The neutron plays a central role in numerous fields of physics, a fact that entails a need for methods of measuring neutron energy spectra. In this project, a technique for neutron spectrometry through measurements of neutron-induced radioactivity in activation detectors was developed and tested. The developed technique involves irradiating element samples with neutrons, measuring activation products with a gamma spectrometer, and then performing a neutron spectrum unfolding procedure. The elements indium, iron, magnesium, aluminium, zinc, titanium, and copper were used as activation detectors and irradiated with neutrons from an americium-beryllium (AmBe) neutron source. Subsequent gamma spectrometry was performed with the UGGLA high-purity germanium detector setup at Uppsala University. The GRAVEL unfolding algorithm was implemented in MATLAB and used to unfold neutron spectra based on an initial spectrum guess. The unfolded neutron spectrum agrees well with the expected AmBe spectrum, though some difference between the spectra is attributed to neutron scattering in the irradiation environment. A possible ability to find approximate neutron spectra from inaccurate initial guesses is found, but additional work is needed to understand better how the initial guess affects the result for different neutron sources. Because activation detectors do not require electrical power when measuring neutrons, can be made sensitive to a wide range of neutron energies, and do not detect other types of radiation, future applications could find the developed neutron spectrometry method practical.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-524059 |
| Date | January 2024 |
| Creators | Arnqvist, Elias |
| Publisher | Uppsala universitet, Tillämpad kärnfysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | MATVET-F |
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