Spectrum Techniques Cs-137 (0.1 µCi) Sealed Check Source Disc - S/N NOV 2002 (#20905)
Manufacturer: Spectrum Techniques
Isotope: Cesium-137 (Cs-137)
Original Activity: 0.1 µCi (3.7 kBq) as of November 2002
Current Activity (as of November 2026): Approximately 0.058 µCi (2,133 Bq) based on a 30.2-year half-life
Serial Number: NOV 2002 (Handwritten inventory number: #20905)
Dimensions: 1 inch (25.4 mm) diameter x 1/8 inch (3.2 mm) thick sealed plastic disc
Regulatory Status: USNRC and State License Exempt Quantity (10 CFR 30.71, Schedule B)
This is a sealed Cs-137 calibration check source disc manufactured by Spectrum Techniques in November 2002. Sealed inside a durable, standard 1-inch plastic disc, it is designed for verifying the operation of Geiger-Muller counters and performing energy level calibration on gamma spectrometers (such as the Radiacode 101, 102, 103, and Atom Fast) using the prominent 661.7 keV gamma photopeak of Cs-137 (Ba-137m) and the 32 keV barium X-ray peak.
Because Cs-137 has a half-life of 30.2 years, approximately 57.6% of the original activity remains after 24 years, leaving roughly 0.058 µCi. It remains a strong, reliable beta and gamma check source for testing detector response and calibrating gamma spectroscopy instruments.
This item is a U.S. Nuclear Regulatory Commission (USNRC) and Agreement State License Exempt Quantity under 10 CFR 30.18 and 10 CFR 30.71, Schedule B (exempt limit for Cs-137 is 10 µCi).
Coin and deviced not included - Metal tin case included
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