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RE: Radium on Luminous Dial Watches
Date: Wed, 14 Nov 2001 08:41:44 -0500
From: "Kolb, William (WKOLB)" <WKOLB@arinc.com>
Subject: RE: Radium on Luminous Dial Watches
Here are some measurements made with the S.E. International, Inc. Inspector
GM counter that are traceable to radium standards. A log-log calibration
plot of CPM Vs four radium standards ranging from 0.0001 to 0.1 uCi was
used to estimate the radium content. The same geometry was maintained
throughout. All measurements were made without watch crystals and, most
cases, the dial face alone was measured. I have no idea when any of these
watches were made.
For comparison, the 0.01 uCi Ra standard reads about 4.4 mR/hr against the
ion chamber window of a Victoreen 440RF/D meter. The 0.1 uCi Ra standard
reads about 36 mR/hr. The hottest of these watch dials reads about 40 mR/hr
when placed directly against the chamber window. Mileage obviously varies.
Name Configuration Radium (uCi)
Lucerne dial 0.0053
Tudor Oyster dial 0.0061
The Bell dial 0.0063
Milus dial 0.0071
Benrus dial 0.019
Cyma dial 0.039
Hamilton dial 0.047
Nivia dial 0.052
Witnauer dial + hands 0.053
Illinois dial + hands 0.066
Rolex dial 0.091
Ord. Dept. USA dial + hands 0.099
Bulova dial 0.12
bill
WM Kolb
ARINC
410-266-4017
-----Original Message-----
From: Otto G. Raabe [mailto:ograabe@UCDAVIS.EDU]
Sent: Monday, November 12, 2001 8:12 PM
To: RADSAFE Listserver
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.
SNIP
I thank all those of you who responded.
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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