Low-resolution gamma-ray spectrometry for an information barrier based on a multi-criteria template-matching approach

Abstract

Gamma-ray spectrometry has been successfully employed to identify unique items containing special nuclear materials. Template information barriers have been developed in the past to confirm items as warheads by comparing their gamma signature to the signature of true warheads. Their development has, however, not been fully transparent, and they may not be sensitive to some relevant evasion scenarios. We develop a fully open template information barrier concept, based on low-resolution measurements, which, by design, reduces the extent of revealed sensitive information. The concept is based on three signatures of an item to be compared to a recorded template. The similarity of the spectrum is assessed by a modification of the Kolmogorov-Smirnov test to confirm the isotopic composition. The total gamma count rate must agree with the template as a measure of the projected surface of the object. In order to detect the diversion of fissile material from the interior of an item, a polyethylene mask is placed in front of the detector. Neutrons from spontaneous and induced fission events in the item produce 2.223 MeV gamma rays from neutron capture by hydrogen-1 in the mask. This peak is detected and its intensity scales with

Nuclear disarmament verification based on (n,γ) reaction using physical encryption technology

“…For each sam ple, 100 ir ra di a tion mea sure ments are made at a to tal source flux of 5×10 6 and an ex am ple of a typ i cal fin ger print from a tem plate is shown in fig. 2 along with some sam ples to be tested.…”

“…The ro bust ness of the sys tem un der dif fer ent SNR is an a lyzed with a Monte Carlo sim u la tion in which the neu tron source flux is set to be 5×10 6 . As shown in fig.…”

“…To pro tect sen si tive data, pro posed in spec tion meth ods pri mar ily em ploy in for ma tion bar rier technol o gies, such as low-res o lu tion gamma ra di a tion imag ing [6], zero knowl edge pro to col [7,8], and res onance flu o res cence tech nique with en crypted foils [9]. Most meth ods pro posed so far are still vul ner a ble to spoof ing or leak ing sen si tive in for ma tion [10]: -the slightly in tru sive ver i fi ca tion tech nol ogy can eas ily iden tify fraud sce nar ios, but it in creases the risk of sen si tive in for ma tion be ing leaked, -as a re sult of the com plex elec tronic cir cuit sys tem, the mea sure ment data is more vul ner a ble to eavesdrop ping and tam per ing, and -the lim ited in for ma tion ob tained through the in forma tion bar rier de tec tion leaves the ver i fi ca tion party (in spec tors) with in suf fi cient con fi dence in the authen tic ity of the de clared nu clear war heads, such as through some pas sive mea sure ment tech niques [11].…”

A New Era of Nuclear Criticality Experiments: The First 10 Years of Radiation Test Object Operations at NCERC

“…101 Princeton University performed measurements with NaI for template matching to provide information barriers within treaty verification. 102,103 The University of Michigan performed Rossi-α measurements with OS and 3 He detector systems (shown in the bottom-right of Fig. 17…”