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Disc & Laminate Sources

NOTE: All sources are +/- 20% nominal activity; +/- 5% activity calibration for gamma sources is available at extra charge. See here. Contact us for pricing or additional information.

Disc sources are available in 1" and 2" diameter plastic disc with the 1" being standard and other sizes on special order.

The Po-210 alpha source is of open window construction with the source material bonded to the surface of a silver foil mounted in the recess of the plastic disc. This design yields excellent emission of alpha particles without window losses.

Plastic laminates provide a convenient alternative packaging being easy to handle and store. The standard laminates have a transmission window of  0.005" and produce minimum attenuation for photons and higher energy beta particles.

Now the C14, FE55 and Po210 sources have a thin, aluminized Mylar window. Order as, for example, C14LMW - Laminated Mylar Window

Two sizes are available, 3.75"x2.25", and a 1" diameter circular disc. Other sizes are available; just let us know and we will send you a quote. Low energy x-ray, beta and alpha sources can be produced with a 80 gm/cm2 aluminized Mylar window offering excellent transmission for Fe-55, C-14 and Po-210.




GM Resolving Time Set
This set is used for determining the resolving time of GM Counters. It consists of three half discs, two of which contain 5 microcuries of Tl-204 plus a third half disc with no activity. The count-rate of each half disc plus the blank (to maintain constant geometry) is measured and then both active half discs are combined for a measurement with high count-rate. The counting loss may now be calculated by adding the rates from each half disc and comparing the result to the count-rate with both halves combined.


The RSS-3 contains 1 each Po-210, Sr-90 and Co-60 emitting a range of alpha, beta and gamma radiation's. This set is ideal for demonstration and introductory nuclear labs covering basic characteristics of radiation. The Co-60 is 1.0 uCi and the Po-210 and Sr-90 are 0.1 uCi activity.




Containing 1 each Cs-137, Co-60, Sr-90, Tl-204 and Po-210, the RSS-5 provides a wide of alpha, beta and gamma emissions making it a popular choice for nuclear science instruction The set contains two beta emitters, two beta/gamma emitters and one alpha source for in-depth studies of radiation. The Cs-137 is 5 uCi, the Po-210 and Sr-90 are 0.1 uCi activity and the Co-60 and Tl-204 are both 1 uCi.


Designed for gamma spectroscopy, the RSS-8 contains eight different gamma emitting isotopes covering the entire energy range from 32 to 1333 keV. Also included in the set is a mixed source of Cs-137 and Zn-65 which students may use to identify an “unknown” isotope. The set consists of Ba-133, Cd-109, Co-57, Co-60, Cs-137, Mn-54. Na-22 and Cs/Zn. Source activities are all 1 uCi, except the Cs/Zn source, which is 0.5 uCi Cs and 1 uCi Zn.



Due its relatively short half-life, the Po-210 alpha source must be replaced on a regular basis. Currently this is the only alpha emitting material available as a NRC Exempt Quantity which may be held without a radioactive material license.


Radioisotope sources are available individually or packaged as sets of three, five, and eight in convenient storage boxes. These items are exempt sources and of nominal activity to provide a safe, yet inexpensive supply of radioactive material for educational and commercial use.When shipping or storing multiple gamma sources, to reduce reduce radiation levels we recommend using Lead Shields.

Standard individual sources for alpha, beta and gamma emissions are available in the following isotopes.



ActivityHalf-lifeEmissionsEnergies (keV)
Ba133S11uCi.10.7 yearsGamma81.0, 276.3, 303.7, 355.9, 383.7
C14S1010uCi.5730 yearsBetaβ156.5
Cd109S11uCi.453 daysGamma88.0
Co57S11uCi.270 daysGamma122.1, 136.4
Co60S11uCi.5.27 yearsGamma, Beta1173.2, 1332.5, β317.9
Cs137S.20.2uCi.30.1 yearsGamma, Beta32, 661.6, β511.6, β1173.2
Cs137S.50.5uCi.30.1 yearsGamma, Beta32, 661.6, β511.6, β1173.2
Cs137S11uCi.30.1 yearsGamma, Beta32, 661.6, β511.6, β1173.2
Cs137S55uCi.30.1 yearsGamma, Beta32, 661.6, β511.6, β1173.2
Cs/ZnS1uCi.Mixed"Unknown"32, 661.6, 1115.5
Eu152S11uCi.13.5 YearsGamma, BetaMultiple energies
Fe55S100100uCi.2.73 yearsX-ray, Beta5.9, 6.5, β231.4
Mn54S11uCi.312 daysGamma, Beta834.8, β542.2
Na22S11uCi.2.6 yearsGamma1274.5, 511
Po210S0.1uCi.138 daysAlpha 5304.4
Sr90S0.1uCi.28.8 yearsBetaβ546
Tl204S11uCi.3.78 yearsBetaβ763.7
Zn65S11uCi.244 daysGamma, Beta1115.6, β236.34 β1351.9

Other activities are available on special order to the maximum NRC Exempt Quantities.

Gamma sources may be order as Calibrated against the NIST Mixed Gamma Standard, SRM 4275C-125.


 Canadian customers with questions about exempt sources

Canadian Nuclear Safety Commission
Nuclear Substances and Radiation Devices Licensing Division

280 Slater Street
P.O. Box 1046
Station B
Ottawa, ON, K1P 5S9


The toll-free line to our Division is 1-888-229-2672 and the general e-mail box is licensees@cnsc-ccsn.gc.ca.  

Inquiries to the e-mail or phone number will be distributed to a member of the licensing staff for response.
Other source activities may be available as exempt quantities on special order. Gamma sources are also available as calibrated. Contact factory for information and pricing.

Letter to International Customers concerning Cesium 137 (Cs137) Sources

Click here

Note: For both Domestic and International Source Orders - Activities of gamma emitters over 5 to 10 uCi MAY require lead shielding, either LSD1, LSD4 or LSD5. If required, the lead shield and appropriate price will be added to your order.

For International Source orders - see special notice in What's New - here

These sources are supplied as plastic discs or as thin plastic laminates. With the exception of the alpha source, the small quantity of radioactive material is sealed in the plastic with epoxy to prevent leakage and contamination. The transmission window is sufficiently thin to transmit both beta and gamma emissions without undue absorption.

Canadian customers having questions about exempt sources, click here

How to Dispose of Exempt Sources - FOR INTERNATIONAL CUSTOMERS Click here

QS_RLBR.GIF (2244 bytes)

NRC 30.18 Exempt quantities (narrative)
NRC 30.71 Schedule B Exempt Quantity Radionuclide Regulations (Table)
MSDS/Data Sheet for Sources

QS_RLBR.GIF (2244 bytes)


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