Re: Radium on Luminous Dial Watches

["Michael Stabin" <michael.g.stabin@vanderbilt.edu>]

Date: Mon, 12 Nov 2001 17:12:18 -0800

From: "Otto G. Raabe" <ograabe@UCDAVIS.EDU>

Subject: Re: Radium on Luminous Dial Watches



November 12, 2001

Davis, CA



My inquiry about the quantity of radium on the dial of pre-1950 luminous

dial watches resulted in replies that covered the range from 0.01

microcuries to 15 microcuries. I thank all those of you who responded.



Eisenbud's "Environmental Radioactivity", (3rd Ed., 1987; page 235) says,

"The radium content of men's wristwatches ranged from about 0.01 to 0.36

microcuries (from Seelentag and Schmier, 1963; Radiological Health Data 4,

209-213). [I don't have the S&S reference.] The Eisenbud and Gesell 4th Ed.

repeats the same information. On the other hand, Ron Kathren's

"Radioactivity in the Environment", page 79, lists 0.1 to 3 microcuries for

radium dial watches. "Living with Radiation: The First Hundred Years" by

Paul Frame and William Kolb, 2nd Ed. (2000), page 67, indicates a typical

value of 0.1 microcuries for a watch. The 10CFR30 limit is 3 microcuries.

Military watches of WW II apparently were among the more robust and in the

range from 1 to 3 microcuries. 



Some responders suggested looking at the radium dial painter studies. I

have read most of the main articles and books about the dial painters, but

have found no quantitative indication of the activity per watch. Also,

there is apparently very little known about the exact composition of the

paint. Each company may have had their own proprietary formula.



Others mentioned the dose rate at the watch surface. Among the highest was

the Rolex Oyster Perpetual with 10 mR/hr in front and 0.5 mR/hr in back.

One person reported owning a Tissot Swiss watch purchased in Europe in

1962. He wore it for 12 years until he measured the top surface dose rate

at 2 mR/hr.  

   

The radium dial watches were manufactured primarily before 1950. If any of

you have one of these watches and a calibrated counting system, please make

a measurement and let us know what you find. To find one of these watch,

such as the famous Elgin radium dial watches, check out E-Bay or

http://members.aol.com/vwws/vwws.html



Sincerely,



Otto



**********************************************

Prof. Otto G. Raabe, Ph.D., CHP

Center for Health & the Environment

(Street Address: Bldg. 3792, Old Davis Road) 

University of California, Davis, CA 95616

E-Mail: ograabe@ucdavis.edu

Phone: (530) 752-7754   FAX: (530) 758-6140

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