GSWG Reports

The report presented during the ICRM 2011 conference in Tsukuba is included here: ICRM_GSWG_Report_2011.doc

The report presented during the ICRM 2009 conference in Bratislava is included here: ICRM_GSWG_Report_2009.doc

The report presented during the ICRM 2007 conference in Cape Town is included here: ICRM_GSWG_Report_2007.doc

The report presented during the ICRM 2005 conference in Oxford is included here: ICRM_GSWG_Report_2005.doc

Coincidence summing correction exercise

An intercomparison of the methods used for computing the coincidence summing corrections is currently organized in the frame of the Gamma Spectrometry Working Group of the ICRM.
Nowadays, there are several ways of computing these corrections and each method has advantages and drawbacks (accuracy, easiness, speed, …) that are compared during this action.
In a first step, the comparison was restricted to point sources and to two radionuclides (¹⁵²Eu and ¹³⁴Cs). The same decay scheme and photon emission intensities was used by all the participants (NUCLEIDE database) to avoid bias linked to data discrepancies. The results are expressed as the coincidence summing correction factors for the multi-energetic nuclides for several energies and several source-to-detector distances.
The first part of the action is now over and the working group meeting in February 2009 made its synthesis. These results have been presented during the ICRM2009 conference and are included in an article:
Intercomparison of methods for coincidence summing corrections in gamma-ray spectrometry, by M.-C. Lépy and all the participants of the intercomparison, to be published in Applied Radiation and Isotopes, available online Feb 2010.

The second step of the exercise is devoted to the case of volume sources using the same experimental setup as in the first part of the comparison, for the same two radionuclides (¹³⁴Cs and ¹⁵²Eu), but with different geometrical conditions: three volumes were considered, whose container diameter was smaller, equal or larger than the detector diameter. These containers were measured in three geometrical conditions: without absorber and with a Plexiglas or copper screen to examine the influence of X-rays. Experimental corrections were determined using the ratio between the activity derived from the processing of individual peaks (without correction) and the true activity of the source.
Fifteen laboratories participated in the action and more than 20 series of results were obtained, using 18 different methods. In this step, the dispersion of results was wider that in the case of point sources. The first results were presented and discussed during the workshop held in October 2010 and will be presented during the next ICRM conference in September 2011.

Exercise coordinator: Marie-Christine Lépy (LNE/LNHB, France)

File of presentation of the exercise is available here: Proposal….doc

Monte Carlo codes intercomparison exercise

The aim of the exercise is to test the possible differences between Monte Carlo codes in order to assess the intrinsic uncertainties of such calculations, due to the different approaches to particle tracking and the nuclear and material data used for it. 
In accordance with its objective the exercise does not involve any reference to the experimental data and simply confronts the codes one with another, as they are applied to the calculation of full energy peak and total efficiencies for a precisely defined and very schematic model of a HPGe detector and the sample. Since there is no experimental data to compare the results of the codes against, this exercise only tests their mutual compatibility and not their absolute performance.

The results of the exercise will provide useful information for future intercomparisons involving the application of Monte Carlo codes to efficiency transfer and coincidence summing correction calculations.

Exercise coordinator: Tim Vidmar (Jozef Stefan Institute, Ljubljana, Slovenia)

Files of presentation of the exercise are available here: Instructions.doc; Report.doc; Report.xls

Dr Tim Vidmar had an oral presentation during the 2007 ICRM conference to present the action and its results. The relevant paper “An intercomparison of Monte Carlo codes used in gamma-ray spectrometry” is published in Applied Radiation and Isotopes, Vol 66, Issue 6-7, p 764-768, 2008.

No further developments are presently planned and this action is now completed.

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