AutoMGA++: a new acquisition and data review software for the use of MGA code
Jean-Luc Dufour, Anne-Laure Weber, Pierre Funk, ESARDA, Stockolm, 13-15 mai 2003
In the framework of French domestic safeguards, measurements are performed by inspectors from IRSN/DSMR to verify operator’s declaration on uranium and plutonium. For this purpose, MGA++ code has been used for many years by the inspectors to measure uranium enrichment and plutonium isotopic composition. This paper presents new acquisition and data review software that integrates automatically MGA++ analysis (uranium and plutonium) developed by IRSN/DSMR. It has been called AutoMGA++, since it is based on the ORTEC version of MGA code: MGA++. The feedback gained from direct MGA++ measurements showed that the duration of the measurement to obtain a good gamma ray spectrum is a key factor for the accuracy of the result. The developer of the code provides a simple criterion to decide when to stop the acquisition, based on the total count in the spectrum with a recommended value greater than 106. This criterion is just a general indication and in many cases, it is not appropriate. For instance, the MGA++ analysis may be accurate with less count than 106. On the other hand, for spectra with high Compton scattering, it may be necessary to increase the total count in the spectrum. Keeping in mind that the total count is directly related to the duration of the measurement, the main objective of AutoMGA++ is to optimize the duration of the measurement as regard with results provided by MGA++. The basic idea is to perform a cumulative acquisition, based on GammaVision software from ORTEC and to perform periodically a MGA++ analysis. AutoMGA++ enables to perform this process completely automatically with the saving of all data. In order for the user to decide when to stop the process, a graphical views of MGA++ results is available. Other features are available in AutoMGA++ in order to ensure the quality of the data acquired, by looking graphically at information in the cumulative spectra: region of interest, total counts… Since its development, AutoMGA++ has been used intensively. It is not only a powerful tool to optimize acquisition duration (and subsequently to improve the quality of the measurements) but also an adequate software for the testing of the code performance. At that stage, only MGA++ routine is integrated but it is intended to extent its capabilities for other analysis codes.