each parent are able to join
together to form a completely new and unique set of strands. Genes
work because the bases form a code in which combinations of three
bases translate into any one of 20 amino acids. Depending on the
precise sequence of the code, amino acids are joined together in
different ways to form proteins that make cells and organisms function.
How was the structure of DNA discovered?
The technique used by Watson and Crick to work out the structure
of DNA was X-ray crystallography, which had been developed by
physicists Sir Lawrence Bragg and his father Sir William Bragg earlier
in the century. The Braggs found that when crystal structures are
illuminated with X-rays, atoms within the crystal scatter the X-ray light
to produce characteristic patterns. Using the angle of scattering and
its intensity it is possible to work out the 3D structure of the molecules
that make up the crystal.
The discovery also depended on the work of Maurice Wilkins and
Rosalind Franklin at the then newly formed Medical Research Council
Biophysics Unit at King’s College London. They used fibres of DNA to
produce the X-ray diffraction patterns that Watson and Crick studied.
In 1953 they finally made their breakthrough discovery – that DNA
is a double helix with a phosphate backbone on the outside and the
nucleotide bases on the inside.
June 2013 Physics: transforming lives
I 39
Physics and DNA
Following the discovery of the structure, it was physicist George
Gamow who first predicted that a three-letter code was needed to
produce the 20 amino acids, which lead to Crick and Watson to
enumerate the 20 amino acids common to most proteins.
It was Crick’s knowledge as a physicist that enabled him to solve the
mystery of DNA’s structure. This was done using X-ray crystallography,
which continues to be extremely useful in determining the structure
of proteins. Today, new techniques from physics are being used to
understand yet more about the structure and function of biological
molecules, and this understanding is used to create drugs and other
treatments for diseases.
What physics does it rely on?
−− X-ray diffraction
−− Nuclear physics
Impact
The discovery of the structure of DNA led to the development of
the field of molecular biology, in which physicists, chemists and
biologists work together to understand the basic processes of life. This
understanding has led to many advances in the treatment of disease.
DNA sequencing also enabled the development of “DNA fingerprinting”,
which has had a huge impact in solving crime. The UK National DNA
Database now contains over six million samples and is growing by
30,000 per month. As of December 2012, there have been 428,097
crimes matched against the database.
According to the UK Medical Research Council, the industry based on
genomics – including gene-based services, diagnosis and potential
drugs – is worth £3.5 bn a year. In the US, it has been estimated that
spending $2 bn on research in this area over the next decade could
generate a return of between four and 30 times that investment.
1915 UK physicists Sir
William Bragg and Sir
Lawrence Bragg receive
Nobel Prize in Physics
for X-ray crystallography.
40 I IOP Institute of Physics
1953 UK physicist
Francis Crick and US
biologist James Watson
discover the structure of
DNA, with contributions
from UK physicists
Maurice Wilkins and
Rosalind Franklin.
1962 Nobel Prize in
Medicine awarded
to Crick, Watson
and Wilkins
1975 The first complete
genome is sequenced –
of a bacteriophage.
According to the UK Medical Research Council, the
industry based on genomics – including gene-based
services, diagnosis and potential drugs – is worth
£3.5 bn a year.
Applications
DNA sequencing
In the 1970s, US theoretical particle physicists Walter Gilbert and Allan
Maxam developed a method for reading or “sequencing” the bases of DNA,
which involved the use of radioactive markers to label sections of DNA. In
1977 Frederick Sanger simultaneously developed a similar method,
which led to the Nobel Prize in Chemistry in 1980. The Sanger method
has since been adapted and automated, and it was this technique that
was used to sequence the entire human genome, along those of more
than 180 other organisms. Knowledge of the DNA sequences of genes
is crucial to the development of modern drugs and vaccines.
DNA sequencing also led to the development of DNA fingerprinting,
which was developed in 1985 by Sir Alec Jeffreys at the University of
Leicester. By analysing the patterns of certain sections of DNA that
vary from individual to individual it is possible to create a “fingerprint”
that is unique to each person. This technique has revolutionised crime
detection across the world.
Proteomics
Just as X-ray crystallography revealed the structure of DNA, the same
technique is also invaluable in studying the structure of the proteins
that genes encode. New and powerful machines are now available to
do this work. For example, the Diamond Light Source in Oxfordshire,
which opened in 2007, is a powerful synchrotron that accelerates
electrons to nearly the speed of light, and in so doing produces
incredibly bright beams of light, including X-rays. These can be used
to provide exceptionally detailed information about the structure of
proteins. The Diamond Light Source has recently enabled scientists
to produce a synthetic vaccine against foot-and-mouth disease. This
technique could be used to produce safer and more transportable
vaccines for many other diseases in the future.
1980 Frederick Sanger
and Walter Gilbert
receive the Nobel
Prize in Chemistry for
DNA sequencing.
1985 Sir Alec Jeffreys
at the University of
Leicester invents DNA
fingerprinting.
1987 Applied
1990 Gene therapy
Biosystems markets the first carried out.
first automated DNA
sequencing machine.
June 2013 Physics: transforming lives
I 41
Physics and DNA
42 I IOP Institute of Physics
By using synthetic DNA, researchers have
demonstrated a way of delivering a targeted dose of
drugs or genes directly to the inside of cells with the
potential to target cancer cells.
Alongside these X-ray studies, physicists also use a technique known
as neutron scattering, which uses beams of subatomic particles.
Additionally, nuclear magnetic resonance – another technique based
on physics research – is also used to study the structure of proteins
and other biological elements, and often all of these techniques are
combined along with genetic manipulation methods to understand
biological processes.
Future
New, extremely powerful X-ray devices known as “free-electron lasers”
are being developed that would not only show the structure of proteins
but could also enable snapshots of molecular biological processes to
be recorded as they take place. This would allow even more detailed
understanding of how the body works, providing yet more strategies for
treating disease.
New methods of DNA sequencing are being developed all the time, and
it is now possible to produce DNA microarrays, which can sequence
an entire genome in a single device no bigger than a postage stamp.
Some of these methods involve physics — such as the use of “quantum
dot” nanocrystals as fluorescent markers, instead of conventional dyes.
The inspiration also works in the other direction, from biology to
physics, as physicists begin to design nanoscale devices made of DNA
that are able to self assemble. These might be used for molecular
sensing or intelligent drug delivery, for example. By using synthetic
DNA to make nanoparticles known as DNAsomes, researchers have
demonstrated a way of delivering a targeted dose of drugs or genes
directly to the inside of cells; this method of drug delivery has the
potential to target particular kinds of cells, such as cancer cells.
1994 American
computer scientist
Leonard Adleman
proposes the DNA
computer.
1994 Affymetrix
produces the first
DNA microarray,
using semiconductor
manufacturing
techniques.
1997 Dolly the
sheep is the first
cloned mammal.
2000 Human genome
project is completed.
June 2013 Physics: transforming lives
I 43
Physics and DNA
Facts and figures
428,097
crimes
matched against the UK National
DNA Database
1
day the amount of
time taken to sequence a human
genome
+ organisms have had
180
their genomes sequenced to date
£3.5
bn the value of
the global market in genomics,
gene-based services, diagnostics
and potential drugs
The inspiration also
works in the other
direction, from
biology to physics,
as physicists begin
to design nanoscale
devices made of DNA
that are able to self
assemble. These might
be used for molecular
sensing or intelligent
drug delivery, for
example.
10
trillion
the number of simultaneous
calculations that cubic
centimetre-sized DNA computer
could theoretically perform
2007 The UK
Diamond Light Source
starts operation.
44 I IOP Institute of Physics
2012 Early research
into using DNA
for high-capacity
information storage.
2013 Synthetic vaccine
for foot-and-mouth
disease produced using
data obtained from the
Diamond Light Source.
Energy efficiency
Physics is providing a multitude of ways toreduce
energy use, significantly reducing both costs and
carbon-dioxide emissions.
The science
Whenever we use energy – to light
or heat our homes, or to operate
electrical appliances – some of
that energy is wasted. No process
is 100% efficient but by making
use of principles from physics,
it is possible to increase energy
efficiency considerably, and so
reduce the amount of energy
that is lost. For example, at least
95% of the electricity consumed
by an incandescent light bulb is turned into heat. Light-emitting diode
(LED) light bulbs, developed from modern condensed-matter physics,
are 10 times more efficient and last much longer. When electricity
passes through wires, energy is lost as it encounters resistance. But
some special materials, under the right conditions, are able to transmit
electricity with no resistance at all. These “superconductors” have the
potential to save considerable amounts of energy that is otherwise lost
as unwanted heat.
How do LEDs work?
LEDs are made from electroluminescent crystals, which emit light when
an electric current is passed through them.
An LED is made of two layers – one that has extra electrons and one
that has spare “holes” where electrons can sit. When a current passes
through the LED, the extra electrons travel to the holes, releasing a
photon – a particle of light of a specific colour, depending on the
precise make-up of the material.
The first LEDs produced red light, but by adjusting the chemical
composition of the electroluminescent crystals it is now possible to
produce LEDs of many different colours. White light for LED light bulbs
may be obtained from a combination of red, green and blue LEDs.
Another more commonly used technique involves coating a blue LED
with phosphors, which convert the light into a broad spectrum of white
light suitable for both commercial and domestic lighting.
June 2013 Physics: transforming lives
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Energy efficiency
What physics does it rely on?
−− Opto-electronics
−− Semiconductors
−− Condensed-matter physics
−− Low temperature physics
−− Materials science
−− Thin films
−− Plasma physics
Impact
Energy efficiency plays a huge role in both reducing carbon-dioxide
emissions and saving money for householders and businesses. Today,
20% of the world’s electricity is used for lighting, and this could be
reduced to four per cent with optimal use of LED lighting. In the UK this
would result in 40 million tonnes less carbon dioxide being emitted
each year – a reduction of around eight per cent of total emissions.
In the US, the switchover would result in financial savings of $30 bn
a year. Worldwide, the switchover to LEDs would enable the closure of
560 major power plants and result in annual carbon-dioxide savings
equal to that emitted by all of the cars on the planet.
Other technologies have similarly impressive impacts. In Europe,
carbon-dioxide emissions could be reduced by 85 million tonnes per
year – 25% of the EU’s current reduction target – through the optimal
use of energy efficient glass, which is coated with a thin film to reduce
heat loss. It has also been calculated that the EU could reduce carbondioxide emissions by a further 53 million tonnes if high-temperature
superconductors were developed for use in power plants.
At the same time, sales of energy-efficient products are generating
significant income in this rapidly growing market. From 2010 to 2015,
the global energy-efficient lighting market is projected to increase from
$13.5 bn to $32.2 bn per year. General Electric estimates the potential
1907 H J Rounds
of Marconi Labs
discovers the
phenomenon
of electroluminescence.
1911 Dutch
physicist Heike
Kamerlingh Onnes
discovers the
phenomenon of
superconductivity.
46 I IOP Institute of Physics
1927 Russian
scientist Oleg
Vladimirovich
Losev reports the
creation of the
first LED.
1962 Nick
Holonyak at the
General Electric
Company reports
the first practical
visible spectrum
(red) LED.
1968 Monsanto
mass produce
red LEDs using
gallium arsenide
phosphide.
Today, 20% of the world’s electricity is used for lighting,
and this could be reduced to four per cent with optimal
use of LED lighting.
worldwide market for superconducting generators in the next decade is
worth $20–30 bn. Another burgeoning market, phase-change materials,
is expected to grow to $1.5 bn by 2015.
Applications
LED lighting
LED light bulbs are now available to replace any standard household
bulb. They use around six times less electricity than an incandescent
light bulb, and 70% of the electricity of a compact fluorescent light
(CFL) bulb. They can last for around 50,000 hours and have many
advantages over CFLs – they use less energy, contain no mercury,
have no vacuum, are more compact and can be controlled to produce
light of any colour. They are particularly well suited to commercial and
hospitality settings, where lights may be on almost continuously – here
the payback time can be as short as one to three years.
They are also now widely used in car headlights, aircraft lighting and
traffic lights. If the UK were to replace all of its 25,000 traffic lights with
LED bulbs it could save 50,000 tonnes of carbon dioxide and £16.7 m
each year. LEDs are also proving useful for lighting supermarket freezer
display cabinets, where they add less heat and perform better than
fluorescent lighting, as well as being more attractive to customers.
Power plants and transmission lines
When electricity is generated in power stations with steam or gas
turbines, at least 50%, and often as much as 70%, of the energy is
lost as heat; and then yet more is lost (3% to 10%) along the electrical
transmission and distribution lines to users. But, unlike copper wire,
some materials are superconducting – which means that they transmit
electricity with no resistance and no loss of heat. Superconductivity
had been thought to occur only at the very lowest of temperatures (less
than minus 260°C), but in the 1980s Nobel-prize winning research
1972 M. George
Craford invents the
first yellow LED
and improves the
brightness of red
LEDs by 10 times.
1986 Georg
Bednorz and K.
Alex Müller observe
high-temperature
superconductivity in
ceramic materials.
1987 Bednorz and
Müller win the Nobel
Prize in Physics for
the discovery of
high-temperature
superconductivity.
1993 Shuji Nakamura
of Nichia Corporation
demonstrates the first
high-brightness blue
LED based on gallium
indium nitride.
June 2013 Physics: transforming lives
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Energy efficiency
led to the discovery of so-called “high-temperature superconductors”
(HTSs). These still operate at low temperatures, but now less than
minus 140°C, which could, in the future, make them a feasible
supplement to traditional copper wire. However, high material costs and
the cost of energy required to cool the superconducting transmission
lines means they have to date only been used in some cases to replace
short lengths of underground high-voltage cables to an installation.
To transmit power for electricity over great distances, high-voltage DC
(HVDC) power lines are currently one of the best available options.
These have lower power losses than conventional AC transmission
systems due to their greater capacitance, and take up less space than
AC lines. Over long distances lower operating costs from reduced power
losses makes HVDC an attractive option.
Energy-efficient windows
It was first demonstrated in the 1970s that a thin film of metal oxide
could be deposited onto glass to make windows much more energy
efficient. The technique used is called magnetron sputtering, which
was first developed in plasma physics research. The windows have
been widely used in the last two decades, and their uptake is growing
rapidly, especially for new-build, where they are required by building
regulations. In the UK, low emissivity, high solar gain windows are
able to reduce heat loss by as much as 40% compared to standard
double glazing. They work by transmitting sunshine and visible light, but
blocking infra-red frequencies (heat), so reducing the amount of heat
leaving a room. Coatings are also available that are more suited to hot
climates to help keep homes cool in the summer.
Heating and cooling materials
The heating and cooling of buildings accounts for one third of all
carbon-dioxide emissions globally. Phase-change materials (PCMs) are
a recent innovation that is helping to significantly reduce the amount
1996 Nichia
Corporation produces
the first commercially
available white LEDs.
48 I IOP Institute of Physics
2001 Philips Lumileds
produces the first
commercially available
high-power white LED
light bulbs for lighting.
2006 Superconducting
transmission lines
begin supplying power
to 70,000 households
in New York.
2010 UK-based
Converteam install the
first superconducting
generator in a
hydropower plant
in Bavaria.
The heating and cooling of buildings accounts for
one third of all carbon-dioxide emissions globally.
Phase-change materials (PCMs) are a recent
innovation that is helping to significantly reduce the
amount of energy needed.
of energy needed. For example, a bioPCM gel being used in a new
building in the University of Seattle has reduced the amount of energy
needed to cool the building by 98%. UK-based Star Refrigeration is
using carbon dioxide as a PCM, because it changes from a liquid to
gas at a very low temperature, making it ideal for cooling computers
in server farms. By piping carbon dioxide through heat exchangers, the
company recently demonstrated that it could pull nearly twice as much
heat from the computers as the systems used at present. In 2009 the
market for PCMs was already worth $300 m. It is growing at a rapid
pace and is set to reach $1.5 bn per year by 2015.
Future
Domestic appliances
Advanced PCMs have the potential to help make appliances even more
energy efficient. For example, it has been shown that PCMs can store
the waste heat produced by a dishwasher in one cycle for use in a
later one. Such a process has been shown to make dishwashers 22%
more efficient. PCMs could be used to improve the energy efficiency of
a wide range of domestic appliances, including dishwashers, washing
machines, fridges, freezers and ovens.
Smart dust
Smart dust is a system of tiny microelectromechanical systems (MEMS)
like sensors, each smaller than a snowflake, which can measure their
environment and report back on changes. This could include monitoring
even the smallest changes to big structures like bridges, or to monitor
and automatically adjust lighting and temperature in buildings. Instead
of a single thermostat for a whole room, thousands of these tiny
devices – each less than a millimetre in size – could gather information
from all over the building about where people are, how warm it is, how
light it is, and then use this information to control lighting and heating
in a smart way.
2012 Researchers
at the University of
Leipzig claim to have
discovered a graphitebased material that
is superconducting
at room temperature
and higher.
2012 Cambridge
physicists develop a
technique for growing
LEDs on silicon,
reducing the cost of
manufacture five-fold.
June 2013 Physics: transforming lives
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Energy efficiency
Facts and figures
$30 bn
36
mths the time
taken historically for the efficiency
potential
worldwide market for
superconducting generators in the
next decade
50,000 hrs
predicted
market for phase change
materials in buildings by 2020
and light output of LEDs to
double
the
lifetime of an LED light bulb
$265
bn predicted
savings if US moves rapidly to
LED lighting by 2027
85
m tonnes of carbon
dioxide could be saved each year
– 25% of the EU target – through
the optimal use of low-emissivity
glass by 2020
53
m tonnes potential
reduction in carbon-dioxide
emissions in the EU if hightemperature superconductors
were used in power plants
50 I IOP Institute of Physics
$1.5 bn
40
m tonnes possible
reduction in annual carbon-
dioxide emissions in the UK from
the switchover to LED bulbs
9
Detecting explosives and pollutants
How UK-funded particle physics research is able
to save lives during conflicts and help protect the
environment.
The science
Techniques used by physicists for
detecting subatomic particles have
led to a new chemical-monitoring
system. DUVAS (Differential
UV Absorption Spectroscopy),
developed by Imperial College
London physicists John Hassard
and Mark Richards, and based
on research funded by the UK’s
research councils, chiefly the
Engineering and Physical Sciences Research Council, and the Science
and Technology Facilities Council, can rapidly detect Chemical Warfare
Agents (CWAs) and Improvised Explosive Devices (IEDs), and provide
real-time monitoring of airborne pollutants. It was commercialised via
Imperial College London spin-out Duvas Technologies Ltd.
The physics behind DUVAS
DUVAS is based on UV spectroscopy, a technique that is able to
identify different types of airborne atoms, molecules, and particles
because they each absorb different wavelengths of UV light, and so
produce dark lines in different places on a spectrum.
The DUVAS system also uses special processing methods developed
by particle physicists. Computers enable the subatomic particles
created in particle-physics experiments to be represented by peaks in
a spectrum of different masses, but these particles’ peaks will often
overlap in that mass spectrum. Specialised processing separates
out these overlapping peaks and so allows physicists to analyse
the individual particles that caused them. This processing has to be
incredibly fast as particles are created at a very high rate – around
200 m measurements must be taken every second.
What physics does it rely on?
−− Particle physics
−− Molecular physics
−− Statistical physics
−− Computational physics
−− Atmospheric physics
−− Optics
June 2013 Physics: transforming lives
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Detecting explosives and pollutants
Impact
The DUVAS system can simultaneously detect over 20 different chemicals
at a parts-per-billion level every few seconds, while its closest rival takes
an average reading of just one type of chemical over a five-minute period.
The ability to monitor several airborne chemicals in real time is important,
as research suggests that short exposures to high concentrations of
pollutants are far more damaging to health than longer exposures to low
concentrations. The market for pollution-monitoring devices is significant
– air pollution causes around three million deaths per year worldwide
(30,000 of which are in the UK), while up to 10% of China’s GDP is lost
due to air-pollution-related costs.
In 2009, DUVAS’s technology was adopted by a major European
defence company for CWA and IED detection. Almost 60% of UK armed
forces deaths due to hostile actions since 2001 in Afghanistan have
been caused by IEDs or landmines. Several countries have a range of
CWAs available to them.
Applications
Protecting military personnel
The DUVAS system can quickly and accurately sense ammonium
nitrate explosives, and has passed trials for use in the defence
sector detecting IEDs – which are usually made from ammonium
nitrate. A major European defence company is now developing CWA
detection systems, which will help protect soldiers and civilians from
chemical weapons attacks, and is preparing to produce IED detection
systems, based on the DUVAS technology platform. Meanwhile, Dutch
independent research organisation TNO has validated the technology
against a wide range of CWAs, paving the way for more generalised
defence-sector sensors.
1996 Imperial College
London’s John Hassard
and colleagues receive
funding from NERC,
PPARC and EPSRC to
develop the GUSTO
system for air quality
monitoring based on
methods of detecting
subatomic particles.
52 I IOP Institute of Physics
1999 The first GUSTO
prototype system
is created.
2003 Proof of principle
established and
further development
of fixed roadside unit
is carried out.
2006 Work starts on
development of mobile
unit as part of EPSRC
funded MESSAGE
programme.
The DUVAS system can simultaneously detect over 20
different chemicals at a parts-per-billion level every few
seconds, while its closest rival takes an average reading
of just one type of chemical over a five-minute period.
Detecting industrial pollutants
DUVAS can be tailored to detect toxic industrial chemicals, and is
being used by a major oil and gas company in South America for
environmental monitoring – with the aim of stopping pollution – around
oil pipelines. The system can also monitor for leaks and thus forewarn
that action needs to be taken to stop the leakage before it causes an
explosion. Duvas Technologies Ltd is also negotiating with two major
oil companies for the use of its technology at petrochemical plants in
the Middle East North Africa region, and with potential partners and
distributors in China.
Monitoring air quality
Between 2010 and 2012, DUVAS systems monitored for pollutants
produced through vehicle emissions at three primary schools in Brighton
and Hove before, during, and after “Walk to School” week. The main
purpose was to assess what impact Walk to School Week has on traffic
emission levels and local ambient air quality. Project data are still being
analysed, while several other district councils and municipalities, and the
US Environmental Protection Agency, are also evaluating the technology.
Future
Currently 30 DUVAS air-quality monitors are being used at ports and
airports worldwide, with a deal for hundreds of units being negotiated
with a South American company in the petrochemical sector.
Meanwhile for air-quality monitoring in urban areas, development work
in conjunction with Imperial College London’s computing department
has enabled DUVAS readings to be displayed over Google Earth maps
and potentially be combined with weather and traffic information. The
mapping of air-quality could aid town and congestion planning, as well
as inform people with respiratory problems.
2008 The first mobile
DUVAS system is
created and Imperial
College London spinout Duvas Technologies
Ltd is founded to
commercialise
this technology.
2009 John Hassard,
as founder of Duvas
Technologies Ltd,
wins the ‘Best of
British’ category
of the BBC Focus
Innovation Awards.
2009 The DUVAS
system undergoes
testing for IED
detection by a major
defence company, who
subsequently adopt the
technology for their IED
detection products.
2010 Imperial College
London’s Mark Richards
begins air quality
monitoring projects,
including analysing
vehicle emissions in
school playgrounds
and nearby roads as
part of the UK’s Walk
to School campaign.
June 2013 Physics: transforming lives
I 53
Detecting explosives and pollutants
Facts and figures
± deaths worldwide are
3
m
caused by air pollution each year.
30,000 of which are in the UK
< of China’s GDP is
10%
lost due to air-pollution-related
costs
±of UK armed forces
60%
deaths due to hostile actions
since 2001 in Afghanistan
have been caused by IEDs or
landmines
2010 Sales of
DUVAS systems to
the defence and
security sector begin.
54 I IOP Institute of Physics
2012 Orders
for hundreds of
DUVAS units for the
petrochemical sector
being negotiated.
The DUVAS system
can quickly and
accurately sense
ammonium
nitrate explosives, and
has passed trials for
use in the defence
sector detecting
IEDs – which are
usually made from
ammonium
nitrate.
10
Data storage
The Nobel prize-winning discovery by physicists
made it possible to store vast amounts of data in
tiny devices – creating the media revolution.
The science
In 1988, physicists discovered a totally new
phenomenon – “giant magnetoresistance”
– in which very weak magnetic changes
give rise to major differences in electrical
resistance. This turned out to be the perfect
tool for reading data from hard disks,
converting information stored magnetically
into electric current.
How GMR increases data-storage capacity
Each piece of information on a hard disk is stored as a microscopically
small magnetic area. As hard disks get more compact and store
ever more data, these magnetic areas get smaller and weaker.
The phenomenon of giant magnetoresistance (GMR) enabled the
development of ultra-sensitive read-out heads that are able to detect
these tiny signals.
The phenomenon was discovered thanks to techniques developed in
the 1970s to produce very thin layers of matter. GMR only appears in
layers of matter that are just a few atoms thick – so GMR is considered
to be one of the first applications of nanotechnology. It also makes use
of both the spin and the charge of the electron, making it the first
application in the emerging field of spintronics.
What physics does it depend on?
−− Condensed-matter physics
−− Quantum electronics
−− Semiconductor physics
−− Spintronics
−− Electrostatic physics
Impacts
The global market for hard disk drives is currently around $38 bn.
The hard drives of the 1980s and 1990s were used principally in
computers as the main form of data storage, but, as they shrunk in
size, new uses were found. Nowadays, compact hard drives are found
in digital audio players (like iPods) and digital video recorders (like
Freeview+ and Sky+ boxes), so it can be argued that this technology
has brought about the digital media revolution.
June 2013 Physics: transforming lives
I 55
Data storage
Global online music sales are expected to reach $7.7 bn by 2015 as
services like iTunes and Spotify gain momentum. Spending on CDs
and other physical forms of music is expected to decline to $10 bn in
the same period. In the UK, spending on digital music is expected to
overtake physical music sales by 2015. The UK is at the forefront of
this hard-drive industry, with a major Seagate Technology data storage
plant and research and development centre located in Londonderry,
Northern Ireland.
Applications
How have developments in physics increased data storage capacity in
the past three decades?
The discovery of GMR led to the development of the spin valve readout
head, which enabled computer hard drives to store much more data
in smaller spaces than had previously been possible. Hard drives were
already steadily increasing in storage space, but this new technology
led to a trebling in the annual rate of increase in capacity. Tunnel
magnetoresistance – an extension of GMR – allows even greater
sensitivity, and therefore even more compact hard drives, and has now
replaced GMR in modern hard drives.
The hard drives of the 1980s and 1990s were used principally in
computers as the main form of data storage but as they shrunk in size
new uses were found. Nowadays, compact hard drives are found in digital
audio players (like iPods) and digital video recorders (like Freeview+ and
Sky+ boxes) and games consoles such as a PlayStation.
These innovations in turn have led to other transformative technologies.
Without the existence of cheap hard drives capable of storing vast
amounts of data, free search engines like Google would be impossible,
as would free photo – and video-sharing websites such as YouTube,
1970s First techniques
developed to produce
very thin layers of
material – a few
atoms thick.
56 I IOP Institute of Physics
1988 Albert Fert
and Peter Grünberg
discover the
phenomenon of GMR.
1989 Stuart Parkin
of IBM develops the
spin valve, based on
the GMR effect.
1997 IBM
commercialise
the first spin valve
read-out head for
hard disks, enabling
a 1000-fold increase
in data density. This
quickly becomes the
standard technology
for hard disks.
Nowadays, compact hard drives are found in digital
audio players (like iPods) and digital video recorders
(like Freeview+ and Sky+ boxes), so it can be argued
that this technology has brought about the digital
media revolution.
Flickr and Facebook. Free email with very large or unlimited storage
capacity, such as Hotmail, Yahoo, Gmail, would also be impossible.
The existence of digital audio players has led to a huge shift in the
way that music is bought. Last year in the US, more music was bought
online than on CDs for the first time, and the rest of the world is not
far behind this trend. Services like iTunes and Spotify, in turn, rely
on cheap, compact hard drives with enough capacity to store vast
libraries of music. Movie libraries require even more storage capacity,
and consumers are increasingly renting movies by downloading them
straight to their televisions via video-on-demand services rather than
renting DVDs or Blu-rays.
Future
The search is on for a successor technology that can combine high
storage capacity with a high speed of operation. Currently, data is
stored on hard drives or “flash memory” (a light-weight type of storage
used in most smartphones), while a computer uses a different type
– RAM – as its working memory. This is wiped clean when the power
is switched off. A new “universal memory” would combine the speed
of RAM with the storage capacity and stability of a hard disk and the
lightness of flash memory.
There are several promising contenders. British physicist Stuart Parkin
of IBM, who developed the first spin valve read-out head, has led the
development of two of these – magnetoresistive RAM (MRAM) and
Racetrack memory.
As its name suggests, MRAM also makes use of a magnetoresistance
effect. The first commercial MRAMs were developed by Everspin, a
Motorola spin-out company which has just brought an STT MRAM to
market. This makes use of yet another spintronic effect, Spin Transfer
2004 Stuart Parkin
of IBM and Shinji
Yuasa of AIST, Japan,
independently make
junctions using tunnel
magnetoresistance
(TMR) that have
double the capacity
of GMR junctions.
2005 The first
read-out heads
using TMR instead
of GMR are sold.
2007 Albert Fert
and Peter Grünberg
receive the Nobel Prize
in Physics for their
discovery of GMR.
June 2013 Physics: transforming lives
I 57
Data storage
Torque, to write the magnetic data
using pulses of spin-polarised
electrical current instead of a
magnetic field.
Racetrack memory stores
information on magnetic
nanowires just 15 nm thick. The
first prototype Racetrack chip was
showcased in December 2011.
According to IBM this could lead
to a new type of data-centric
computing that allows massive
amounts of stored information
to be accessed in less than a
billionth of a second.
Other technologies in
development that could form
the basis of a new universal
memory include ferroelectric
RAM (FeRAM), phase-change
memory (PCM), programmable
metallisation cells (PMC) and
resistive RAM (ReRAM).
Each of these technologies is
based on physics research of
recent decades.
Facts and figures
$38
bn value of the
global market for hard drives
in 2012
3x
the annual rate of
increase in hard disk storage
capacity trebled in the years
following the commercialisation
of GMR
10,000x
more data is
now stored on a typical hard drive
than those before GMR
4 mb
the capacity of the
earliest hard drives, which were
the size of a large refrigerator and
weighed nearly a tonne
4 tb
(4 million megabytes)
the capacity of the latest hard
drives, which are 20 cubic
centimetres and weigh less than
50 grams
2015
the date when
spending on digital music sales
is expected to overtake physical
music sales
58 I IOP Institute of Physics
Satellite timing and navigation
Einstein’s discoveries underpin technology used by
satellite-navigation systems, bringing major benefit
to the UK economy.
The science
A satellite timing and navigation
system uses coded signals
transmitted from orbit to radio
receivers on Earth to provide
accurate and precise timing
references that are used to
synchronise a variety of civil and
military applications – such as
financial transactions, control
of utilities and determination of
position and velocity. There are
currently two operational Global Navigation Satellite Systems – the US
Global Positioning System (GPS) and the Russian system GLONASS.
Systems in China (Beidou) and Europe (Galileo) are under construction
and expected to be available in 2015, and will provide improved
accuracy and robustness.
The physics behind satellite-navigation
Accurate and extremely precise time-measurement is crucial to
satellite-navigation, and requires the use of atomic clocks. These are
the most accurate clocks available, and the first one was built at the
UK’s National Physical Laboratory in 1955 by UK physicist Louis Essen.
The difference in gravity between the satellite and the receivers on
Earth means that timing corrections based on Einstein’s general theory
of relativity are needed.
Satellite timing and navigation systems use constellations of around
24 satellites in medium Earth orbits (around 22,000 km above the
Earth). To pinpoint a location, a measurement of the distance between
the user and at least three satellites is required. This is achieved by
comparing the relative time of arrival of the three (or more) signals at
the receiver by using a complex signal and coding structure.
What physics does it rely on?
−− Quantum mechanics and atomic physics
−− Space science
−− Satellite technology
−− Atmospheric and solar science
−− General relativity
June 2013 Physics: transforming lives
I 59
Satellite Timing and Navigation
Impact
The impact of satellite timing and navigation can be quantified on
two levels: that generated by companies directly involved in the
provision and manufacture of the satellite and receiving technology,
and the much wider impact of the many industries that now rely on
its capabilities. The satellite-navigation industry itself made a valueadded impact contribution to UK GDP of around £113 m in 2010 and
is expected to generate a value-added contribution to the UK worth
£1.45 bn between 2011 and 2020. More broadly, the technology is a
critical component of 21st-century telecommunications and transport
systems, and the UK’s economy is increasingly dependent on satellitenavigation, with the GPS-sensitive portion of UK GDP being around
seven per cent – or about £100 bn in 2010 prices.
Applications
Transport
GPS, used for accurate navigation, is pervasive in our society, aiding
road, air, sea and rail transport, providing improved safety, and
optimised travel and planning. Satellite-navigation systems supporting
fleet management contributed £2.3 bn to GDP in the UK in 2010,
directly supporting 38,000 jobs and a further 48,000 jobs through
the supply chain. Satellite-navigation systems saved the UK aviation
industry £1.6 bn in 2010, by reducing delays, saving passenger time
and lowering emissions through more efficient network planning.
Precision-time measurements
With its very reliable time signal, the GPS system is used to provide a
very accurate measurement of time for terrestrial applications. Many
areas of huge economic importance are dependent upon the GPS
time signals – including financial services, computer systems, mobile
communication, security and energy supply. Global stock trading
1916 Albert
Einstein publishes
his general theory
of relativity.
1919 British
physicist Sir
Arthur Eddington
observes the
bending of
light rays, as
predicted by
general relativity.
60 I IOP Institute of Physics
1955 UK physicist
Louis Essen builds
the first reliable
atomic clock.
1960 The idea of
a multi-satellite
positioning system
for land forces
is proposed.
1978 The first
GPS satellite
is launched,
equipped with an
atomic clock.
Satellite Timing and Navigation
In 2010 the
satellite-navigation
industry made a
value-added
impact contribution
of around £113m
to UK GDP. It is
expected to
generate £1.45 bn
between 2011
and 2020.
June 2013 Physics: transforming lives
I 61
Satellite Timing and Navigation
depends on precise timing – with shares being sold and bought for
customers all around the globe, a fraction of a second of inaccuracy
could cost millions as share prices fluctuate. It has been reported
that a one-millisecond advantage in trading applications can be worth
$100 m a year to a major brokerage firm. Currently, electronic trading
comprises more than 80% of all trades. The routing of all internet traffic
packets is reliant on GPS timing.
Location-based services
GPS navigation systems are incorporated into vehicles and built into
mobile phones, expanding the potential of the GPS immensely. When
combined with internet services, it becomes a significant aid to society
and commerce, assisting the rise of personalised advertising services
that many business models now depend on. Search-and-rescue
operations also benefit substantially, as it can provide near real-time,
precise location information between rescue centres and people in
distress. It is estimated that the UK market size for location-based
services is set to reach around £4 bn by 2020.
Future
At the request of the European member states, including the UK, the
European Space Agency (of which the UK funds a €240 m annual
share of the budget) is currently constructing its own fleet of satellites,
named Galileo, to work alongside the existing American GPS, Russian
GLONASS and the Chinese Beidou systems. With the market for
satellite-navigation systems growing quickly, and becoming ever-more
interlinked with the provision of services on which quality of life, health
and safety depend, the need for an independent satellite-navigation
infrastructure is becoming more important by the day. Galileo will help
to guarantee the integrity of provision of such services in the future.
1993 The GPS is
fully operational,
giving worldwide
coverage.
2004 A GPS
navigation
system costs
less than £100.
62 I IOP Institute of Physics
2005 The first
Galileo satellite,
GIOVE-A, built by
Surrey Satellite
Technology
Limited, is
launched.
2008 GIOVE-B,
is launched.
2008 GPSenabled mobile
phones come
onto the market.
The UK has been awarded £794 m worth of contracts
associated with the Galileo project and stands to
significantly benefit from the estimated 100,000 jobs
that the programme is creating across the continent.
Galileo is to provide improved resolution on the current systems and is
expected to be accurate down to one metre, while current GPS has an
accuracy of around 10 m. It is expected that the system will reach initial
operational capacity by 2015, with the complete network at full capacity
before the end of the decade. The market worth of the Galileo project is
expected to be around €10 bn a year. The UK is playing a significant role
in Galileo. STFC’s RAL Space Department and Chilbolton Observatory
played a significant role in the first two test satellites which were both
constructed by UK companies in 2005 and 2008. This enabled UK
industry to build all 22 navigation/timing payloads for the operational
Galileo constellation.
The UK’s ongoing involvement in Galileo has generated significant
benefits for firms involved in both the provision and exploitation of
satellite-navigation technology. The UK has been awarded £794 m worth
of contracts associated with the validation and operational phases of
the Galileo project, and stands to significantly benefit from the estimated
100,000 jobs that the programme is creating across the continent.
Another Global Navigation Satellite System related project on the
horizon is the replacement of the satellites in the current FORMOSAT-3/
COSMIC mission, used to assist with weather forecasting. The British
company Surrey Satellite Technology Limited has been contracted to
provide up to 22 new satellites, the first of which is intended to be
launched in 2013, followed by the remainder through to 2018. The
satellites will carry an advanced receiver, and information about the
atmosphere will be collected by monitoring how it disturbs GPS signal.
With all of its applications, this technology will continue to have a
positive impact on the UK and global economy for many years into
the future.
2009 Global
Navigation
Satellite Systems
penetration in
mobile phones
worldwide
reaches 15%.
2011 Launch
of the first two
operational
satellites designed
to validate the
Galileo concept.
2012 Third and
fourth operational
satellites
launched, making
possible end-toend testing.
2020 Global
Navigation
Satellite Systems
penetration in
mobile phones
worldwide
expected to
reach 65%.
2020 European
Space Agency
Galileo navigation
system expected
to reach full
operational
capacity.
June 2013 Physics: transforming lives
I 63
Satellite Timing and Navigation
The British company
Surrey Satellite
Technology Limited
has been contracted
to provide up to 22
new satellites, the first
of which is intended
to be launched
in 2013, followed
by the remainder
through to 2018. The
satellites will carry
an advanced receiver
and information
about the atmosphere
will be collected by
monitoring how it
disturbs GPS signal.
Facts and figures
£113 m
value-added
impact contribution to UK GDP
by satellite-navigation industry
in 2010
£100 bn
GPSsensitive portion of UK GDP,
around seven per cent, in
2010 prices
86,000
jobs
supported directly and through
the supply chain by satellitenavigation systems supporting
fleet management
£794 m
value of
contracts awarded to the UK
associated with the validation
and operational phases of the
Galileo project
£4 bn
estimated to be
the UK Global Navigation Satellite
Systems market size for locationbased services by 2020
64 I IOP Institute of Physics
Case studies prepared by the Institute of
Physics in partnership with the Engineering and
Physical Sciences Research Council and the
Science and Technology Facilities Council
For further information contact:
Tajinder Panesor
76 Portland Place, London W1B 1NT
Tel +44 (0)20 7470 4800
E-mail Tajinder.Panesor@iop.org
www.iop.org
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Scottish Charity Register number SC040092
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