A scintillation counting system has been constructed with the use of BC-400 and EJ-212
series plastic scintillators along with a subminiature photomultiplier tube to investigate
the effect of increasing plastic scintillator thickness on system-integrated counts.
Measurements have been carried out using four different gamma sources with different
energies ranging from 6keV to 1.332MeV and a Ni-63 beta source of maximum energy
of 66keV. A simulation was also carried out in MCNP4a to verify the number of H-3 beta
particles with max energy 18.6keV that would reach the plastic scintillator in a vacuum
setting as well as in an air medium. Scintillator thicknesses ranged from 10μm to
2500μm. The response of the system was determined by measuring the integrated counts
as a function of scintillator thickness. The results of these measurements showed the
expected positive linear correlation between scintillator thicknesses and integrated counts
for all the gamma sources while the slopes of the correlations of each gamma source was
a function of the source energy. The beta particle response showed an initial increase of
counts with scintillator thickness followed by a slight decrease. The MCNP simulation
confirmed an analytical calculation of the fraction of H-3 beta particles for a given air
concentration that would reach the scintillator. These results in conjunction with the
experimental findings were used to assess the potential of a plastic scintillator system
forming the basis of a tritium monitor for the detection of tritium in high-energy gamma
backgrounds for Canadian nuclear power workers. / UOIT
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OOSHDU.10155/177 |
| Date | 01 August 2011 |
| Creators | Kumar, Ashita |
| Contributors | Waker, Anthony |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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