• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • No language data
  • Tagged with
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of a capture-gated fast neutron detector with pulse shape discrimination using digital pulse processing

Jastaniah, Saddig Darwish January 2003 (has links)
This study explores the use of digital pulse processing techniques for n/y pulse shape discrimination (PSD) in liquid scintillators, and the application of these techniques to a capture-gated fast neutron monitor developed using an enriched '°B-loaded liquid scintillator (BC523A). The motivation for this study has been to develop a computationally-fast digital PSD algorithm, which can be used to detect a weak neutron flux in the presence of a strong gamma ray background and to assess its suitability for use as a portable neutron monitor for fast neutron dosimetry. BC523A can operate as a full-energy neutron spectrometer when used in the 'capturegated' mode, where a characteristic capture time is observed between the proton recoil and neutron capture pulses, thus producing a very clean signature for those fast neutrons which are completely moderated within the detector volume. The use of digital waveform capture of this double-pulse sequence is a powerful technique that allows acquiring both the timestamped pulse amplitudes and the capture lifetime in a single data set. The capture-gated performance of a 105 cm' BC523A detector was investigated using fast neutrons from an Am-Be source. The measured mean neutron capture time in BC523A was 470±80 ns, which is a factor of 5 shorter than that reported for liquid scintillators loaded with natural boron. Due to its limited neutron detection efficiency, an extension of this technique to a large volume (685 cm) BC523A was developed, and provided an efficiency increase by a factor of 7. The efficiency enhancement was modelled using MCNP-4C. Good n/y separation was obtained using digital PSD applied to BC523A. The PSD figure of- merit (FOM) was investigated for various organic scintillators, and compared between digital and analogue pulse processing techniques. The application of digital PSD to the capture-gate detection mode was investigated, as an additional method for suppression of gamma sensitivity.

Page generated in 0.058 seconds