Re: Specific Gamma Ray Constant for Ra-226

[John Andrews <andrewsjp@chartertn.net>]

I believe that the old rule, perhaps the original definition, was that 1 

Ci of Ra-226 in equilibrium with it's daughters gives 1 R/hr at 1 YARD, 

 not 1 meter.  Hence the ratio of 0.84 I found in my old Rad Health 

Handbook for the dose rate at 1 meter.  The value of 0.84 was later 

revised to be 0.825 .



John Andrews

Knoxville, Tennessee



BERNARD L COHEN wrote:



>	There was a very old rule of thumb which, I believe, derived from

>radium. It was 1 Ci gives 1 R/hour at 1 meter (the R was Roentgen, but it

>is close to Rad). This would support the 0.825 figure.

>

>Bernard L. Cohen

>Physics Dept.

>University of Pittsburgh

>Pittsburgh, PA 15260

>Tel: (412)624-9245

>Fax: (412)624-9163

>e-mail: blc@pitt.edu

>

>

>On Mon, 3 Mar 2003, Toli Mikell wrote:

>

>  

>

>> While researching the specific gamma ray constant for radium-226, I noticed two different figures,  0.825 R/hr at 1m/Ci  and 0.0121138 R/hr at 1m/Ci.  Can someone provide some clarity on this for me?  The issue in question is about Ra-226 needles.  You may respond privately at tmikell@excite.com. Thanks, Toli Mikell

>>

>>    

>>





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