Accession Number : ADA504084


Title :   Effect of Advanced Synthetically Enhanced Detector Resolution Algorithm on Specificity and Sensitivity of Portable High Purity Germanium Gamma Detector Spectra


Descriptive Note : Master's thesis


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS


Personal Author(s) : Bell, LaTosha M.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA504084


Report Date : JUN 2009


Pagination or Media Count : 108


Abstract : The ability to identify special nuclear material is one of the necessary prevention mechanisms for preventing proliferation of special nuclear materials. Additionally, if a nuclear event were to occur, information about the nuclear material used may be extracted from gamma spectra, provided it is obtained quickly and accurately. This can be made possible with the use of the exceptional resolution of the HPGe detector. This experiment applied the Advanced Synthetically Enhanced Detector Resolution Algorithm (ASEDRA) to a portable HPGe detector's spectra, to investigate whether improvements in specificity and sensitivity can be obtained. This method has been used to improve performance of NaI(Tl) spectra. In this work, measurements of Cd-109, Co-57, Eu-152, Sb-125, Eu-154, and Eu-155 spectra were used as ground truth gamma emissions. The HPGe spectra were analyzed using ASEDRA and ORTEC's Genie(trademark), a program used by many in the nuclear weapons community for spectroscopy. Genie(trademark) was used as a benchmark for comparison in this experiment. The number of positive and false positive peaks identified by each program was used for comparison, based on ground truth peaks, which are the thirty-one known peaks based on the sources used in the experiment. The results of this work show that Genie(trademark) always locates more ground truth peaks than ASEDRA and that ASEDRA identifies fewer false positive peaks than Genie(trademark) at all but three of the measurement times. In addition, the performance parameter of Genie(trademark) is higher than ASEDRA at short measurement times, implying that ASEDRA does not provide additional spectral information at shorter measurement times. The application of ASEDRA to experimental spectra does not provide any improvements in specificity or sensitivity, as compared to Genie(trademark).


Descriptors :   *ALGORITHMS , *GAMMA SPECTROMETERS , *HIGH SENSITIVITY , PAIR PRODUCTION , RADIOACTIVE ISOTOPES , COMPTON SCATTERING , GAMMA RAY ABSORPTION COEFFICIENTS , GAMMA RAYS , THESES , VERIFICATION , GERMANIUM


Subject Categories : CHEMICAL, BIOLOGICAL AND RADIOLOGICAL WARFARE
      NUCLEAR WARFARE
      MISCELLANEOUS DETECTION AND DETECTORS
      NUCLEAR PHYSICS & ELEMENTARY PARTICLE PHYSICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE