Re: Acceptable P-32 monitoring methods

[xug2@rpi.edu (George Xu)]

I agree with Sue and Wes.  But there is one thing we need to remember too:
the survey limits are set for "removable" contaminations and one has to take
swipes to demonstrate compliance in CERTAIN situations.   Now, the swipes
for P-32 can also be counted on a proportional counter which detects both
gross beta and alpha radiation (LSC identifies P-32).  In summary, GM
provides a quick check for whether or not a spill has occurred or for a
large area survey before one leaves the lab, and swipe sampling allows for
quantitative measurement of "removable" contamination over a relatively
smaller region (hot spot).   For counting swipes, LSC is used if you want to
identify P-32, and a proportional counter may be used (it's cheaper) if you
know P-32 is the only beta source used in a lab (by checking your
inventory).  Some of the students try to tell beta contamination from gamma
radiation by placing a thick plastic in front of the GM.  If does work for
P-32 becuase the 1.71 MeV beta causes a lot of bremss. x-rays which are
still detected by a GM. 

George Xu
RSO
Rensselaer Polytechnic Institute
Troy, NY 12180

Email: xug2@rpi.edu


  >I can't imagine using LSC wipes in place of a GM for P-32 
>contamination.  While LSC can count P-32 samples, it is not very 
>useful for performing surveys (as Sue's example points out).  
>
>Not only is the GM the ideal detector (but stay away from side window 
>probes), it is much cheaper, cleaner and faster than LSC.  If there 
>is only a little use of P-32, remember that GMs can come in very 
>small and cheap sizes.  
>
>Wes
>
>> Date sent:      Thu, 22 May 97 08:48:58 -0500
>> Send reply to:  radsafe@romulus.ehs.uiuc.edu
>> From:           "Michel, Rene" <rmichel@iastate.edu>
>> To:             Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
>> Subject:        Acceptable P-32 monitoring methods
>
>> 
>> Radsafers:
>> 
>> I am interested in obtaining an estimate of  the percentage of radiation 
>> safety offices that require workers to use portable monitoring instruments 
>>  (such as GM counters) while working with P-32 in biological laboratories. 
>>   I'm aware that at some institutions swipes are accepted as an alternative 
>>  means for detecting P-32 contamination.
>> 
>> Please, let me know if portable monitoring instruments are the only method 
>> accepted for P-32 monitoring at your institution, or
>> if either portable monitoring instruments or LSC swipes are accepted.
>> 
>>  -Rene
>> 
>> Rene Michel, Health Physicist
>> Iowa State University
>> rmichel@iastate.edu
>> 
>*********************************************************************
>Wesley M. Dunn, CHP                        512-834-6688
>Deputy Director, Licensing                 512-834-6690 (fax)
>(Texas) Bureau of Radiation Control        wdunn@brc1.tdh.state.tx.us
>*********************************************************************
>
>