THE 2nd YEAR LABORATORY
THE SPECTROSCOPY
EXPERIMENT
THE SCRIPT
AND
SAFETY INSTRUCTIONS
Revised: 5th October, 2015.
Version2.0
1
You must sign the sheets provided in the lab to confirm that you have read and
understood the safety instructions given here and on pages 19 and 20 of this lab
script before starting any experimental work. If anything is unclear please ask your
demonstrators.
You are encouraged to ask your demonstrator not only for assistance in any experimental
difficulty, but also for discussion about any points of procedure and background physics
that may arise.
2
Preliminary Tasks: to be completed before this lab.
1. In your lab book draw a diagram of the sun, indicating the following regions; corona,
chromosphere, photosphere (quiet sun-centre), prominence, flares and sunspots.
2. The relative population of two atomic population states in equilibrium is given by Boltzmann
Distribution:
where  is the energy difference between the two states, T is the temperature and  the Boltzmann
constant = (1.38 × 10 - 23 J K -1). For hydrogen the energy difference between the ground state and
the first excited state is 10.2 eV. In your lab book calculate the population of the first excited state
compared to the ground state for a temperature of T = 6000 K, and comment on this.
SECOND YEAR LABORATORY SPECTROSCOPY EXPERIMENTS
Introduction
Spectroscopy has probably been the single most important tool in the development of
modern physics, particularly in the historical development of ideas of atomic structure
leading to the development of quantum theory. In present day physics the technique of
spectroscopy remains of importance in the study of the structure of atoms and molecules,
and also has become a fundamental and powerful technique in many other fields such as
astronomy and plasma physics. The Second Year Laboratory spectroscopy experiments
are designed to introduce you to some fundamental ideas and also to give you experience
in making spectroscopic observations.
There are three parts to this spectroscopy laboratory: two practical experiments (A, B) plus
an analytical project (C) on astrophysical spectroscopy. Half the allocated time is spent on
the analytical project C, and the other half on one of the two practical experiments (A or B).
You will undertake:
EITHER
A: The Quantum Defect experiment, involving photographic recording of spectra. This
experiment is designed to allow you to obtain a permanent record of the spectra of mercury
and of lithium (an alkali metal), using a quartz prism spectrograph. The spectra you record,
and your analyses of these, are designed to deepen your understanding of atomic
structure.
OR
B: The Molecular Spectroscopy experiment uses not a spectrograph but a simple
monochromator combined with photo-electric detection for the study of the behaviour of a
rapidly pulsed light source, together with an investigation of the absorption and
fluorescence of solutions of organic dyes (which commonly form the basis of a type of
frequency tunable laser).
AND also:
C: The analytical spectroscopy project is based on a vacuum ultra-violet spectrum of the
Sun from Skylab. Analysis of this spectrum will give you experience in how an astronomer
would start to interpret a new spectrum of any astrophysical object, and by a straightforward but careful examination of the spectrum it is possible to deduce a great deal about
the conditions in different regions of the Sun.
3
A. Measurement of Quantum Defect values for Lithium
The aim of this experiment is to measure the quantum defects of the lithium atom. Lithium
is an alkali metal. The quantum defect is a measure of the difference between an energy
level and the corresponding one in hydrogen i.e. the extent to which an outer (valence)
electron of a given angular momentum penetrates the inner shell of the atom. To achieve
this you are required to record photographically the spectrum of lithium using a quartz prism
spectrograph. The spectrum you record and its analysis will deepen your understanding of
atomic structure.
1. EXPERIMENTAL PROCEDURE
The spectrograph contains a prism which provides spectral dispersion. The lithium
spectrum is recorded on a strip of 35mm film. You will also record a mercury spectrum,
and accurately known wavelengths of lines in the mercury spectrum will be used to
calibrate the wavelength scale. (The actual calibration varies as a result of the development
procedure - film shrinks when drying.) This calibration allows you to measure the lithium
line wavelengths that you will need for investigating quantum defects in lithium.
Before beginning, your demonstrator will explain the optics of the spectrograph to you. This
consists of an entrance slit, collimating lens, prism, focussing lens and film holder. The
optical components are made of quartz.
- Sketch a labelled diagram of the spectrograph.
Why is the plane of the film holder not normal to the exit axis of the instrument?
What would the effect be of changing the slit width and the length of the slit? (The slit width
has been preset and hence should not be altered, however the slit length is adjustable).
The internal optics of the spectrograph have been carefully set up; do not re-adjust.
After reading the precautions listed at the bottom of this page and overleaf, your aim
is to obtain, on one piece of film, the following:
(a)
(b)
(c)
the mercury spectrum using the lamp provided, and an exposure time of about 30
seconds.
the carbon arc spectrum, for which clean electrodes must be used: expose for
about 15 seconds.
the lithium spectrum which is obtained by “doping” i.e. placing a small amount of
lithium chloride on the lower electrode of the arc. Again use 15 seconds exposure.
For the purpose of line identification it is recommended that two adjacent spectra are taken
by adjusting the position of the film holder. At the first position the pure carbon spectrum (b)
should be recorded, and then at the second position, record both the spectrum of mercury
(a) and lithium spectrum (c). The length of the slit should be reduced for the mercury
spectrum so that the mercury lines can be easily distinguished, and you will use these
mercury lines for wavelength calibration of your film.
Practical details: in practice, the correct exposure times have to be found experimentally
since they depend on the alignment, the amount of lithium used, and the stability of the arc.
Photographic film is a logarithmic recording medium - successive doubling of the exposure
time causes equal increments in the blackening of the spectral lines on the film. Think
about what this means, and what it implies for how you might adjust exposure times.
It may be necessary to take several spectra using different exposure times in order to
properly expose both the weak and strong features.
READ THE PRECAUTIONS OVERLEAF BEFORE STARTING EXPERIMENTAL WORK.
4
PRECAUTIONS
THE DC SUPPLY MUST BE DISCONNECTED WHEN THE ARC IS NOT IN USE
Do not expose your eyes unnecessarily to either the arc or mercury lamp since they
are strong emitters of UV. This can cause “sunburn” of the whites leading to severe
pain some hours later. This phenomenon, known as arc-eye, is only temporary but
still very unpleasant. Goggles are provided for your protection – use them.
Disposable gloves should be worn when carbon electrodes are handled. This avoids
contamination of electrodes with NaCl from perspiration.
Lithium Chloride is corrosive – if you get any on your skin or clothes, wash off
immediately with a plentiful supply of water.
Keep belongings well away from the experimental equipment as this gets very hot.
Keep the clean carbon electrodes separate to those that have been in contact with
lithium chloride – separate labelled handling trays and tools have been provided.
At the end of each block of two days in the lab, return the carbon rods to the correct
tray, either clean or lithium contaminated, so there is no confusion for the next
students due in lab.
Answer this safety question in your lab book BEFORE recording your spectra: why
must you wear safety goggles during this experimental work? Once you have answered
this you may go ahead and record your spectra.
2. MEASUREMENT OF THE LITHIUM LINE WAVELENGTHS
Once you have developed the film, the positions of the mercury and lithium lines in the
spectra are measured using a travelling microscope. The known mercury line wavelengths
to be used as wavelength standards are provided in the lab.
Make a wavelength calibration curve by plotting the mercury line positions (x-axis)
measured on the film against the mercury line wavelengths (y-axis). The calibration curve
can be drawn by hand or by using a polynomial fitting routine. Now use the measured
lithium line positions in conjunction with the calibration curve to determine the lithium line
wavelengths and their uncertainties. You will need to consider all sources of uncertainty in
the lithium line wavelengths you have measured.
3. ANALYSIS
Your aim is to use the lithium wavelengths you have measured, and their uncertainties, to
find values of quantum defect for some energy levels in lithium.
Background: Photons are emitted with a frequency corresponding to the energy difference
between the upper and lower levels involved in the electron transition. In the case of
hydrogen the energy levels are given by:
E
 hcR
n2
[1]
and the energy difference between levels n1 and n2 is given by:
1
1
 hcR  2  2 
[2]

 n1 n2 
where n is the principal quantum number, R is the Rydberg constant and ΔE is the energy
E 
hc
of the photon.
5
For many-electron atoms, the theoretical situation is more complex and even with modern
computers cannot be solved exactly to find the energy level values. This is because the
interactions of the valence electrons with those electrons of the inner shells may be as
strong as the interactions between the valence electrons and the nucleus.
However, in the alkali metals such as lithium, with one valence electron, the single outer
electron moves in the field of the nucleus and the spherically symmetric charge distribution
due to the inner closed shell electrons. The potential remains central but no longer
Coulombic. In this case a formula similar to that for hydrogen may be used:
E 


1
1
 hcR 


2

n2  A2 2 
 n1  A1 
hc
[3]
where A1 and A2 are called quantum defects, and are a measure of the difference between
a particular energy level and the corresponding one in hydrogen (see Figure 1) i.e. the
extent to which an outer (valence) electron of a given angular momentum penetrates the
inner shells of the atom.
The magnitude of the quantum defect depends on the angular momentum quantum number
l of the state, consider why this should be?
Hint: see definition of quantum defect given at the beginning of section A. Please discuss
with your demonstrator.
(Also, you may find the text books listed overleaf useful, and there is also a poster on the
board in the lab with useful information.)
Familiarise yourself with the energy level diagram and lithium transitions shown in Figure 1.
In the visible and near ultraviolet the lithium spectrum consists mainly of three series of
lines, called the Principal, Diffuse, and Sharp series.
For the Principal and Diffuse series of lines, by assuming A2 << n2 , a plot of λ-1 against
(n2)-2 should yield a straight line whose intercept should enable A1, the quantum defect for
the lower level of the series, to be determined.
For example: for the Principal series (in which the lower level of a transition has a 2s
valence electron and the upper level has in each case a n p p valence electron), we have:


1
1
 R

2
2





2

A
n

A
S2
P
Pnp


1
[4]
Where:
AS2 is the quantum defect of the 2s 2S level, APnp is the quantum defect of level np p 2P,
np is the principal quantum number of the P terms, and
R is the Rydberg Constant = 10.97×10-3 nm-1 .
6
As already indicated
APnp << AS2 and so APnp can be ignored.
Thus, we have:

1
1
R
R
 R




2

n P2  2  AS 2 2 n P2
 2  AS 2 
1
[5]
So if we plot λ-1 against (nP)-2 we should obtain a straight line whose intercept, CS2, should
allow the value of AS2 to be found:
i.e. C S 2 
R
2  AS 2 2
 AS 2  2  R CS 2
[6]
Find the value of AS2 for the principal series using the above method. Remember to
estimate the error in the value you find. You are reminded that the demonstrators are
there to help you, so please discuss your analysis with a demonstrator.
Repeat the above procedure for the Diffuse series to determine AP2 and its error.
Now, consider your values for quantum defects AS2 and A P2. You have already
considered possible reasons for a trend in quantum defect with angular momentum
quantum number l.
What trend in quantum defect do you observe as the angular momentum quantum number
increases? Explain why this should be (discuss this thoroughly in your lab book, including
diagrams where helpful. Discuss with your demonstrator.).
If there is time you can also consider the Sharp series, and this requires a bit more thought.
Some useful text books for finding out more about Quantum Defects:
“Atomic Physics”, C. J. Foot, Oxford Master Series in Physics, OUP, 2007
“Atomic Spectra”, H.G.Kuhn, Longmans, 1964
“Elementary Atomic Structure”, G.K.Woodgate, Oxford Science Publications, OUP, 2002
You are reminded that all measured data should be given in tables in your lab
book even if you are using software to plot graphs.
7
Figure 1.
Sharp
series
Diffuse
series
Principal
series
Note: Wavelengths on the diagram are in units of Ångstroms, (1 nm = 10 Å ) and are approximate
only.
8
B. Measurement of Molecular Absorption and Fluorescence for
an Organic Dye Molecule (Pulsed spectroscopy experiment).
The aim of this experiment is to measure absorption and fluorescence in the organic dye
molecule, Fluorescein (Organic dyes form the basis of one of the most widely used types of
tunable lasers).
You will learn how to investigate the absorption of light by a material and how that can be
used to investigate the properties of the material. This includes learning how to obtain
physically-useful spectra. You will also learn about some of the processes whereby
molecules absorb and emit radiation.
The experiment uses a monochromator (rather than a spectrograph) to analyse the spectral
behaviour of the light being examined. A xenon gas light source is used, providing a broad
band light source for the absorption and fluorescence measurements. The xenon lamp is
pulsed in order to provide a sufficiently intense light to generate detectable fluorescence
from the organic dye sample without using a huge amount of power. The light passes
through the monochromator and is then detected using a photomultiplier tube detector
system. The output current of the photomultiplier tube detector is conveyed via a co-axial
cable to a termination resistor box. The value of the terminating resistance may be chosen
to optimise the signal. The voltage developed across it is displayed on the oscilloscope.
In the experiment you will:
(i)
(ii)
(iii)
(iv)
(v)
check the wavelength calibration of the monochromator
obtain the spectrum of the xenon lamp.
obtain the absorption spectrum of Fluorescein dye
obtain the fluorescence spectrum of the dye
place the xenon spectrum on a physically useful flux scale by comparison with a white
tungsten bulb spectrum.
You are reminded that all measured data should be given in tables in your lab book
even if you are using software to plot graphs.
Details of the photomultiplier tube detector system
The gain of the photomultiplier is controlled by the applied high voltage which must not
exceed l kV. It is usually adequate to operate with 500V. The output voltage pulse is
developed across the variable terminating resistor, R. Set the resistor so that the pulsed
(or DC) output voltage is much less than the voltage across the last stage (dynode) of the
photomultiplier. This is important to prevent non-linear behaviour. If the output voltage
pulse is too high it could reduce significantly the voltage across the last stage leading to an
underestimate of the light intensity. For an applied voltage of 500V, the voltage across the
last stage is 55V. Thus, the pulsed (or DC) output voltage should not exceed 1 or 2 volts.
The voltage pulse is displayed on the oscilloscope and also used to trigger it; a time-base
speed 10µs/cm is convenient. The oscilloscope should be operated in triggered mode
because the repetition period of the lamp is very long compared to the duration of the
pulse.
NOTE: Measuring circuits have response times; it is usually important to know them, and
control them. The anode of the photomultiplier is a current source of very high impedance.
The terminating resistance, R, together with the cable capacity (l00pF/m) and the input
capacity of the oscilloscope (40pF) form a differentiating time constant.
Examine the effect of this time constant by observing the variation of the height, rise-time
and duration of the pulse as R is varied.
9
MEASUREMENT (i) use the known Mercury line wavelengths to check the
monochromator wavelength calibration.
The transmission wavelength of the monochromator is set by a knob calibrated in
nanometers nm. The calibration should be checked using the mercury light source
provided. This operates at mains frequency. Wavelengths of the brightest mercury lines
are:
Violet: 435.8 nm,
Green: 546.1 nm,
Yellow 1: 577.0 nm,
Yellow 2: 579.1 nm
How accurate is the calibration?
MEASUREMENT (ii) obtain the spectrum of the Xenon lamp
Using the pulsed xenon lamp as the source (see NOTE below), quickly scan the
monochromator across the range 330nm – 650nm and observe the variation of the pulse
amplitude. Note the effect of the fine line structure.
In the measurements you are about to make, you should reduce the measurement
wavelength interval size around the fine line structure, and increase it where the spectrum
changes slowly with wavelength.
Now slowly scan the monochromator across the range 330nm – 650nm and record the
pulse amplitude at each wavelength position. An average interval size of 5nm is about right.
You must not vary the geometrical arrangement during a scan.
NOTE – measurement (iii) will use the exactly the same experimental arrangement, except
that a cell containing dye will be placed in the Xenon light beam, make sure you allow
space for this in your set-up for (ii).
Plot the resulting spectrum.
Keep the same experimental setup for measurement (iii)
MEASUREMENT (iii) obtain the absorption spectrum of Fluorescein dye
Repeat measurement (ii) but with a cell containing the Fluorescein dye solution placed in
the beam (using the transparent cell walls). The dye is Fluorescein and contact with the
skin should be avoided. In case of accident wash very thoroughly. Use the 5mg/L
concentration for this part of the experiment in order to avoid severe saturation. You will
see that the dye absorbs by varying amounts across the spectrum.
You should consider reducing your measurement intervals in the region where the
dye produces marked differences from measurement (ii).
The resulting measured transmission spectrum should be divided (i.e. normalised) by the
values obtained in measurement (ii) in order remove the effects of (a) the xenon light
spectrum and (b) the spectral response of the apparatus.
Plot this normalised
transmission spectrum. Also plot the normalised absorption spectrum.
Using Appendix A, plot optical depth versus wavelength for the normalised dye absorption
spectrum. From this, calculate the peak absorption cross section for the dye given that the
cell is of length 10mm and the dye is of molecular weight 376.
Also compare your normalised transmission spectrum with that shown in Figure 2, which
was taken with a higher dye concentration, and comment on any differences.
10
MEASUREMENT (iv) obtain the fluorescence spectrum of the dye
Place the monochromator/photomultiplier assembly at right angles to the incident beam so
as to observe the light re-emitted at 90o. Use the 20mg/L concentration dye sample for this
part of the experiment. (Why?)
Find the wavelength region where the fluorescence emission occurs and plot the spectrum
in that region. The fluorescent light intensity is small, and so a larger gain may be used.
Also, care should be taken to exclude stray light.
Ask your demonstrator to explain to you why the absorption and fluorescence wavelengths
differ. (Your demonstrator may also explain how this is used in a dye laser, or you can
investigate this for yourselves.)
MEASUREMENT (v) place the xenon spectrum on a physically useful flux scale by
comparison with a white tungsten bulb spectrum.
When you record a spectrum, you usually want the y-axis to be in a useful unit such as flux
(watts/m2/nm). However, the instrument has a response to the input light intensity which
varies with wavelength. One reason is that the photomultiplier really measures the photon
count rate, rather than the flux. In this final section, you are asked to convert the y-axis of
the xenon spectrum obtained in part (ii) so that it is proportional to the input flux.
Instead of the xenon lamp, use the tungsten bulb as the source. In the visible region the
spectrum of the light emitted by the tungsten lamp approximates to that of a blackbody at
2000 K with intensity I(λ) given by:
1
1
 hc  
I    5  exp 
  1 .
   kT  
Verify that exp(hc/λkT)>>1.
Thus, the simpler Wien approximation may be used:
I   
1
5
exp  hc kT 
Calculate I(λ) for some ten values of λ spaced over the full range and, with the tungsten
lamp as source, measure Iobs (λ) for those same wavelengths. Remember that the lamp is
on continuously so the oscilloscope must be D.C. coupled.
Using your results, calculate and plot the system response function, R(λ):
R  
I obs  
.
I  
Now re-plot the results of measurement (ii), the spectrum of the xenon lamp, after dividing
them by R(λ) to give a more physically useful spectrum of the xenon lamp.
Similarly, if you have time, also re-plot your results for (iv), the fluorescence spectrum of the
Fluorescein dye molecule.
11
Figure 2.
12
Appendix A
If monochromatic light of initial intensity I0 passes through an absorbing medium of length l
then the emergent intensity is given by:
I(l) = I0 exp(-τ)
where τ is the OPTICAL DEPTH (see Thorne: Spectrophysics, p. 291).
For a homogeneous medium the optical depth is given by:
l
   N dl  N l
0
where N = number of absorbing species/unit volume and σ = absorption cross section.
Hence, measuring I(l)/I0 and knowing l and the concentration gives σ.
(Note: Some books may use the absorption coefficient k where k = N σ ,
i.e. τ = kl.)
13
C. Analysis of the Solar UV Spectrum
The aim of this study is to: identify the origin of spectral features in the Solar ultraviolet (UV)
spectrum, and to use Solar UV spectra to investigate the conditions above the Solar
photosphere. The project is based on UV spectra of the Sun taken from Skylab. Skylab
was America's first experimental space station. Analysis of the spectra parallels very
closely the first stages that an astronomer would have to undertake in considering a new
spectrum of any astrophysical object. By a straightforward but careful examination of the
Solar spectra you will find that it is possible to deduce much about conditions in different
regions of the Sun.
You are reminded that all measured data should be given in tables in your lab book
even if you are using software to plot graphs.
A copy of Skylab spectra of the Sun is attached to your lab script (Figure 3). Please attach
this Skylab sheet in your lab book once you have completed this experiment,
The spectra are of three different regions above the solar photosphere:
(a) a Solar Prominence (a kind of outburst) – upper spectrum
(b) the quiet Sun centre (i.e.looking towards the middle of the Solar disk)– middle spectrum
(c) the Corona (the Sun’s outer atmosphere) – lower spectrum.
(In your preparatory work for this session you should already have a sketch of the sun in
your lab book. Check you have labelled Photosphere, Corona, and Prominence.)
It is possible to obtain a great deal of information by considering the strongest features in
these three spectra. Some strong features are marked on the spectra.
(1) Identify the element(s) responsible for the strongest lines marked α, β, γ, δ. Proceed
by measuring the wavelengths and intensities (and their uncertainties) of the four lines
(note that the intensity scale is logarithmic, and the wavelength scale is in
angstroms, 1 nm = 10 Å ) .
Compare your measurements with the values given for some elements in the data book
supplied.
DO NOT REMOVE THE DATA BOOK FROM THE LAB.
If you think you have identified an element in the spectrum, check that other lines predicted
for that element by the data book are also present at about the correct wavelength and
intensity. If they are not present what does this imply? Discuss with your demonstrator.
What elements do you consider are responsible for the features α, β, γ, δ, and why?
Comment on the relative number of lines observed from the main identified elements
If you have more than one possible element identification for a particular line/s how might
you estimate the relative contribution to the line feature from each element? What might
you learn from this about the chemical composition of the sun?
14
(2)
Explain the origin of the two prominent regions of continuous, as opposed to line,
radiation and their relationships to any other relevant features in the spectrum. Begin by
measuring the peak wavelength of the continua and then convert to units of eV. Does this
give you any clues? (you may wish to consult the lab databook).
Discuss with your demonstrator.
(3) Use your measured wavelengths and intensities of the α, β, γ, δ lines to obtain
estimates of the temperatures near the solar surface (quiet Sun centre) and in the
prominence. Begin by assuming that the hot gas is in thermodynamic equilibrium. For this
situation, the line intensity i.e. the rate of photon production, R, depends on two things – the
population, N2, of the upper level of the emitting atoms, and the Einstein probability
coefficient, A21, for the transition:
R  N 2 A21  N1 A21 exp  E k BT 
What is ΔE?
How might you use this expression to determine the temperature T? Check with your
demonstrator before you proceed. (Also see detailed guidance on this in the data books
provided.)
Hence find the temperatures of the quiet sun centre and the prominence using your results
from (1) for features α, β, γ, δ. (Values for the Einstein probability coefficients, A21 , are
given on the board in the lab).
Consider all possible sources of error and how they affect your calculation of temperature.
You may find that use of the above expression fails to give a useable result. If so, can you
think why?
Read the notes given in the databooks provided, and discuss with your demonstrator how
you might modify your approach to finding the temperature of the quiet sun centre and
prominence.
Use your modified approach clearly stating your assumptions, to find a further estimate of
the temperatures of the quiet sun centre and the prominence region.
How do these
temperatures compare with one another?
Note: as part of this task you will need to find the gradient of a plotted line. For the first of
your plots using your modified approach, please find the gradient as follows:
Use OriginPro (or Python) software to find the best fit line to your data points
and the gradient. You will need to also find the error in the gradient, and a value that
describes the quality of the line fit.
You should now have estimates of the temperature, with associated errors, for both the
quiet sun centre and the prominence region. Discuss in your lab book how these
temperatures compare with one another.
15
(4) Use the intensity distributions in the continuum regions to plot graphs from which you
can derive further estimates of the temperatures in the solar surface (quite sun centre) and
prominence, and associated errors.
How do these compare with the temperatures obtained in part (3)? If the temperatures
differ, why might this be the case?
Discuss with your demonstrator.
(5) What can you conclude about the temperature in the corona from the feature marked
Mg X?
(Give your reasoning in full).
(Spectra from ionized species are identified by a Roman number. Mg I = neutral
magnesium. Mg II = Mg+, Mg III = Mg++, etc.). You may use the lab data book provided
which gives ionization potentials for some ions of Mg.
Why is the feature, marked Mg X, seen in all three spectra?
(6) Explain, making notes in your lab book and consulting library books or otherwise
where relevant, the main differences between those parts of the spectra that can be
attributed to the solar surface, the prominence and the corona. Make sure to bring into this
what you have learnt about these regions during this project.
16
Figure 3.
17
Intentionally Blank
18
RISK ASSESSMENT AND STANDARD OPERATING PROCEDURE
1. PERSON CARRYING OUT ASSESSMENT
Name
Subhanjoy Mohanty Position
Staff
Date
05/10/1555
2. DESCRIPTION OF ACTIVITY (include storage, transport and disposal if relevant)
Spectroscopy Experiments in 2nd year Undergraduate Teaching Laboratory
3. LOCATION
Campus
Building
SK
Room
Blackett
415a
4. HAZARD SUMMARY
Accessibility
x
Mechanical
Manual Handling
x
Hazardous Substances
Electrical
x
Noise
Working at height
Extreme temperature
Falling objects
Pressure/steam
Trip hazards
x
Lone Working Permitted?
Yes
No
Developer and Fixer
Other
x
Permit-to-Work required for
planned maintenance?
Yes
No
N/A
5. Who might be harmed and how?
Staff / students
May be harmed if the
safety precautions
below are not
followed: risk of
electrical shock,
trip, burn, and
irritation to eyes
and throat.
Support staff
Cleaners, engineers etc
Other
6. How often is the process being carried out?
Once a day
Once a week
Once a month
Every 6 months
Annually
Other – give details: These are ongoing experiments undertaken by supervised groups of students during term
time. Equipment is used daily during term time.
7. Brief description of the procedure
Existing precautions (Controls)
Is risk high,
medium or low?
Accessibility
All bags, coats, jumpers etc to be placed
away from aisles and walkways.
M
19
Electrical
No adjustment of electrical, mechanical or
other parts by anyone other than designated
technicians, Mr Axtell or Mr Beaumont.
L
Hazardous Substances
Developer and Fixer are irritants, and must
not be swallowed. Do not get into eyes, wear
gloves, coats and goggles. Ensure good
ventilation when processing film.
L
Protection: Goggles, Gloves, Gown when
handling Lithium. Wash hands after. Avoid
ingestion and skin adsorption of Lithium.
Chemical [Corrosive]
Other
UV HAZARD Supplied protective goggles to
be worn in the presence of Arc equipment.
View arcs through green filter only.
BURN HAZARD
Carbon Rods to ‘red heat’ utmost care when
handling – ensure cool
H
M
H
ABSOLUTELY NO food or drink to be consumed
in Room 415a
8. Are extra precautions needed? If no please tick box and move onto next section
If yes, please describe
Who has been asked to do this?
By what date?
9. EMERGENCY ACTIONS
In the event of any accident with Lithium wash affected part{s} and send for technical staff.
All present must be aware of the available escape routes and follow instructions in the event of an evacuation.
10. Monitor and review
Controls should be monitored: daily
twice weekly
weekly
monthly
I will review this risk assessment at least every 6 months
6 monthly
annually
other
every 12 months
Immediately in the event of process / location change or incident or accident
11. Training record – use this section to record the names and date of any persons you are training in
this risk assessment and associated procedures
Name
Date
Name
Date
Note: http://www3.imperial.ac.uk/safety/formsandchecklists/raforms1 for specific risk assessment forms and
guidance http://www3.imperial.ac.uk/safety/guidanceandadvice on gases, biological agents, chemicals,
offsite work etc
20
STUDENT: Please complete boxes marked with asterisk*,
then affix firmly in lab notebook prior to handing in for Assessment
*NAME
*GROUP
*EXPERIMENT
HAND LAB BOOK IN NO LATER THAN 14:00
NOT
LATE
ASSESSOR
MARK ____/20
HEAD OF EXPERIMENT
DATE ___/___/20__
WORK IN LAB
[GRADE:
]
SUMMARY
[GRADE:
]
INTERVIEW
[GRADE:
]
FEEDBACK
21