SV: [ RadSafe ] GammaVision gamma spectroscopy software

[Olsson Mattias :MSO]

Hi,

Without being able to go into very much detail I believe Gammavision does this in its standard report:

- Summary of nuclides in sample on the last page gives you the identified nuclides and their activity values. The values may be calculated EITHER on one energy line or several.
- It it quite crucial how your nuclide library is set up. In the library, you can set flags for each gamma energy. The energy at the top of the list is always a key line, meaning that the whole nuclide is discarded unless this energy is found. You can mark more energies as additional keylines. You can also set the a flag if you don't wish an energy to be included in the average calculation. I have found it very wise to use this flag to avoid influence of misinterpreted low yield gammas. In Summary of library peak usage you can see which flags are set for each energy and nuclide (at the end of each row). The flag codes are explained after the list. I would think about with how i set my K and A flags.
- If you have peaks with zero counts in the Identified peak summary, do you really have them detected in the Summary of peaks in range? I believe the Identified peak summary prints every energy in the library, no matter if it is detected or not. If a peak is not detected you would get zero.
- An automatic interference correction is also done. I have not looked closer into the effects of that... I guess it could cause some funny looking things in the report but it has not been an important issue to me yet.

Best regards,
Mattias Olsson, Forsmark NPP

-----Ursprungligt meddelande-----
Från: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] För Michael McNaughton
Skickat: den 4 juni 2009 00:43
Till: radsafe at radlab.nl
Ämne: [ RadSafe ] GammaVision gamma spectroscopy software


Dear Radsafers

I would appreciate some help on how to interpret the detailed "Gamma 
Spectroscopy" pages printed by the GammaVision Report Writer.

For example, in the "Summary of Library Peak Usage," when several 
peaks are listed for a particular radionuclide, I expect to see the 
activity listed for each peak, and then I expect the "Average 
Activity" to be an average of some or all of the activities for 
individual peaks. Also, I would expect to see the peaks that 
contribute to the final activity to be marked to indicate: "This peak 
is used in the nuclide activity average." In some cases, I do indeed 
see what I expect. In other cases, I see several peaks listed with an 
activity identical to the average, including peaks that are marked: 
"Peak fails sensitivity test" or "Peak activity lower than counting 
uncertainty range".

I am also puzzled by the "Identified peak summary", for example for 
Ra-226. Many of the peaks used by Ra-226 are from Bi-214 or Pb-214. 
However, the "Net Area Counts" for Ra-226 are very different from 
those for Bi-214 or Pb-214. For example, I have a case for which the 
area of the 1408-keV peak is listed as 0.00 counts for Pb-214 and 
1206.11 counts for Ra-226. Also, the 609-keV peak is listed as 0.00 
counts for Bi-214 and 983.77 counts for Ra-226.

mike


Mike McNaughton
Los Alamos National Lab.
email: mcnaught at LANL.gov or mcnaughton at LANL.gov
phone: 505-667-6130; page: 505-664-7733