Optimizing novel technologies for thermal neutron detection
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School of Science |
Master's thesis
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Date
2011
Department
Major/Subject
Sovellettu matematiikka
Mcode
Mat-2
Degree programme
Language
en
Pages
[16] + 96 + [9]
Series
Abstract
The field of neutron detection is a burgeoning area of research, spurred not only by advances in semiconductor fabrication, but also by the insu_cient capabilities of conventional techniques for novel applications of neutron radiation. For the past decades the trend in radiation detection has been to move in more and more applications towards semiconductor based detectors because they are cheap, compact and can provide detailed resolution. However, semiconductor neutron detectors have been plagued by low e_ciencies. One proposed way of overcoming this limitation is by manipulating the detector geometry on a microscale. In this thesis the methods to build such detectors are studied and a number of ways to optimize the possible designs are proposed. Geometrical optimization is based around precise Monte Carlo methods realized in the Geant4 framework. Neutron interaction is modeled in three dimensional microstructures to find the optimal structure for converting neutrons to measurable ionizing radiation. The used sophisticated simulation allows taking into account a number of factors discarded by previous authors. A prototype detector was built and experimental testing was completed to verify the predictions of the Monte Carlo modeling. Simulation results show that these microstructures have the capability to produce a manifold improvement in detection e_ciency over conventional semiconductor neutron detectors. Simulation results were also well in line with experimental results.Description
Supervisor
Ehtamo, HarriThesis advisor
Schulman, TomOrava, Risto
Keywords
thermal neutrons, termiska neutroner, neutron capture, neutronkapning, neutron cross section, gadolinium, gadolinium, bor, boron, borkabid, boron carbide, Geant4, geant4, 3n3, 3n3, halvledardetektor, semiconductor detector