Accession Number : ADA519265


Title :   A Two-Channel Phoswich Detector for Dual and Triple Coincidence Measurements of Radioxenon Isotopes


Descriptive Note : Conference paper


Corporate Author : OREGON STATE UNIV CORVALLIS


Personal Author(s) : Farsoni, Abi T ; Hamby, David M ; Ropon, Kimberly D ; Jones, Sean E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a519265.pdf


Report Date : Sep 2007


Pagination or Media Count : 11


Abstract : As part of the Comprehensive Nuclear Test Ban Treaty, the International Monitoring System (IMS) has been established for monitoring xenon radioisotopes in the atmosphere to detect atmospheric or underground nuclear explosions. Experimental results from the Automated Radioxenon Sampler/Analyzer (ARSA) system, developed at Pacific Northwest National Laboratory, show that the system is capable of detecting very low concentrations of the fission product radioxenon isotopes (133)Xe, (133m)Xe, (131m)Xe and (135)Xe. To build a more practical radioxenon detection system as sensitive as the ARSA system but with reduced cost, size, power consumption and complexity, several detection systems have been developed or are currently under development. It has been shown (McIntyre et al. 2004) that triple coincidence measurements of beta, conversion electons (CE) and x-ray from the radioxenon gas provides a significant reduction of Compton scatter interference in the 30-keV line and therefore much lower (2-3 orders of magnitude) concentrations of (133)Xe can be detected even with a high radon background. The triple coincidence measurement eliminates the need for additional separation columns and traps (required for removing the background radon) and allows for reduced passive shielding as well, thus reducing the size and power consumption of the system. In this paper, a two-channel phoswich detector is introduced and studied. The detector consists of a thin hollow disk (with 2 mm thickness and 76.2 mm diameter) as the xenon gas cell, surrounded by two identical planar triple-layer phoswich detectors. This design provides a solid angle of about 3.4 pi for the gas cell, close to that of the ARSA system (tilde 3.5 pi). The planar shape of the detectors has several important advantages, among which are the reduced cost due to its simplicity, and because it has a minimum non-uniformity in light collection efficiency, will not unreasonably degrade the beta or gamma energy resolution.


Descriptors :   *DETECTORS , *RADIOACTIVE ISOTOPES , NUCLEAR EXPLOSION TESTING , RADON , ANALYZERS , XENON , FISSION PRODUCTS , UNDERGROUND EXPLOSIONS , SYMPOSIA , CONCENTRATION(COMPOSITION)


Subject Categories : Miscellaneous Detection and Detectors
      Isotopes


Distribution Statement : APPROVED FOR PUBLIC RELEASE