Department of Chemistry 1953 ID Number 1994.0125.57 accession number 1994.0125 catalog number 1994.0125.57 Object Name gamma-ray standard, secondary, Co60 Physical Description plastic (overall material) cotton (overall material) aluminum (overall material) paper (overall material) liquid with cobalt 60 (overall material) glass (overall material) Measurements overall (transparent, capped plastic container): 3 3/4 in x 7/8 in 9.525 cm x 2.2225 cm glass ampoule: 3 in x 5/8 in 7.62 cm x 1. A glued-on paper label, has printed the following: “National Bureau of Standards / Co60 Gamma Ray Standard / 0.685x106 dps on Oct.1, 1953” Location Currently not on view Credit Line Rensselaer Polytechnic Institute. The current cobalt 60 installed base is about 195 MCi. Cobalt, though widely dispersed, makes up only 0.001 percent of Earth’s crust.It is found in small quantities in terrestrial and meteoritic native nickel-iron, in the Sun and stellar atmospheres, and in combination with other elements in natural waters, in ferromanganese crusts deep in the oceans, in soils, in plants and animals, and in minerals such as cobaltite, linnaeite, skutterudite. About two-thirds of the ampoule volume contains a slightly pinkish-tinged liquid. KEYWORDS Cobalt 60, sources, irradiators, gamma processing, trends, growth INTRODUCTION Since gammas commercial introduction in the 1960s, the growth in cobalt 60 usage has been remarkable. Herbert Clark, Rensselaer Polytechnic Institute.) Flame sealed glass ampoule, 3” long, 5/8” diam., held by base and tip in a transparent cylindrical plastic container with black-painted aluminum screw cap, 3 ¾” long, 7/8” diam. For details on survey instrument calibration, see: Detailed description of Cobalt 60 secondary gamma-ray standard, 0.685x10E6 dps, Object 1994.0125.57 (One of the accompanying photographs provided by donor, Prof. NIST maintains the primary radiation sources, and makes available and/or certifies secondary sources for instrument calibration. National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards (NBS). A standard source is a radiation source exhibiting a disintegration (e.g., disintegrations per second or dps), emission or exposure rate certified by or traceable to the U.S. A radioactive source (not necessarily calibrated) is used to confirm the satisfactory operation of an instrument. 58 Instruments used for radiation detection, measurements, or surveys need to be calibrated periodically. Object Details National Bureau of Standards Description Background on secondary gamma-ray standards, Object IDs 1994.0125.55.
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