Nuclear Science Experiments for Teaching Laboratories
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Nuclear Science
Experiments for Teaching
Laboratories
NUCLEAR MEASUREMENT SOLUTIONS FOR SAFETY, SECURITY & THE ENVIRONMENT
10 8
107
10 6
CE-138
CO-57
HG-203
SN-113
10 5
CS-137
Y-88
CO-60
CO-60
Y-88
Counts
10 4
10 3
10 2
101
10 0
0 500 1000 1500 2000
Energy (keV)
WWW.CANBERRA.COM
Nuclear Science Experiments with Digital Electronics
Laboratory Manual
Turn-key Training Solutions
Nuclear Science Experiments for
Teaching Laboratories
With a half century of experience in the nuclear measurements
industry, CANBERRA is uniquely qualified to provide educational
institutions with the tools for highly productive hands-on training
in the fundamentals of nuclear physics through vocationally-
relevant experiments.
CANBERRA offers turn-key solutions to set up and/or refurbish physics
teaching facilities with cutting-edge digital technology. A relatively
modest investment yields a flexible equipment configuration that can
serve undergraduate and post-graduate university training in addition to
in-house training for industrial users.
Experiment 8: Gamma-Ray Efficiency
Calibration (shown below) demonstrates
the procedure for measuring the efficiency
of a NaI and a HPGe detector as a function
of gamma-ray energy.
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Nuclear Science Experiments with Digital Electronics
Laboratory Manual
CANBERRA Lab Kits
CANBERRA has packaged a set of 12 experiments, focusing on various aspects
of gamma-ray detection and analysis, which provides an understanding of
basic principles to more complex nuclear physics applications.
ProSpect®:
Gamma Spectroscopy Software
OSPREY™: Universal
Digital MCA Tube
Base for Scintillation
Spectrometry
All of these experiments can be executed with CANBERRA
instrumentation and specialized ancillary equipment offered in
Lynx®: Digital signal analyzer
two Lab Kits. (Please note that most of the recommended radioactive
sources are not included and are readily available.) The Nuclear Science
Experiments with Digital Electronics Laboratory Manual provides a
step-by-step guide to performing the experiments. The Laboratory
Manual is available at www.canberra.com/labkit, and unlimited copies
may be printed as needed. OSPREY™
Lynx®
The experiments are built around CANBERRA’s Osprey™ and Lynx®
Digital Signal Analyzers. The versatility of these instruments enables
the performance of fundamental experiments in high and low resolution
gamma spectroscopy. Their advanced features allow for higher-level
experiments, such as coincidence and anti-coincidence, with both
hardware gating and event-by-event data collection.
The Osprey and Lynx are easy to use and feature highly-stable digital
electronics, thereby providing the optimum solution for laboratory
instruction. The devices are controlled with ProSpect™ Gamma
Spectroscopy Software which includes a flexible security feature to
ensure that the student is only presented with the functions required for
the class. This increases the productivity of the training.
Nuclear measurement solutions for safety, security & the environment. 3
Nuclear Science Experiments with Digital Electronics
Laboratory Teaching Solutions
The Laboratory Manual and kits greatly simplify the purchase
of equipment and implementation of these experiments
(plus other experiments of your own design).
They can be used to create individual student workstations or a central demonstration station,
depending on available space and budget. And, of course, lab expansion is just as simple as adding
more kits as needs dictate.
LABKIT-Basic LABKIT-Advanced
Supplement the starter
Starter kit for Experiments 1 to 5 kit to complete Experiments 6 to 12
>> Osprey Digital MCA >> LYNX MCA
>> ProSpect Gamma Spectroscopy Software >> BE2825 HPGe Detector System
>> 802 2x2 NaI Detector >> LabSOCS Software
>> LabKIT-Table: Apparatus for many of the >> 802-2x2 NaI Detector
experiments, including an angular scattering table
>> 2007P Preamplifier
and base plate, NaI 2"x2" detector shielding,
source collimation for LABKIT-SR-CS137, >> LABKIT-SRCEHLD: Set of Two HPGe Source
scattering pillar, and absorber holder. Holders, including a fixed source holder for
>> LabKIT-Abs: Sets of 4 generic absorber measurements at 25 cm and an adjustable source
materials, including aluminum, copper, lead, and holder for measurements from 0 to 18 cm.
polyethylene. >> LABKIT-NAICOLL: NaI 2" x 2" detector shielding
>> LabKIT-SR-Cs137: 15 MBq (0.5 mCi) Cs-137 for use with LABKIT-Table assembly.
source capsule, for use with the LABKIT-Table >> RCP-10-Cable: 10ft cable bundle including
assembly. preamp, SHV-SHV, and two BNC-BNC cables.
OSPREY™: ProSpect®: Gamma 802 2x2 NaI Shown: LabKIT-Table, LabKIT-Abs LabKIT-SR-Cs137
Universal Digital Spectroscopy Software Detector LABKIT-NAICOLL
MCA
Lynx®: Digital BE2825 HPGe LabSOCS 2007P LABKIT-SRCEHLD LABKIT-NAICOLL RCP-10-Cable
signal analyzer Detector System Software Preamplifier
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Nuclear Science Experiments with Digital Electronics
Laboratory Teaching Solutions
The Laboratory Manual presents the following
twelve experiments.
With LABKIT-Basic, students can perform experiments 1-5. To perform all
twelve experiments, LABKIT-Basic and LABKIT-Advanced are required.
Experiment 1 Experiment 6 Experiment 10
Gamma-Ray Detection Signal Processing Positron Annihilation
with Scintillators with Digital Signal By using coincidence counting
In this introduction to gamma-ray
Electronics techniques and the Angular
detection, students will identify Using the built-in Digital Signal Correlation table, students explore
photoelectric effect, Compton Oscilloscope feature of the LYNX the geometrical behavior of
scattering, and pair production in MCA, students observe the effects positron annihilation events.
a spectrum and perform an energy of changing signal processing
calibration using known reference parameters using several different Experiment 11
sources. acquisition modes.
Mathematical Efficiency
Calibration
Experiment 2 Experiment 7
Mathematical modeling is
Counting Statistics and High-Resolution increasingly used instead of source
Error Prediction Gamma-Ray based efficiency calibration for
Students will perform a series
Spectroscopy with improvement in cost, flexibility, and
of background and gamma-ray
HPGe Detectors safety. In this experiment, students
measurements with a NaI detector Semiconductor gamma-ray generate efficiency calibrations
and apply statistical principles to detection is introduced and using CANBERRA's LabSOCS
these measurements. students compare HPGe resolution efficiency calibration software and
to NaI detector resolution. compare against traditional source
based calibrations.
Experiment 3
Gamma-Ray Absorption Experiment 8
in Matter (Basic) Gamma-Ray Efficiency Experiment 12
Students will measure the effective
Calibration True Coincidence
attenuation of a set of materials Using both a NaI detector and an Summing
with varying densities and photon HPGe detector, the concept of Students observe true coincidence
absorption cross sections. detection efficiency is explored. summing and quantify the effect
on observed count rate using
Experiment 9 LabSOCS mathematical efficiency
Experiment 4 software.
Compton Scattering Gamma-Ray
Using the Compton Scattering
Coincidence Counting
table developed specially for this
Techniques
exercise, the principle of Compton Counting with multiple detectors
scattering and the dependence on correlated in time can yield
angular variation is demonstrated. incredible information about
fundamental nuclear structures.
In this experiment, students learn
Experiment 5 these techniques by acquiring
Half-Life Measurement and interpreting time-stamped
Students calculate the half-life of list mode data for synchronized
a short-lived nuclide using multi- detectors.
channel scaling acquisition.
Nuclear measurement solutions for safety, security & the environment. 5
Nuclear Science Experiments with Digital Electronics
Laboratory Teaching Solutions
As you can see in this sample, the format of each experiment
begins with the goal and the equipment required.
Each description includes the required steps together with the format of the data entry and
the results. In some cases, the instructor may wish to produce his or her own laboratory
script with this as a starting point.
s
ts with Digital Elect ronic
Nuclear Science Experimen
Laboratory Manual
Experiment 1
wi th
Gamma-Ray De tec tion
Scint illa tor De tec tors
Equipment Required:
Purpose:
ProSpect: ProSpect Gamma Spectroscopy Software
scintillator
1 To demonstrate the use of a NaI rs
a rays. Osprey Digital Tube Base MCA with connecto
detector and its response to gamm Osprey :
three domin ant gamma-ray 802-2x 2: NaI Detector 2" x 2"
2 To demonstrate the
ry Scattering Table Assembl y:
interactions with matter. LABKIT-Table : Teaching Laborato
tion. NaI Detector Shielding
3 To demonstrate energy calibra
137 Cs button source 1 microcurie, ± 20% unc
Radioisotope :
60 Co button source 1 microcurie, ± 20% unc
Radioisotope :
88 Y button source 1 microcurie, ± 20% unc
Radioisotope :
LEARN MORE
6
environment.
ns for safety, securit y & the
Nuclear measurement solutio
Please visit us at:
www.canberra.com/Labkit
for more information
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Nuclear Science Experiments with Digital Electronics
Laboratory Teaching Solutions
Experiment 1 Experiment 1
1 Gamma-Ray Detection with Gamma-Ray Detection with 1
Scintillator Detectors Scintillator Detectors
Theoretical Overview:
How gamma rays are produced NaI(Tl) detectors Gamma-ray interactions with matter The maximum energy given to an electron in Compton
scattering occurs for a scattering angle of 180°, and the
Radioactive nuclei decay by emitting beta or alpha The thallium-activated sodium iodide detector, or NaI(Tl) There are three dominant gamma-ray interactions
energy distribution is continuous up to that point (since
particles. Often the decay is to an excited state in the detector, responds to the gamma ray by producing a small with matter:
all scattering angles up to 180° are possible). This energy,
daughter nucleus, which usually decays by emission of flash of light, or a scintillation. The scintillation occurs 1. Photoelectric effect known as the Compton edge, can be calculated from the
a gamma ray. The energy level sequence and therefore when scintillator electrons, excited by the energy of the incident gamma ray energy.
2. Compton effect
the gamma-ray energy spectrum for every nucleus is photon, return to their ground state. The detector crystal
unique and can be used to identify the nucleus. The is mounted on a photomultiplier tube which converts the 3. Pair production For θ = 180°:
energy levels and decay process of 22Na, 60Co and scintillation into an electrical pulse. The first pulse from the
137Cs are given in Figure 1-1. The term beta decay The photoelectric effect is a common interaction between
photocathode is very small and is amplified in 10 stages by
a low-energy gamma ray and a material. In this process
means β- (electron), β+ (positron) emission or electron a series of dynodes to get a large pulse. This is taken from
the photon interacts with an electron in the material
capture by the nucleus. the anode of the photomultiplier, and is a negative pulse. Equation 1-3
losing all of its energy. The electron is ejected with an
The NaI(Tl) crystal is protected from the moisture in the energy equal to the initial photon energy minus the
air by encasing it in aluminum, which also serves as a binding energy of the electron. This is a useful process
β-
60 Co β+ 22Na convenient mounting for the entire crystal/photomultiplier for spectroscopy since an output pulse in a detector is
2.506
EC unit. A schematic is shown in Figure 1-2. produced that is proportional to the gamma-ray energy, and:
1.173
137Cs β- as all of the energy of the gamma ray is transferred to
1.333 1.275
0.662
the detector. This produces a characteristic full-energy
1.333 peak in the spectrum that can be used for the purpose of
0 identifying the radioactive material.
137Ba
0 0 Equation 1-4
60 Ni 22Ne
The photon can scatter by a free electron and transfer an
amount of energy that depends on the scattering angle.
Figure 1-1:
Energy level sequences for 137Cs, 60Co and 22Na (energy levels in MeV) This process is called Compton scattering. The energy of
the scattered photon E′ is: The spectrum for 137Cs shows that if the gamma ray
scatters and escapes the crystal then the energy
deposited will be less than the full-energy peak
(see Figure 1-3).
Equation 1-1
where E is the incident gamma-ray energy and θ is
Figure 1-2:
the angle of scatter. The term m0c2 is the rest mass of
lllustration of a scintillation event in a photomultiplier tube
the electron, equal to 511 keV. The energy given to the
electron is:
Equation 1-2
9 www.canberra.com Nuclear measurement solutions for safety, security & the environment. 10
Experiment 1 Experiment 1
1 Gamma-Ray Detection with Gamma-Ray Detection with 1
Scintillator Detectors Scintillator Detectors
Theoretical Overview
Continued
Experiment 1 Guide:
The actual energy deposited depends upon the angle scattering interactions in the material. When the positron Photoelectric effect and Compton scattering Pair production
of scatter as described in the equations above. The comes to rest, it annihilates with an electron producing
1. Ensure that the Osprey (with the NaI(Tl) detector 11. Clear the spectrum.
spectrum shows that many pulses have energies in a a pair of 511 keV gamma rays that are produced
connected) is connected to the measurement
range below the Compton edge – called the Compton back-to-back. These can be absorbed through the 12. Replace the 137Cs source with a 88Y source.
PC either directly or via your local network.
Continuum. photoelectric effect to produce full-energy peaks at 13. Acquire a spectrum (use a count time such that
511 keV. A component due to Compton scattering can 2. Place the 137Cs source in front of the detector.
If the gamma ray does not escape the crystal and there is at least 10 000 counts in each photopeak).
also be observed. When a photon interacts with the 3. Open the ProSpect Gamma Spectroscopy
scatters again giving up its remaining energy through the 14. Use annotations (using the right click menu) to
crystal through pair production, one or both of the Software and connect to the Osprey.
photoelectric effect, then its full energy will be deposited identify the 898 keV and 1836 keV full-energy
annihilation photons can escape undetected from the
in the full-energy peak (at 662 keV for 137Cs). This is 4. Adjust the MCA settings to correspond with peaks. Also Identify the single escape peak
crystal. If one of the photons escapes undetected, then
more likely for larger crystals. those listed in Table 1-1. It is recommended from 1836 keV, which should have an energy of
this will result in a peak in the spectrum at an energy of
Pair production can occur when the gamma-ray energy 511 keV less than the full-energy peak. This is called the to use these settings throughout this manual 1836 – 511 = 1325 keV.
is greater than 1.022 MeV and is a significant process single escape peak. Similarly, if both photons escape unless otherwise specified.
15. Copy the spectrum to clipboard and paste into a
at energies above 2.5 MeV. The process produces undetected, a peak will appear 1022 keV below the full- 5. Use the software to apply the recommended Word document (provide an appropriate caption for
a positron and electron pair that slow down through energy peak, called the double escape peak. detector bias to the NaI(Tl) detector. the spectrum).
6. Set the amplifier gain such that the photopeak is 16. Save the spectrum.
close to 40% of the full range of the spectrum.
7. Acquire a spectrum (use a count time such
that there are at least 10 000 counts in the Energy calibration
photopeak). 17. Load the 137Cs and 88Y spectra.
8. Use annotations (using the right click menu) to 18. By left-click dragging a region of interest across
identify the Photopeak, the Compton Continuum each peak, determine the centroid channel for the
10 000 and the Compton Edge. 662 keV, 836 keV and 1836 keV full-energy peak.
Sample Measurement: 137Cs Reference Standard
9. Copy the spectrum to clipboard and paste into a Note down the centroid channel and uncertainty for
Word document (provide an appropriate caption each peak as presented by the tooltip in ProSpect.
7500
for the spectrum). 19. Using Microsoft Excel or another spreadsheet or
10. Save the spectrum. graphing application, enter the energy, channel
Counts
5000 Compton Continuum and the uncertainty in channel. Plot the energy vs.
662 keV Full-energy peak channel (with channel uncertainties displayed as
Table 1-1: error bars).
Standard Gain and Filter Settings for NaI 2x2 with Osprey or Lynx MCA
2500
20. Use the spreadsheet to calculate the energy
Parameter Setting
calibration coefficients. Enter these into ProSpect
Acquisition Mode PHA
using the Calibration tab for the detector.
0 LLD Mode Automatic
0 500 1000 1500
LLD % 0.1
21. Collect a 60Co spectrum and identify the energies
Energy (keV)
of the two full-energy peaks.
Polarity Positive
Figure 1-3: ULD % 100.0
Example spectrum of a 137Cs source BLR Mode Automatic
Fast Disc Shape Normal
Fast Disc Mode Automatic
Manual Fast Disc 1.0
Rise Time 1.0
Flat Top 1.0
PUR Guard 1.1
Conversion Gain 2048
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Nuclear measurement solutions for safety, security & the environment. 7
CANBERRA is part of AREVA
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The group’s offer to utilities covers every stage
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to building tomorrow’s energy model: supplying the
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and with less CO2.
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Nuclear Measurement Solutions for Safety, Security and the Environment
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