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Answer to Question #1475 Submitted to "Ask the Experts"Category: Historical Issues/Applications The following question was answered by an expert in the appropriate field: Q
Has 137Cs been uses to paint the dials on aircraft instruments in the past, circa the 1940s and 1950s?
A
I am not aware of 137Cs being used for self-luminescent dial applications. The 137Cs
beta decay has a 662 kiloelectron volt gamma ray associated with 85% of
the decays, thus would present an external hazard. However, that didn't
stop the use of 226Ra in this application from c1910 thru
the c1960 time frame, for hundreds of thousands of watch, clock, and
aircraft dials. However, 226Ra has an alpha emission and many similar decay products and is no doubt more efficient in light production. I know 147Pm was used, and tritium (3H) is still used in such applications, for example, watch dials and EXIT signs.
David J. Allard, CHP
Answer posted on 14 December 2001. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.
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