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Radionuclide monitoring is a proven means of non-intrusive verification of the nuclear test ban treaty. In addition to that, the potential use of radionuclide monitoring spans beyond the detection of nuclear test explosions, since radionuclides can also be released and detected from operations of nuclear fuel cycle facilities, such as the reactor operation and nuclear reprocessing of plutonium production.

In this work, we consider the use of coincidence and anticoincidence techniques as a means to increase the sensitivity in radionuclide monitoring, in terms of improved minimum detectable amount for radionuclides of interest to filter stations used in radionuclide monitoring. In particular, a multi-detector setup is currently being prepared for the evaluation of the technique, and to provide validation data for a coincidence detector simulation codes.

In this presentation, we will describe the multi-detector setup assembled for enabling the evaluation of various types of spectrometry, including 1) gamma-gamma coincidence (from dual detectors and up to five High Purity Germanium (HPGe) detectors), 2) anticoincidence using BGO active shield with single HPGe detector, as well as use of multiple detectors in add-back mode, i.e. simply using the combined detector volume for increased efficiency of single gamma rays. We will present the results of measurements of a calibration sample, and provide a discussion on the advantages and disadvantages of the tested techniques in the context of radionuclide monitoring.