MIKES Metrology
TOPF
IVE
SPRING 2013
MIKES METROLOGY TOP 5
CONTENTS
SPIRIT OF THE GAME3
MIKES METROLOGY IN BRIEF4
EMRP – EUROPEAN METROLOGY RESEARCH PROGRAMME
6
SPECTROSCOPY 10
OPTICAL ATOMIC CLOCK
12
14
QUANTUM AMPERE
ENERGY HAR VESTING
16
18
ARCTIC METROLOGY
20
THE MIKES BUILDING
22
SPECIAL SER VICES
CENTRE FOR METROLOGY AND ACCREDITATION
Tekniikantie 1
FI-02150 Espoo
FINLAND
www.mikes.fi
The cover image was taken in the freight lift, able to transport weights of up
to four tons. It can, for example, be used to take large objects for measurement by the 3D-measurement machine underground.
Editorial board:
Veli-Pekka Esala, Thomas Fordell, Jussi Hämäläinen, Erkki Ikonen,
Jaana Järvinen, Petri Koponen, Monika Lecklin, Kaj Nyholm, Sari Saxholm
Cover image and layout: Jenni Kuva
Espoo 2013
2
MIKES METROLOGY TOP 5
SPIRIT OF THE GAME
Dear reader,
What did you do on the 12th of December last year?
The time 12:12:12 on 12.12.2012 was a once in a lifetime opportunity for all of us to do something different. I joined a meeting of geocachers of over 50
persons from all over Finland in front of the MIKES
building where the Finnish time is shown on a large
display. I do not belong to the group but happened
to pass by when the group watched the Finnish time
to show the magic numbers. The point here is how
the group used social media to arrange their meeting in an interesting place. Perhaps only one of them
knew beforehand, where the official time of Finland
can be seen – now all of them know. This was a small
step in a good direction to increase our conspicuousness.
Our strategy to be one of the top five metrology research institutes in selected fields in Europe has been
achieved. This might be an unexpected statement
from a Finn to say. However, this statement is based
on several items of proof. MIKES’ time is among the
most precise in the world. An extremely low noise
cryostat has been built. MIKES gives traceability to
northern Europe in length. Another topic in our
strategy is the special services for both national and
international customers. In practise, this means onsite
measurements in enterprises or research institutes local or abroad. Training is another subject of activity
in this field. Some of the research projects directly
or indirectly have produced equipment or software
programs. Typically these have strong metrology
background either through metrologically proofed,
outstanding measurement uncertainty values or long
used and thoroughly tested software for special use.
Some of these activities are shown on pages 18 and
19 of this magazine.
EMRP (European Metrology Research Programme)
has been of great interest to MIKES and Designated Institutes in Finland. The accompanied REGs (Researcher Excellence Grant) have been recognised. At
the moment there are 6 REGs in Finland. The last call
was of special interest for us. One indication was that
we hosted one of the three arranged EMRP partnering meetings in June 2012. Over 100 participants took
part in the meeting. The meeting was successful and
several good applications were initiated. Three of
the applications were written by MIKES, meaning in
practice that we will coordinate those three projects.
The total number of projects in which MIKES takes
part is 25 at the moment and 15 new will begin later
this year. The overall portion is 4 % of the whole programme. This number is almost double compared to
the percentage Finland gets from EU-funded research
projects. Several good results have been achieved in
the previous projects. Some of the results are shown
in this magazine.
In Finland the government wants to form bigger
units as a general goal. The municipal structure is
more effective, if the number diminishes to one third
of the current over 300 municipals. A single database
covering the whole healthcare system needs to be
built. In research, small units should be joined to bigger institutes. From MIKES’ point of view, our present
agility is in danger and more bureaucracy is foreseen.
A positive side also exists: metrology will be more
known and more used in everyday research, trade
and measurement as a whole.
Otaniemi in January 2013
Heikki Isotalo
MIKES METROLOGY TOP 5
3
MIKES METROLOGY IN BRIEF
ACOUSTICS TIME FR
ICITY
EQU
CTR
OW HUMID
ITY P ENCY
E L E AT U R E G A S F L
RES
PER
MASS FORCE TORQUE
SU
RE
TEM
LENGTH
Wa t e
r quality
Air quality
FMI
Optics
Ioni
s i n g r a d i a t i on
Ac
cele
Le
r a t i o n o f f re e
f al
l
ngt
h in geod e
sy
MIKES and Designated Institutes. MIKES = Centre for Metrology and Accreditation, FGI = Finnish Geodetic
Institute, FMI = Finnish Meteorological Institute, STUK = Radiation and Nuclear Safety Authority, SYKE = Finnish Environment Institute.
National Measurement System in
Finland
Finland has a slightly distributed metrology infrastructure. MIKES is
the National Metrology Institute and it acts as the National Standards Laboratory for most of the quantities. MIKES designates the
other National Standards Laboratories and Contract Laboratories.
MIKES Metrology overview
MIKES is a specialised research institute for measurement science
and technology. As the National Metrology Institute of Finland,
MIKES is responsible for the implementation and development of
the national measurement standards system and realisation of the
SI units in Finland.
The number of staff is 60 supported by MIKES administration and
few outsourced positions. The MIKES building is situated in the
city of Espoo and its branch office in Kajaani is the northernmost
National Standards Laboratory in the world. The high-quality laboratories provide the most accurate measurements and calibrations
– over 1600 certificates per year – in Finland.
MIKES also performs high-level metrological research and develops
measuring applications in partnership with industry. The activities
of MIKES aim to improve industrial competitiveness, the national
innovative environment, and public safety.
MIKES is a signatory to CIPM MRA (International Committee for
Weights and Measures, Mutual Recognition Arrangement) and a
member of EURAMET (European Association of National Metrology Institutes). Through international collaboration, MIKES is linked
to the international measurement system and to the European and
international metrology research community. MIKES takes actively
part in the European Metrology Research Programme (EMRP).
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MIKES METROLOGY TOP 5
Calibration and Measurement
Capabilities (CMCs) recorded in the
BIPM key comparison database, KCDB
Acoustics: 17
Length: 59
Time and frequency: 11
Thermometry: 39
Optics: 53
Mass and related quantities: 28
Electricity: 195
Ionising radiation: 30
Chemistry: 5
Total Finland: 437
Total all countries: 25330
Source: BIPM, 7 January 2013, kcdb.bipm.org
Voluntary peer review project
MIKES is a coordinator in the EURAMET TC-Q project Peer reviews
of Quality Management Systems (QMSs). The other partners in the
project are CMI (CZ), GUM (PL) and SMU (SK). The project supports
the evaluation and improvement of QMS processes and procedures
of the participating institutes. Learning from each other and sharing the best practice for QMS implementation are other goals of
the project. The QMSs of the institutes are based on ISO/IEC 17025.
A programme with on-site visits by peers is planned on an annual
basis and one or two fields in each institute are reviewed every
year. In 2012, the QMS of MIKES in the field of length metrology
was peer reviewed by an expert from GUM, and vice versa. Also
the humidity laboratory of MIKES was peer reviewed by a GUM
expert.
Year 2012 in numbers
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•••••• ARCTIC CIRCLE •••••••••
••••••••••••• Facts about ••••••••••••••••••••
••••••• Finland (12/2012) ••••••••••••••••
••••••••••••••••••••••••••••••••••••••••••••
•••• 5 428 570 inhabitants ••••
••••••• 338 430 km2 •••••••••••••
••••••••• Capital: Helsinki ••••••
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•••••••••••••••••••••••• KAJAANI ••
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• Land border with: Norway, Sweden, Russia •
••••••• Official languages: Finnish and Swedish •••••••••
•••••••••••• Currency: euro since 2002 •••••••••••••••••••••••••••••
•••• Gross domestic product: 180 • 109 € •••••••••••••••••••••••••••
•••••••• Biggest trade partners (export): SE, RU, DE, USA, NL •••••••••
•••••••••• R&D investments: 4.0 % of the GDP ••••••••••••••••••••••••••••••••••••
••••••••• Homeland of Angry Birds ••••••••••••••••••••••••••••••••••••••••••••••••••••••••
•••••• Standard & Poor’s grade AAA ••••••••••••••••••••••••••••••••••••••••••••••••••••••
•••• World record in mobile phone throwing 101.46 m ••••••••••••••••••••••••
•••• Most uncorrupted country in the world ••••••••••••••••••••••••••••••••••••
•••••• 188 000 lakes ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
••• 2 000 000 saunas •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
•••• 203 700 reindeer (Ministry decision)•••••••••••••••••••••••••••••••••
•••• Temperature variations: -51.5 °C … +37.2 °C •••••••••••••••••
••• National animal: bear ••••••••••••••••••••••••••••••••••••••••••••••
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•••• Source: Statistics Finland •••••••••••••••••••••••••••••••••
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HELSINKI •••••••
• ESPOO
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Total budget of MIKES was 11 M€ including MIKES
Metrology, FINAS (Finnish Accreditation Service)
and administration. FINAS is essentially self supporting and expenses of administration are divided
to Metrology and FINAS as a ratio of personnel.
Budget of MIKES Metrology alone was 7.5 M€ in
2012.
State budget 66 %
Calibrations 13 %
Research 17 %
Special services 3 %
Training 1 %
Proceeds.
Rent 33 %
Personnel expenses 40 %
SI-Maintenance 21 %
Support to other NSLs 3 %
Fees: BIPM, EURAMET, EMRP 3 %
Costs.
100
80
Theses (Dr., M.Sc.)
60
Domestic articles
MIKES publications
40
Conferences (articles, abstracts, talks, posters)
20
0
Peer reviewed publications
2009
2010
2011
2012
Publications.
MIKES METROLOGY TOP 5
5
EMRP
EUROPEAN
METROLOGY
RESEARCH PROGRAMME
EMRP is a metrology-focused European programme
of coordinated R&D that facilitates closer integration of national research programmes. It enables European metrology institutes, industrial organisations
and academia to collaborate on joint research projects within specified metrology fields.
The EMRP has been established under FP7 and it is supported
through Article 185 of the European Treaty. The EMRP is implemented by EURAMET e.V. (the European Association of National
Metrology Institutes), organised by 22 National Metrology Institutes (NMIs), and supported by the European Union.
The EMRP is jointly funded by the European Commission and the
participating countries with a total budget of 400 M€ over an approximately seven year period. It provides the opportunity for the
user community and other stakeholders to directly suggest topics
that the metrology community should address with its resources.
Additionally, researcher grant schemes will be available to bring
external expertise into the research projects, and there will be the
opportunities for organisations to participate in the research projects with their own resources where it is mutually beneficial to
do so.
The last call of the current EMRP is in 2013. Its topics are metrology
for energy and metrology for environment. A preparation of a
potential successor initiative of EMRP under Horizon 2020, called
EMPIR, is underway.
MIKES participation in the projects
(Details of five projects are presented on pages 6–9.)
Energy, 2010–2013:
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Characterisation of Energy Gases
Metrology for Energy Harvesting
Metrology for Smart Electrical Grids
Metrology for Solid State Lighting, Aalto University
Metrology for Improved Power Plants
Metrology for High-Voltage Direct Current
Environment and Metrology for Industry, 2011–2014:
•
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•
Metrology for Chemical Pollutants in Air
Emerging Requirements for Measuring Pollutants from
Automotive Exhaust Emissions
European Metrology for Earth Observation and Climate
Spectral Reference Data for Atmospheric Monitoring
SCATTEROMETRY
Metrology of small structures for the
manufacturing of electronic and optical devices
The dimensional metrology of sub-micrometer structures is very
important in semiconductor and optics industries. The constant
decrease in the size of the structures, however, sets remarkable
challenges to the reliability of the measurements.
Scatterometry is an optical method for determining parameters of
the structures on a surface by measuring the scattered light. The
method is widely used in semiconductor industry for process monitoring, but measurements are always relative and general standards are not available. This project will provide a scatterometry
reference standard for traceable and reliable measurements.
Within the project, also the applicability of scatterometry as a tool
MetEOC
European metrology for Earth
observation and climate
Remote monitoring of the Earth system is crucial to enable better
stewardship of the environment and most importantly to provide
the necessary information to aid policy makers in the development
of appropriate mitigation strategies to respond to climate change.
This must be tackled through global observations that can only be
made from space.
These space-based measurements need to be traceable and consistent to allow comparison with data gathered from other sources, e.g. ground-based monitoring stations, and to form a complete
picture. However, this is not the case at present.
This project will develop new standards and will validate the sensors used in satellites so that accurate, laboratory-quality measurements of climate parameters can be made from space.
6
MIKES METROLOGY TOP 5
•
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Metrology for Pressure, Temperature, Humidity and
Airspeed in the Atmosphere
Metrology for Radioactive Waste Management
Traceable Dynamic Measurement of Mechanical Quantities
Metrology to Assess the Durability and Function of
Engineered Surfaces
New Generation of Frequency Standards for Industry
Metrology for Ultrafast Electronics and High Speed
Communications
Metrology of Small Structures for Manufacturing of
Electronic and Optical Devices
Traceability for Surface Spectral Solar Ultraviolet Radiation
Metrology for Industrial Quantum Communication
Technologies
Metrology for the Manufacturing of Thin Films,
Aalto University
New Technologies and SI Broader Scope, 2012–2015:
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•
•
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Implementing the new kelvin
Accurate time/frequency comparison and dissemination
through optical telecommunication networks
High-accuracy optical clocks with trapped ions
Developing a practical means of disseminating
the new kilogram
Quantum ampere: Realisation of the new SI ampere
Traceability of sub-nm length measurements
Traceable measurement of mechanical properties of
nano-objects
Metrology with/for NEMS
Metrology of electro-thermal coupling for new functional
materials technology
Metrology for industry, SI Broader Scope and open excellence, 2013–2016:
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•
•
•
•
•
•
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Multidimensional reflectometry for industry
Traceable in-process dimensional measurement
Metrology for airborne molecular contamination in manufacturing environments (*
Single-photon sources for quantum technologies
Measurement and control of single-photon microwave
radiation on a chip (*
Quantum resistance metrology based on graphene
Automated impedance metrology extending the quantum
toolbox for electricity
International timescales with optical clocks
New primary standards and traceability for radiometry
Angle metrology
A quantum standard for sampled electrical measurements
Metrology for long distance surveying
Crystalline and self-assembled structures as length standards
Force traceability within the meganewton range
Metrology for moisture in materials (*
(* coordinated by MIKES
www.emrponline.eu
www.euramet.org
Courtesy of Nanocomp Oy Ltd
for characterisation of diffractive optical elements will be investigated and developed by MIKES in co-operation with University
of Eastern Finland and Finnish custom diffractive optical element
manufacturer Nanocomp Oy Ltd.
Diffractive elements split the incident laser beam into several or
numerous diffraction orders, which generate designable and even
very complex intensity patterns in the far field. Due to their versatile properties diffractive optics is becoming more and more important in the optics industry. However, fast, reliable and traceable
methods for component characterisation and quality control are
not currently available.
MIKES has designed and built an angular scatterometric measurement setup for measuring the intensities of diffraction orders with
high angular resolution. The diffraction pattern already reveals
how well the element reproduces the designed operation. In addition, by applying mathematical inversion methods into the measurement data, many dimensional parameters of the microscopic
structure can be obtained. Such detailed information about the
structures would be very useful for the manufacturer of diffractive
elements both for quality control and for monitoring and developing the fabrication process.
There has been little effort to validate radiation transfer (RT) models – upon which most practical Earth observation products are dependent – against SI traceable reference standards. State-of-theart RT models allow the interactions of solar radiation and matter
to be simulated for both man-made objects (e.g., optical sensors)
and natural environments (e.g., soil, plants, canopies, etc.). One of
the limitations of most canopy RT models is that the spectro-directional properties that are prescribed to objects (like the foliage,
wood and background elements of a canopy scene) are based on
simple mathematical models. Real targets exhibit more complex
scattering behaviour and cannot be matched accurately with the
existing parameterisations.
In this project, MIKES designs and constructs three-dimensional
targets to scope different aspects of real scenes. MIKES and Aalto
University characterise the targets mechanically and spectro-directionally to allow calculation of their spectral and angular reflectance using the RT models. Measured reflectance properties of the
targets will then be used to establish the traceability of the model
results to SI.
MIKES METROLOGY TOP 5
7
HVDC
Metrology for high voltage
direct current
Suitable sites for renewable energy generation are often remote,
for instance solar panels work best in deserts and wind turbines
work best offshore or in mountainous regions. The challenge is
getting electricity from these remote areas to where it is needed.
High-Voltage Direct Current (HVDC) offers a solution by enabling
power transmission along electricity ‘super highways’, and distributing energy thousands of kilometres away from where it was
generated.
HVDC provides low energy losses, enhanced grid stability and the
economically viable transmission of electricity, but until now no
metrology infrastructure has existed to support the technology at
the proposed 800 kV working levels. Consequently, it has not been
possible to measure reliably HVDC for operational or billing purposes, to monitor its quality and to determine energy losses.
Pylons of the HVDC Baltic Cable in Sweden. (Timberwind at the
German language Wikipedia)
Proper measurement of losses in HVDC systems is essential, e.g. in
converter stations, even relatively small loss reductions can translate in large-scale energy savings. The detection and improvement
of these small efficiency changes requires a step improvement in
precision of the power measurement on both a.c. and d.c. sides.
SmartGrid
Metrology for smart electrical
grids
As power generation becomes more decentralised, with increasing numbers of wind turbines and solar panels, the electricity grid
needs to evolve into a system capable of both giving and taking
back energy, known as a ‘smart grid’.
The current system distributes power outwards from a central
source to more and more remote areas, where electricity demand
decreases and infrastructure quality degrades. Today, these remote
areas are generating electricity from small-scale renewables, and
transmitting some of this back into the grid, along power lines not
designed to carry it.
Smart grids will solve this problem, but whilst the hardware re-
GAS
Characterisation of energy gases
EU aims to reduce its greenhouse gas emissions by 20 % before
2020. This together with the fact that natural gas resources in EU
are declining has increased the demand to use alternative energy
gases, such as biogas, to ensure a reliable and sustainable supply.
To enable gases from non-conventional sources to be used like
natural gas, without any modification to existing equipment, the
measurement infrastructure needs to be developed in order to
characterise these gases.
The current standards of measurement for natural gas will be tested for their suitability at measuring the properties of the alternative gases. Important measurements include gas composition, calorific value (energy content) and humidity, which are all needed to
ensure efficient trade, safe use and transportation. Certain known
impurities, such as ammonia and siloxanes, also need to be measured and closely monitored as they can cause problems during gas
processing and use.
Fusing together gas pipes., Gasum Oy.
8
MIKES METROLOGY TOP 5
Especially, d.c. voltage measurement at very high voltage in convertor substations has not been sufficiently accurate for metering
purposes or for loss determination. Work is performed to provide
measurement infrastructure for on-site calibration of wide-band
d.c. dividers installed in converter stations, as well as for industrial
laboratory references, to provide traceability. The target voltage
has been raised to an unprecedented 1 MV to prepare for expected increase in future HVDC schemes.
MIKES is responsible of a work package, where a new type of accurate and transportable reference divider with a unique combination of d.c. and a.c. performance is developed. Transportability is
assured by having it in modules of 200 kV each, and stackable up
to 1000 kV. It will be used to provide traceability on-site in manufacturer’s laboratory.
A first production unit (200 kV) of a modular divider has been
manufactured. It is housed in a gas-tight envelope to ensure stable
conditions for the resistor elements. The first test results are encouraging: they ensure the ability of the divider to act as a reference for d.c. voltage with uncertainty below 100 V/MV, at the same
time providing bandwidth of more than 10 kHz.
Potential distribution
quired to implement them is available, the theoretical and practical knowledge required to ensure their stability is not. This project
aims to improve the accuracy of on-site measurements, vital for
maintaining the quality of electricity supply and guaranteeing fair
trade of energy.
In this project, a metrological measurement infrastructure will be
developed to support successful implementation of a Smart Electrical Grid in Europe. The research will provide essential support to
ensure security of electricity supply and grid stability, grid quality, and fair trade between commercial parties employing the grid.
The objectives of the project include: a measurement framework
for monitoring stability of smart grids, traceable on-site energy
measu-rement systems for ensuring fair energy trade, remote onsite measurement of power quality and efficiency, and modelling, simulation and network analysis of the system state of smart
grids. MIKES has developed an algorithm with which Automated
Meter Reading (AMR) data can be used for verification of customer
electricity meters. The method can also be used for determination
of meter errors by analysing AMR data, without need for interruption of service or access to the meter.
MIKES task in the project is to study experimentally the behaviour
of water vapour in methane and to determine improved calculation method for an enhancement factor required in measuring
humidity and moisture content of energy gases. For this purpose,
MIKES developed a novel research facility in which gas pressure
is controlled in the pressure range 0,1 MPa to 7 MPa (1 bar to 70
bar) and dew-point temperature range between -50 °C and 15 °C.
In tests with air-water vapour mixture the uncertainty level of 1 %
was achieved in determining the enhancement factor.
Traceable mass flow measurements of methane and liquid water
are essential in the research facility. Therefore, MIKES developed a
novel calibration method for nanoscale liquid flow rates enabling
calibrations down to below 100 nl/min. A static weighing method
was developed and applied for calibrating a mass flow controller
(MFC).
MIKES METROLOGY TOP 5
9
SPECTROSCOPY
Text: Mikko Merimaa, Thomas Fordell, Kaj Nyholm, Toni Laurila, Albert Manninen
Photos: Mikko Merimaa, Toni Laurila, Albert Manninen
From left to right: Ville Ulvila (Helsinki University), Mikko Merimaa, Albert Manninen, Craig Richmond, Guillaume Genoud, Tuomas
Hieta and Toni Laurila (MIKES & Aalto University).
Time and frequency – the foundation of spectroscopy
Over the last few years MIKES has devoted an increasing amount of resources to research and development of spectroscopic techniques. This strategic
move is motivated by the increasing importance of
and tightened requirements for emission control
and environmental monitoring.
High-precision metrology
Near-infrared: frequency synthesis & optical frequency
standards
Mid-infrared: frequency synthesis & spectral atlas
A frequency comb generator realises a comb of densely spaced
spectral lines, the frequency of each being traceable to the very
definition of the unit of time. As such, the frequency comb enables ultra-precise frequency synthesis in the near infrared. Spectroscopy with a directly synthesised near-infrared frequency at
the important 1.5 μm telecom band was recently demonstrated
at MIKES. The synthesised frequency range will now be extended
to mid-infrared using optical parametric oscillators.
In an optical parametric oscillator (OPO), an incoming pump beam
generates in a nonlinear crystal two beams: a signal and an idler.
When the pump and the signal are phase coherently locked to a
frequency comb generator, the frequency of the idler is also traceable to the primary frequency standard. Furthermore, if the wavelengths of the signal and pump are almost degenerate, the idler
will be in the mid-infrared. This method to synthesise mid-infrared
light will be applied to determine an accurate atlas of molecular
spectra in the mid-infrared region and to precise trace gas detection.
Gas-filled hollow-core photonic crystal fibres sealed to conventional optical fibres enable the construction of highly stable allfibre optical frequency standards using Doppler-free saturation
spectroscopy. In an EMRP project, MIKES develops a new generation of robust, compact and turn-key optical frequency standards
based on hollow-core photonic crystal fibres for the near-infrared
with a fractional accuracy of better than 10−10. The operating
wavelengths will be targeted on industrial applications. Especially, high-precision standards at 1.55 µm are important tools in
telecommunications.
10
Spectroscopy studies the interaction between matter and radiated
energy as a function of its frequency. Today, time and frequency
are the two quantities that can be measured the most accurately.
Measurements of the highest precision must be traceable to the
primary frequency standards. MIKES atomic clocks realise a microwave frequency at an accuracy better than 10-14, and this signal can
be transferred phase coherently to the visible and near-infrared
domain using frequency comb generators and to the mid-infrared
using optical parametric oscillators.
MIKES METROLOGY TOP 5
Within the framework of EMRP, a consortium was established to
improve the quality of spectral databases, especially by measuring
molecular absorption using state-of-the-art Fourier transform infrared spectrometers. In collaboration with the Laboratory of Physical Chemistry at the University of Helsinki, MIKES will contribute
by providing accurate frequencies for a set of selected reference
lines using optical single-frequency synthesis in the mid-infrared
between 2.7 μm and 3.5 µm. The targeted molecules are methane
and nitrous oxide.
Spectroscopy for the industry
and the environment
Hyperspectral remote sensing using supercontinuum light
Real-time monitoring of metals in liquid flows
Real-time monitoring of metal concentrations in liquid flows would
be highly desirable in applications like environmental pollution
monitoring, waste water treatment and industrial process control.
However, feasible instrumentation capable of real-time measurements down to sub-mg/L concentration level is not currently available. In collaboration with the University of Oulu (CEMIS-Oulu)
and six industrial partners MIKES has developed a compact and
robust metal analyser employing micro-plasma emission spectroscopy (MPES). In the core of the analyser is an integrated ceramic
chip with laser machined microfluidic channel and tungsten metals
such as Mn and Ag in real-time at mg/L concentrations in flowing
samples. The long-term intensity fluctuations of the emission signals have been reduced to 6–7% by accounting for the temperature variations of individual plasma discharges.
A setup for real-time
monitoring of metal
concentrations in liquid
flows.
Together with the Technical Research Centre of the Finnish Defence Forces and an industrial partner, MIKES has developed an affordable infrared supercontinuum source for hyperspectral remote
sensing. The setup was recently tested in the field at measurement
distances up to 250 m. The approach has good potential for spectrally resolved remote sensing applications and active illumination
of targets for hyperspectral imaging.
Field tests of hyperspectral remote sensing.
Quantum cascade lasers for industrial gas sensing
Radiocarbon monitoring for safe disposal of nuclear waste
Cavity ring-down spectroscopy (CRDS) is one of the most sensitive
spectroscopic techniques. In a recently started EMRP project MIKES
will apply mid-infrared CRDS to monitor radiocarbon emissions
from nuclear waste burial sites. The theoretically calculated detection limit in a pure carbon dioxide sample is below the abundance
of radiocarbon in atmospheric carbon dioxide, which is one part
per trillion (10–12)
4
Together with an industrial partner, MIKES is developing a midinfrared gas sensor for industrial applications. The sensor under
development is based on a quantum cascade laser (QCL), a technology that has only recently become sufficiently mature for industrial applications. Collaboration with a QCL manufacturer has
given MIKES a unique opportunity to work with pre-production
prototypes individually manufactured for the desired wavelength.
The sensor under development targets sulphur compounds. Detection limits below one part per billion (10–9) have been demonstrated.
Recent publications
3
5
6
2
6
7
9
1
2
8
K. Blomberg von der Geest, J. Hyvönen, T. Laurila, Real-time determination
of metal concentrations in liquid flows using microplasma emission spectroscopy, Proceedings of the Global Photonics Conference 2012, 13–16 Dec
2012 Singapore.
M. Vainio, M. Merimaa, L. Halonen, and K. Vodopyanov, Degenerate 1 GHz
repetition rate femtosecond optical parametric oscillator, Opt. Lett. 37,
4561–4563 (2012).
S.-S. Kiwanuka, T.K. Laurila, J.H. Frank, A. Esposito, K. Blomberg von der
Geest, L. Pancheri, D. Stoppa, and C.F. Kaminski, Development of Broadband
Cavity Ring-Down Spectroscopy for Biomedical Diagnostics of Liquid Analytes, Anal. Chem. 84, 5489–5493 (2012).
M. Vainio, M. Merimaa, and L. Halonen, Frequency-comb-referenced molecular spectroscopy in the mid-infrared region, Opt. Lett. 36, 4122–4124
(2011).
M. Vainio, M. Siltanen, J. Peltola, and L. Halonen, Grating-cavity cw optical
parametric oscillators for high-resolution mid-infrared spectroscopy, Appl.
Opt. 50, A1–A10 (2011).
A schematic of the planned CRDS setup for carbon isotope analysis.
MIKES METROLOGY TOP 5
11
OPTICAL ATOMIC CLOCK
Text: Thomas Fordell, Mikko Merimaa, Thomas Lindvall, Kaj Nyholm
Photos: Jenni Kuva, Anders Wallin, Thomas Legero
From left to right: Anders Wallin, Thomas Fordell, Markku Vainio, Mikko Merimaa, Thomas Lindvall and Ilkka Tittonen (Aalto University).
Time and frequency are the two quantities that can
be measured the most accurately, and the unit of
time is considered the most fundamental base unit.
Other units, such as the meter and the electrical
units are either defined or realized from the second
and the fundamental constants of physics. In 2015
the General Conference on Weights and Measures
(CGPM) is likely to update the International System
of Units and will possibly define all base units, including the kilogram, in terms of the second and
fundamental constants. However, before the second
itself can be redefined in terms of an optical transition, many different solutions must be explored and
compared to each other as well as to conventional RF
atomic clocks.
Time and frequency metrology is going through the greatest changes since the first demonstration of the caesium atomic
clocks in the 1950’s. This revolution is caused by the arrival of optical atomic clocks, the development of which was sparked by the
demonstration of self-referencing femtosecond frequency comb
technology in 2000. In essence, frequency combs make it possible
to count optical cycles. The potential for great performance improvements over caesium atomic clocks have been known for a
long time, but it was not until suitable clockwork was found that
considerable progress was made. Today, several groups already report fractional uncertainties down to 10–17, thus beating the best
caesium clocks by an order of magnitude.
The unit of time is considered the most fundamental base unit.
Thus, the development of optical clocks is expected to have widespread impact on science and our daily lives; however, before that
happens, several technological and fundamental challenges must
be overcome. A clear challenge is to develop more accurate methods to compare the frequencies of existing optical clocks, which
are scattered around the world. Such comparisons of optical clocks
at the highest level will tremendously improve the case for future
redefinition of the second.
The objective of the research at MIKES is to develop a transportable optical clock, that is, a compact combination of control electronics, physics package, and optical frequency counting. For this
purpose collaboration between MIKES and research groups at the
Aalto University has been established.
Principle of an optical single-ion clock. A single ion is captured in
a radiofrequency trap by photoionisation of an atomic beam. The
captured ion is then laser cooled to a few millikelvins, after which
an extremely stable laser probes the frequency of a reference transition in the ion. The reference transition is chosen such that the
transition linewidth is very narrow; in the case of 88Sr+ it is only 0.4
Hz. A frequency comb is then used to make a phase coherent leap
from the optical domain (1015 Hz) to the radiofrequency domain
(109 Hz) of electronics. In essence, the frequency comb makes it
possible to count optical cycles. In the case of 88Sr+, one second has
elapsed when 444 779 044 095 484 oscillations have been counted.
12
MIKES METROLOGY TOP 5
In an ideal atomic clock the reference atoms are at rest in free
space without interacting with each other or the outside world.
To reach an approximation of such an ideal situation, the atoms or
ions in optical clocks are trapped and cooled to temperatures close
to the absolute zero. Optical clocks can be broadly categorised in
two groups: clocks based on single laser-cooled ions in RF-traps
and clocks using an ensemble of neutral atoms in an optical lattice.
An ion clock is perhaps the best approach for a transportable optical clock as technical complexity and the size of the physics package must be minimised. The low optical power required in an ion
clock also greatly simplifies the overall design. The requirement of
simplicity is perhaps best fulfilled in an optical clock based on a single trapped and cooled 88Sr+ ion that has a simple alkali-metal-like
energy level structure. For these reasons, the single-ion 88Sr+ clock
was chosen as the candidate for the transportable optical clock at
MIKES.
Current status of the project
An endcap ion trap has been designed in collaboration with the
National Research Council of Canada (NRC). The figure to the right
shows a photograph of the trap electrodes. The inner endcap electrodes have a diameter of 0.5 mm and the outer shield electrodes
have an outside diameter of 2 mm. The clock laser reference cavity,
shown in the figure below, has been designed and assembled in
collaboration with the Physikalisch-Technische Bundesanstalt (PTB)
in Germany. The vacuum enclosure and thermal shields for the cavity are currently being designed, also in collaboration with PTB.
The ion clock requires light at six different wavelengths, ranging
from 405 nm to 1092 nm for photoionisation of neutral Sr, for cooling and state preparation of the Sr+ ion and for probing the clock
transition. These light sources are currently being built and tested.
A commercial fiber-based frequency comb will be used to measure
the optical frequency of the clock laser and to frequency stabilise
some of the lasers.
In parallel with constructing the experimental setup, theoretical
work on dark state suppression and optimisation of laser cooling
and fluorescence in a trapped ion has been carried out. The theoretical simulations were compared to experimental data obtained
at NRC.
The MIKES endcap trap. A single Sr+ ion will be captured and
cooled between the electrodes. The trap is based on a design by
Alan Madej (NRC, Canada). The distance between the electrodes
is 0.56 mm.
As a novel way to avoid dark states from forming, we have recently proposed the use of an unpolarised, incoherent light source to
drive the repumping transition in the 88Sr+ ion. Such a light source
will be especially suitable for transportable clocks and space clocks.
Recent publications
T. Lindvall, T. Fordell, I. Tittonen, and M. Merimaa, Unpolarized, incoherent
repumping light for prevention of dark states in a trapped and laser-cooled
single ion, Phys. Rev. A, accepted for publication (2013).
T. Lindvall, M. Merimaa, I. Tittonen, and A. A. Madej, Dark-state suppression
and optimization of laser cooling and fluorescence in a trapped alkalineearth-metal single ion, Phys. Rev. A 86, 033403, (2012).
In collaboration with
Micro and Quantum Systems Group
The Micro and Quantum Systems (MQS) group is part of the Department of Micro and Nanosciences at Aalto University. It has access to state-of-the-art cleanroom facilities. Research topics include
development of nanofabrication techniques using such methods
as atomic layer deposition, electron beam lithography, focused ion
beam processing and cryogenic deep reactive ion etching, as well
as nanoelectromechanical systems devices for high-precision sensing. The group is also working with atom and quantum optics:
laser cooling and trapping and optical pumping of atoms.
Metrology Research Institute
The Metrology Research Institute (MRI) of Aalto University operates under the Finnish name MIKES-Aalto Mittaustekniikka as the
Finnish national standards laboratory for optical quantities. The
research topics include radiometry in the development of singlephoton sources and single-photon detectors, associated with such
technologies as quantum computing and quantum cryptography
and improving reliability of few-photon measurements through a
robust link to classical intensity measurements.
Reference cavity for the clock laser. Fused silica mirrors are separated by a 30 cm long spacer made of ultra-low expansion glass.
The cavity will be put under vacuum, and heavily shielded from
thermal, mechanical and acoustic noise. The cavity has been designed in close collaboration with PTB, Germany.
MIKES METROLOGY TOP 5
13
QUANTUM AMPERE
Text: Antti Kemppinen, Kaj Nyholm, Antti Manninen
Photos: MIKES archives, Heikki Isotalo
Emma Mykkänen assembling the MIKES cryostat.
In the coming years, the SI system of units is likely
to undergo the most comprehensive revision since
its introduction 50 years ago. Four base units out of
seven, kilogram, mole, kelvin, and ampere, will be
redefined in terms of fixed values of fundamental
constants: Planck constant h, Avogadro constant
NA, Boltzmann constant kB, and elementary charge
e, respectively. MIKES has an important role in this
ambitious plan, especially in developing a quantum
standard for current, which would be a direct realisation of the new ampere based on a fixed value of e.
Currently, MIKES in collaboration with O. V. Lounasmaa Laboratory (OVLL) of the Aalto University is developing the hybrid turnstile, discovered at OVLL, which is based on both superconducting and normal-metal elements. The hybrid turnstile is one of the
most promising candidates for a quantum current standard. The
development of the turnstile, especially parallelisation, is part of
the project “Quantum ampere” of the EMRP, which continues
the work of REUNIAM. At MIKES the turnstile is also developed
in Antti Kemppinen’s postdoctoral researcher project “Quantum
standard for the new ampere” funded by the Academy of Finland.
The natural quantum standard for electric current would be a
device transporting single electrons with a frequency f traceable
to atomic clocks, thus generating the current I = ef. This can be
achieved by so-called Single Electron Tunneling (SET) devices –
known as SET pumps or turnstiles – which generate electric current by moving one electron at a time. Already in the 1980s, such
devices were proposed together with a suggestion that the quantized current should be compared to the quantum standards of
voltage (Josephson effect) and resistance (quantum Hall effect) via
the Ohm’s law. This experiment, called quantum metrology triangle, would enhance the knowledge of fundamental constants and
has been one of the major goals of metrology ever since.
14
In the past few years, single electronics has experienced a renaissance. New interesting ideas such as the hybrid turnstile, the
single-parameter semiconducting nanowire pump, and quantum
phase slips in superconducting nanowire, have been proposed and
experimentally investigated. They have raised the hope to increase
the current to the level above 100 pA. Part of the recent progress
can be attributed to the EMRP project REUNIAM (2008–2011) in
which MIKES collaborated with the largest National Metrology Institutes (NMIs) of Europe.
MIKES METROLOGY TOP 5
Scanning electron micrograph of a parallel connection of several
hybrid turnstiles, which is a promising candidate for a quantum
standard of electric current. Its basic element is the single-electron
transistor consisting of superconducting leads and a normal-metal
island (bottom left).
generated at higher temperature parts of the setup. Its effectiveness has been demonstrated by a record-low measured density of
quasiparticles in a superconductor. The careful shielding has also
made possible trapping of electrons in a specific position of the
sample for more than 10 hours. In a cryostat with conventional
shielding, this hold time in the same sample was only about 20
seconds. The improved control of single electrons decreases the
error rate of the turnstile significantly. On the other hand, the sensitivity of the hybrid turnstile to microwaves can be applied in microwave detection. That will be developed in a new EMRP project
MICROPHOTON (2013 – 2016) which will be coordinated by MIKES.
Recent publications
Charge detector signal of a hybrid turnstile -based single-electron
trap as a function of time. The two levels correspond to two
charge states which differ by a single electron. In (a) the control
parameters are adjusted to allow frequent transitions of the
charge state, and in (b) the parameters are adjusted for maximum hold time of electrons.
The ultimate objective of the research is a quantum current standard that can be used in the closure of the quantum metrology triangle. The experiment will be implemented at MIKES by applying the
quantized Josephson voltage over a resistor calibrated against the
quantum Hall resistance standard, and by comparing the resulting
current against the hybrid turnstile. Achieving this goal requires
quantized current exceeding 100 pA with relative uncertainty below 10-7. MIKES and Aalto have already demonstrated quantized
current of more than 100 pA using 10 turnstiles in parallel, and the
main problems that have limited relative uncertainty to about 10-4
are now understood and partly solved.
J. P. Pekola, O.-P. Saira, V. F. Maisi, A. Kemppinen, M. Möttönen, Y. A. Pashkin,
and D. V. Averin, Single-electron current sources: towards a refined definition of ampere, arXiv:1208.4030, submitted for publication (2012).
V.F. Maisi, S.V. Lotkhov, A. Kemppinen, A. Heimes, J.T. Muhonen and J.P. Pekola, Single quasiparticle excitation dynamics on a superconducting island,
arXiv:1212.2755, submitted for publication (2012).
O.-P. Saira, A. Kemppinen, V. F. Maisi and J. P. Pekola, Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor, Phys. Rev. B 85,
012504 (2012).
A. Kemppinen, S. V. Lotkhov, O.-P. Saira, A. B. Zorin, J. P. Pekola and A. J.
Manninen, Long hold times in a two-junction electron trap, Appl. Phys. Lett.
99, 142106 (2011).
V. F. Maisi, O.-P. Saira, Yu. A. Pashkin, J. S. Tsai, D. V. Averin and J. P. Pekola,
Real-Time Observation of Discrete Andreev Tunneling Events, Phys. Rev. Lett.
106, 217003 (2011).
In collaboration with
O. V. Lounasmaa Laboratory at Aalto University
The main collaborator in this work is the PICO Group lead by prof.
Jukka Pekola. The group investigates mesoscopic physics and its
sensor applications. The main focus is on charge transport and
thermal properties of metallic and superconducting nano- and
microstructures. The group invented the hybrid turnstile and has
been the leading team in the research on it. It has access to a clean
room with state-of-the-art facilities, suitable for the fabrication of
nano-electronic devices.
VTT Technical Research Centre of Finland
MIKES has a long history of collaboration with VTT, especially in
the field of quantum standards for electricity. In this work, VTT’s
main role is development of Josephson voltage standard and null
detector for the quantum metrology triangle.
The quantum metrology triangle: The triangle experiment yields
a consistency check for the fundamental constants e (elementary
charge) and h (Planck constant) and for the quantum standards
of electric current, voltage and resistance.
A major limitation for the performance of hybrid turnstiles and
many other superconducting devices, e.g., quantum bits, is caused
by microwave-generated quasiparticles (nonsuperconducting electrons) in the superconductor. For this reason, the sample chamber
in MIKES’s cryostat has been shielded and filtered with extensive
care to protect the hybrid turnstile from thermal noise photons
Qu-Ampere consortium
Joint Research Project Qu-Ampere (Quantum ampere: Realisation
of the new SI ampere) of EMRP started in 2012 and will last for 3
years. It is coordinated by PTB, and other NMI partners are MIKES,
NPL, and LNE. The project aims at developing the practical implementation of the new ampere definition based on semiconducting
single-electron pumps and on the hybrid turnstile.
MIKES METROLOGY TOP 5
15
ENERGY HARVESTING
Text: Ossi Hahtela, Kari Ojasalo and Jaani Nissilä
Photos: Ossi Hahtela and Heikki Isotalo
Energy efficiency and sustainable energy sources are
of great importance in developing modern and future technologies. At present the energy efficiency
of most machines, industrial processes and power
plants is very poor. Many devices are powered by
batteries that need to be charged and replaced regularly. Energy harvesting processes capture energy
that would otherwise be lost as heat or movement.
Energy harvesters convert wasted energy into electrical form that can be used for charging batteries or
directly running electrical devices, sensors, actuators,
transmitters etc.
Energy harvesting has gained increasing interest during the last
years. It offers extensive possibilities to improve energy efficiency,
reduce emissions and dependence on batteries and also cut operating costs of devices and processes. Many significant industries
such as mobile communication, instrumentation, transport, automotive and construction have already started studying the potential of energy harvesting devices. Although wasted energy is
abundant in most human related activities, an efficient and cost
effective capturing of the waste heat or mechanical vibrations in a
reasonable scale has been a challenge. In addition, the lack of accurate and standardised measurement methods has hindered the
development and reliable comparison of different materials and
devices. At present, MIKES is involved in three research projects
aiming to provide and improve measurement techniques for enhancing thermoelectric energy harvesting. Project partners include
several European National Metrology Institutes, Aalto University,
VTT and industrial companies.
16
MIKES METROLOGY TOP 5
Figure-of-merit of thermoelectric materials
Temperature gradients in thermoelectric materials create electrical
potential which can be used for electrical power generation. The
performance of the energy conversion in thermoelectric materials
is typically characterised using dimensionless figure-of-merit, ZT,
parameter. Figure-of-merit is defined as ZT=S2σT/κ, where S, σ, T
and κ are the Seebeck coefficient, the electric conductivity, the absolute temperature and the thermal conductivity, respectively. ZT
can be measured directly or by first determining the different material parameters S, σ, and κ separately. Uncertainty in determining ZT is typically very large but comparing the ZT values obtained
using different measurement methods can help ensuring reliable
results.
Improving the ZT of traditional semiconducting thermoelectric
materials e.g. by doping has limitations because the Seebeck coefficient, thermal conductivity and electrical conductivity cannot
be modified independently in bulk materials. However, nanotechnologies such as exploiting of thin-films and nanopowders offer
interesting possibilities to enhance energy conversion efficiency of
thermoelectric devices because the key material parameters can be
tailored more individually in nanostructured materials.
New sustainable thermoelectric materials are needed e.g. to replace widely used telluride alloys (Bi2Te3, Sb2Te3) which are expensive, scarce and hazardous to environment. Research groups at VTT
and Aalto University are developing new micro- and nanostructured thermoelectric materials using novel thin-film fabrication
(ALD), spark plasma sintering (SPS), thermal spray (DWTS) and direct printing (nScrypt) methods. The thermoelectric properties of
these materials will be tested and characterised at MIKES.
Accurate and reliable determination of ZT is a necessity in developing new thermoelectric materials and therefore also in growing
commercial potential and market acceptance of thermoelectric devices. MIKES is developing a Harman measurement setup for direct
ZT measurements in the temperature range from 20 °C to 650 °C.
In Harman method an electric current step is applied through the
material of interest and ZT is determined from the resulting voltage response across the material. The setup is designed so that it
can also be used for determining the Seebeck coefficient and the
electrical conductivity. A need for high temperature measurement
techniques of thermoelectric properties can be found e.g. in combustion engine and power plant industries for improving energy
efficiency and emission reduction.
A probe and borofloat glass test sample for high temperature
thermal conductivity measurements.
Thermal conductivity measurements
Thermal conductivity is a crucial parameter for the design of thermoelectric generators. Thermal conductivity of thermoelectric
materials is typically very low, on the order of 1 W/(m·K), which
makes accurate determination of the thermal conductivity difficult
especially at high temperatures. MIKES has developed a measurement system based on a 3ω method for the thermal conductivity
measurements in the temperature range from 20 °C to 630 °C. 3ω
method is an ac-technique that can be used for both bulk and thinfilm samples.
At MIKES, the thermal conductivity measurements are performed
in a horizontal three-zone tube furnace which provides accurate
and uniform temperature control. The sample space can be evacuated to vacuum or alternatively a protective argon gas environment can be applied to prevent undesired oxidation of the sample
material at high temperatures. Test results indicate that a measurement accuracy better than 10 % can be achieved which is a very
good result for high temperature thermal conductivity measurements.
Temperature dependence of the thermal conductivity of several
materials was determined using 3ω technique.
Thermoelectricity research at low temperatures
Besides utilising waste heat for energy recovery at high temperature processes, many interesting thermoelectric energy harvesting
applications can be found at room temperature and below. Measuring physical properties of new thermoelectric materials at low
temperatures may help considerably when aiming at optimising
ZT. MIKES has acquired a new closed-cycle helium cryocooler which
allows varying the sample temperature between 4 K and 325 K.
The refrigerator is a so-called pulse tube cryocooler and being
equipped with a special low vibration option. We expect very low
mechanical vibration levels and thereby accurate measurements of
thermoelectric properties should be feasible. The design of the cryostat is at the final stage and first measurements will be performed
in early spring 2013.
3ω technique can be used to measure the thermal conductivity of
both bulk and thin-film samples.
MIKES METROLOGY TOP 5
17
SPECIAL SERVICES
Text: Sari Saxholm
Photos: MIKES archives
f2p
Green comb
f2s
λ p/2
KTP
2x1 coupler
λp
PZT
Pump
1064nm
NIR comb
λ s/2
Ti:sapphire OFC
~ 1 GHz rep.rate
locked to an H-maser
(Kvarz CH1-75A)
λp
CW OPO
M3
M4
Photodetector
λi
M1 MgO: M2
PPLN
λp &λ s
CH4 spectrometer
CH4-cell (50 cm, 30 mTorr)
Pinhole CaF2 wedge
MIKES offers targeted services for special needs of research and industry
– at MIKES or on site
MIKES precision measurements at industrial sites
Take care of your traceability chain – plan, act, calibrate!
In industry there are various devices, which cannot be transferred
for calibration due to their size, precision or other property. MIKES
carries out traceable on-site calibrations and measurements of
measuring devices and equipment. Traceability means an unbroken chain of comparisons, all having stated uncertainties. This
ensures that a measurement result or the value of a standard is
related to references at the higher levels, ending at the primary
standard. MIKES calibrates on-site e.g. different measuring devices
of length, force and torque as well as of electrical quantities.
Creating a calibration system for a company is a cooperation project, where MIKES can offer assist and training services. During a
project, items, e.g. which instruments should be included in the
calibration program, realisation of traceability, needed level of
uncertainty, needed calibration instructions as well as other quality documentation and their maintenance need to be decided and
clarified.
Assuring precision of machine tools
Liable measurements need measurement uncertainty
Demands of production and quality systems require knowledge on
the precision of machine tools. Different measurements are performed on machine tools during e.g. acceptance inspection. The
most important measurements are spindle run out, the parallelism
between the spindle and the machine, perpendicularity measurements, and straightness and perpendicularity measurements of
machine movements. Additionally, machine-tooling tests are used
to find out the precision of the machine in operation.
MIKES is offering training and consultation services for measurement uncertainty evaluations. Participants will learn basics about
measurement uncertainty evaluation and will get ideas how to apply these methods into their own cases. Tailored training courses
corresponding to the customer needs are offered, too. These concentrate to customers cases with their initial information. Scope
and contents are always agreed with customer. Also plain measurement uncertainty calculation services are available.
Evaluation of measurement system with RR-tests
High precison measurements for high voltage
RR tests are internationally accepted test measurements of a specified form. The name RR stands for repeatability and reproducibility. As its name implies, RR test reflects the magnitude of stochastic
errors in measurements. RR test reveals the variance (“uncertainty”) of the measuring system by using simple experimental measurement setup. The test helps to find out if a measuring device
or a process is good enough to measure if given tolerances are
satisfied, and if a possible fault is caused by the measurer or the
measuring device.
High voltage measuring systems can be calibrated up to voltages
from 200 kV to 400 kV using direct comparison with a reference
system. In addition, an on-site linearity verification of these systems can be performed up to their highest voltage. In the case
of impulse quantities, low voltages and currents are also covered.
Consultation services are offered: The measuring system of a client
can be evaluated and on-site calibrations can be performed.
Interested? Please contact our Customer Service Manager
Veli-Pekka Esala, Veli-Pekka.Esala@mikes.fi
18
MIKES METROLOGY TOP 5
CASE: Three direct-current voltage dividers were calibrated jointly
by MIKES and Aalto University. Measurements were performed at
Aalto University high voltage laboratory and the traceability of
the measurements was ensured by MIKES. Future plan for these
devices is measurement of energy transferred from one country
to another.
for modern research and industry
Tools based on solid metrology have been developed over the years in
research projects, for industry needs or for own use
Humidity calibration systems
AC measurement software in VEE
Cost effective maintenance of humidity measuring instruments is
often difficult to achieve due to time consuming calibration procedures. MIKES is experienced in designing and constructing humidity calibration systems for laboratory and industrial applications
at various accuracy levels according to the customer needs. With
these systems customers have significantly improved the reliability
and efficiency of their calibration work. The traceability of the calibrators is easily obtained through MIKES’ worldwide recognised
calibration service.
High precise AC voltage measuring software up to 500 Hz was developed for Agilent 3458A multimeter. The software controls one
or two Agilent 3458A meters, which are used in high resolution
DC sampling mode. Sampling frequency is adjusted according to
signal frequency, which is not assumed to be stable. Simultaneously measured quantities are AC peak voltage (IEC 60060), rms
and frequency. The software can also be used for DC voltage and
ripple measurements.
An ultra stable dual-DAC voltage source
Impulse measurement software
When developing a quantum standard for AC voltages in audio
frequencies, an ultra-stable high-resolution voltage source has
been developed. The voltage stability in the range of 1 V – 5 V in
frequency band 1 Hz – 20 kHz is better than 1 ppm, exceeding the
performance of commercial calibrators. A technology transfer project to AIVON Oy has been started to commercialise a dual version
of this source, where two independent voltage outputs are referenced to a single Zener voltage reference. The voltage ratio of the
two channels is stable even down to 0.2 ppm allowing various new
measurement applications to pop up.
A compact software package for evaluation of impulse voltage
parameters was developed. The development work was part
of MIKES’s contribution to revision of IEC standards 60060­1 and
61083­2. The software implements calculation of test voltage value
and related time parameters using curve fitting and digital filtering techniques as described in the new standard revisions.
PQED Photodiode
Is your laboratory vibration sensitive?
The iMERA+ qu-candela project of the European Metrology Research Programme developed the Predictable Quantum Efficient
Detector (PQED) that was demonstrated to be a very useful semiconductor device for absolute optical power measurements at
room temperature. A new compact room temperature PQED has
been designed and constructed in collaboration with Fitecom Oy.
The PQED may replace the sophisticated cryogenic radiometer, operated close to the temperature of 4 K, as a primary standard of
optical power giving the benefits of room temperature operation
and ease of use similar to conventional trap detectors.
Vibration conditions and effects are monitored in MIKES laboratories 24/7. The system consist of two seismic 3D acceleration
transducer combinations. This system can be used to monitor how
different solutions for vibration control are working. MIKES is offering vibration measurements for customers in different kind of
situations: e.g. results from vibration measurements can be a helpful tool when designing and building laboratories and other buildings as well as monitoring external effects caused by traffic and
construction sites.
Interested? Please contact our Customer Service Manager
Veli-Pekka Esala, Veli-Pekka.Esala@mikes.fi
MIKES METROLOGY TOP 5
19
ARCTIC METROLOGY
Text: Petri Koponen
Photos: MIKES archives
Staff of MIKES-Kajaani (from left): Sauli Kilponen, Petri Koponen, Kari Kyllönen, Jani Korhonen, Timo Nissilä and Aimo
Pusa. Second from right Dr. Rainer Engel from PTB Germany.
MIKES-Kajaani, the world’s northernmost national
standards laboratory located near the Arctic Circle,
has integrated well to the local research community,
and serves both national and international customers with calibrations and special services. Premises in
the newly designed, renovated building have proper
temperature, vibration and humidity control as well
as precisely determined g-values. The group running
the facility is built up from seven local experts. Force,
torque and heavy masses are in full service and serve
industry in its calibration needs. The assembled three
different water flow calibration rigs are under development.
MIKES is a partner in a joint research centre CEMIS (Centre for
Measurement and Information Systems; the umbrella organisation
of measurement technology in Kajaani) together with the Universities of Oulu and Jyväskylä, Kajaani University of Applied Sciences,
and VTT (Technical Research Centre of Finland). CEMIS specialises in
research and training in the field of measurement and information
systems. In this cooperation, MIKES has been active in applied research varying from optical emission based measurement methods
of heavy metals in water to ski base topography measurements.
New thinking of reliable measurement results is implemented in
every project. MIKES-Kajaani will also take part in an EMRP-project
concerning the development of big force measurements.
20
MIKES METROLOGY TOP 5
Unit
Range
Relative
uncertainty (k=2)
1 N – 1.1 MN
2·10-5 – 1·10-4
8 devices
Torque
0.1 Nm – 20 kNm
2·10-4 – 5·10-4
7 devices
Mass
50 kg – 2000 kg
2·10-6
3 devices
Water flow
0.2 l/s – 750 l/s
0.03 % – 0.5%
Consistency
0 – 12 %
0.2 %
Force
Remarks
Gravimetric or
Reference
flow rate 0.5 m/s – 4.0 m/s
(dependent of the consistency)
Gravimetric primary standard for
liquid flow calibration
The gravimetric reference standard of water flow is based on
weighing the water. The flow diverter is an essential part of the
test rig. It diverts the water flow into the weighing system and
switches it back to the storage tank at the end of the measurement. It is responsible for measurement timing control and the
shape of the water flow profile when the flow is entering and
leaving the balance.
In the measurements, water is first continuously pumped up to a
constant head tank located 20 m above ground level. The water
level is held constant in the tank by sufficient overflow and
by adjusting the water flow in a measuring pipe section, where the
flow meters under test are placed. When the desired water flow
rate is achieved and stabilised, the water flow, Q, is diverted into
the weighing tank. Measuring starts (t1) and the output of the
meter under test is registered. When a specified time has elapsed
(tm), the water flow is diverted to pass by the diverter and the
measurement is stopped (t2).
Height 20 m
MIKES-Kajaani is developing methods for traceable liquid flow
calibrations. Traceability with big water flow measurements (DN
200 – DN 500, i.e. for pipe diameters from 20 cm to 50 cm) are
based on reference meters and with smaller flows (DN 10 – DN 200)
to gravimetric measuring principle. The gravimetric measurement
system consists of two diverter- weighing systems with a 800-kg
and 6000-kg balance (only one of these is visible in the illustration). Measurements carried out using this calibration rig are traceable to the national standards of mass and time. This gravimetric
primary standard will serve as the national standard for flow and
it will be used to calibrate all types of flow meters sizing DN10, DN
50, DN 100 and DN200. The targeted measurement uncertainty is
0.03 %.
The schematic picture shows the flow rate which is directed into the weigh
tank as a function of time. After the diverter is actuated, the flow rate into
the weigh tank increases up to the value Q. The characteristic of this rise
depends mainly on the characteristic of the speed of the diverting edge, the
shape of the jet’s cross section and the velocity profiles across the jet width.
The red areas should be equal to the green areas.
Measuring pipe
Diverter
Q
Pipe to
bypass
Overflow pipe
Weighing system
Volume 14 m3
Feed pipe
MIKES METROLOGY TOP 5
21
THE MIKES BUILDING
THE HOME OF HIGH-PRECISION METROLOGY
Building maintenance technology
with a focus on airconditioning
About 30 % of the total building area is devoted to
building maintenance technology, mainly ventilation
equipment, required for creating laboratory conditions.
Potential sources of electromagnetic interference, such
as compressors and the emergency power generator, are
located as far away from the laboratories as possible.
There are 36 laboratories that are divided in 20 sections,
each of which has its own dedicated ventilation system
used for the fine tuning of temperature.
Expansion joints and double walls
The propagation of internal vibrations caused by building maintenance technology and the movement of
people has been inhibited by dividing the building into
several separate sections using expansion joints. In the
surface laboratories, the basic idea is an onion-like structure, in which the laboratories at the core are protected
from external temperature variations by a corridor, an
office room and outer protective shutters. To optimise vibration performance, the walls, floor and ceiling of each
laboratory are joined together by steel rods and poured
concrete in such a way that each laboratory behaves as
a rigid body.
Stable temperature
Instruments requiring high temperature stability are
mounted in enclosed equipment cabinets supplied with air
whose temperature is regulated to an accuracy of ±0.01
degrees, or liquid baths that can achieve accuracies of a
few millidegrees. For vibration-sensitive equipment, the
laboratories use granite tables with natural rubber isolators.
Vibration isolation
Extremely vibration-sensitive length and mass metrology equipment is mounted on either air-spring supported
80–120 ton concrete slabs of gravel/insulation carpeting/
solid slab structures. These provide attenuation of bedrock
vibrations at 1 Hz and higher frequencies. The building is
founded on a competent bedrock.
Isolation of heat sources
Because of the strict room temperature requirements,
the air heated by, for example laboratory light fixtures
and hot furnaces, is drawn directly away from the laboratory and returned into circulation. The temperature,
humidity and pressure of the air in laboratory facilities,
as well as the mechanical vibrations between floors are
constantly monitored.
Technical specifications
•
•
•
•
•
•
•
Building volume: 51 000 m3
Total building area: 9 100 m2
Net floor area 6 500 m2
Number of employees: 80
Number of offices: 60
Number of laboratories: 36
Total laboratory floor area: 1 700 m2, out of which
670 m2 is underground
2
MIKES building from inside
Recent publication
A. Lassila, M. Kari, H. Koivula, U. Koivula, J. Kortström, E. Leinonen, J. Manninen, J. Manssila, T. Mansten, T.
Meriläinen, J. Muttilainen, J. Nissilä, R. Nyblom, K. Riski, J. Sarilo, and H. Isotalo. Design and performance of an
advanced metrology building for MIKES. Measurement 44 (2011) 399-425.
22
MIKES METROLOGY TOP 5
20 kV
T1
Electrical interference and electromagnetically shielded laboratories
Steel reinforcements within the concrete frame of the
building are welded together at 1.2 m intervals to provide
a continous mesh. This type of a “Faraday Cage” protects
the laboratories from external electrical interference up
to the radio frequency range (fcut-off~200 MHz). The thick
concrete walls and the underground placement of the laboratories also reduce interference. For extremely sensitive
electrical measurements, the building has 12 electromagnetically shielded “rooms”. For external fields, their minimum shielding attenuation is 100 dB (10 kHz to 20 GHz). In
order to minimise power supply interference, these rooms
are equipped with optical fibre lighting and symmetrical
filtered power supplies (2 x 115 V). See Figure 1.
800 kW
MDB1
MDB2
IT
IT
FILTER
FILTER
LAB 1
...
T2
800 kW
LAB 13
LAB 12
FILTER
FILTER
IT
IT
...
LAB 36
HVAC1
HVAC2 ... HVAC41
= Screened room laboratory
= Normal laboratory
= noisy load e.g. air conditioning
machine
UPS
2x60 kW
UPS
T
MDB
IT
USP
EPG
= 20 kV/400 V transformer
= Main distribution board
= Isolation transformer
= Uninterrupted power supply
=Emergency power generator
2x60 kW
Figure 1. The principle of electrical power distribution.
Ventilation and diffusion
technology
The laboratories with the strictest temperature
stability requirements have been constructed in
naturally constant temperature underground
floors based on the “room within a room” principle. The actual measurement room is placed
within a slightly larger room so that the air
drawn from the measurement space air washes
the intermediate space as it is returned into circulation. This solution enables the maintenance
of a set temperature of 20 °C to an accuracy of
0.01 degrees. Most of the laboratories are constructed using the floor diffusion principle, with
the exeption of mass metrology laboratories,
which require cleaner conditions, where ceiling
diffusion is used, and the humidity laboratory,
where wall diffusion is used. A room where the
temperature can be set at (20±5) °C makes studies of the temperature dependence of devices
and meters possible.
Atomic clocks
The atomic clocks are continuously compared
against UTC using a GPS satellite receiver. An
antenna tower provides optimum satellite visibility in the southern sky.
Drawing: Minna Kuusela
MIKES METROLOGY TOP 5
23
MIKES
Mittatekniikan keskus
CENTRE FOR METROLOGY AND ACCREDITATION
TEKNIIKANTIE 1
FI-02150 ESPOO
FINLAND
MIKES-KAJAANI
TEHDASKATU 15
PURISTAMO 9P19
FI-87100 KAJAANI
FINLAND
www.mikes.fi
MIKES METROLOGY TOP 5