Accession Number : ADA262550


Title :   Construction and Testing of a Neutron and Gamma Spectrometry System Using Pulse Shape Discrimination with an Organic Scintillator


Descriptive Note : Master's thesis


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING


Personal Author(s) : Pope, Robert S.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA262550


Report Date : MAR 1993


Pagination or Media Count : 207


Abstract : The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/ gamma sources used were 78-mCi and 4.7-Ci 239PuBe sources, while 4.7-micro-Ci and 97.6-micro-Ci 22Na gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the incident neutron and gamma spectra, respectively. FORIST, which was written for a CDC computer, was modified to run on a VAX 6420. The experimental spectra were compared to those in the literature. The locations of the peaks in the 239PuBe spectrum agreed with the literature to within 8.3%, the 239PuBe gamma spectrum agreed to within 0.7%, while the 22Na gamma spectrum agreed exactly. Uncertainties in the detection system and unfolding procedure are on the order of 5-10%. This thesis is intended to be a summary of the relevant literature and a user's guide to the PSD spectrometer.... Neutron unfolding code, Gamma spectrometry, Neutron spectrometry, Pulse shape discrimination.


Descriptors :   *SPECTROMETRY , *ORGANIC MATERIALS , *SCINTILLATION , *NEUTRON DETECTORS , *GAMMA SPECTROMETERS , TEST AND EVALUATION , UNCERTAINTY , COMPUTERS , ENERGY , SHAPE , THESES , PROTONS , ELECTRONS , SPECTRA , PULSES , PHOTONS , CALIBRATION , RECOIL , BERYLLIUM , DISCRIMINATION , PLUTONIUM , NEUTRON SPECTROMETERS.


Subject Categories : ISOTOPES
      NUCLEAR INSTRUMENTATION
      OPTICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE