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Bachelor's Thesis
Author of thesis: Josef Hynšt
Acad. year: 2025/2026
Supervisor: Ing. Břetislav Mikel, Ph.D.
Reviewer: Ing. Radek Helán, Ph.D.
This bachelor thesis focuses on the design, construction, and characterization of a fiber-optic scintillation measuring system developed for two-dimensional characterization of spatial profiles of gamma radiation beams from high-activity sources. The developed system successfully extends previous single-point measurements conducted at the Institute of Scientific Instruments of the CAS into an automated scanning apparatus. The primary advantage of the proposed solution is the separation of expensive evaluation electronics and the photomultiplier tube outside the irradiated area, thereby minimizing their radiation degradation. The measuring head utilizes an array of parallel sensors consisting of inorganic scintillation crystals and silica optical fibers. The sensor configuration and the linear stage step define a 16 x 16 pixel detection matrix covering a total area of 40 x 40 mm. Optical channel switching into a shared photomultiplier is handled by a mechanical fiber carousel, and the entire data acquisition process is fully automated using Python. Software data processing, including channel normalization, the application of a Savitzky-Golay filter, and bicubic interpolation, enabled spatial localization of point radiation sources with sub-pixel resolution. The system's capability to reliably resolve up to four independent point sources was also experimentally confirmed. The thesis concludes by outlining prospects for future development, particularly transitioning to silicon photomultipliers and utilizing thinner optical fibers to enhance spatial resolution.
ionizing radiation, gamma radiation, scintillation detector, LYSO(Ce), optical fiber, 2D scanning, automation, Python
Date of defence
17.06.2026
Result of the defence
Defended (thesis was successfully defended)
Grading
A
Process of defence
Po otázkách oponenta bylo dále diskutováno: - použitelné metody měření energie vysokoenergetických fotonů - využití scientilačních detektorů Student na otázky odpověděl.
Language of thesis
Czech
Faculty
Fakulta strojního inženýrství
Department
Institute of Physical Engineering
Study programme
Physical Engineering and Nanotechnology (B-FIN-P)
Composition of Committee
prof. Ing. Miroslav Kolíbal, Ph.D. (předseda) prof. RNDr. Tomáš Šikola, CSc. (místopředseda) prof. RNDr. Jiří Spousta, Ph.D. (člen) prof. RNDr. Petr Dub, CSc. (člen) prof. Ing. Jan Čechal, Ph.D. (člen) prof. Mgr. Miroslav Černý, Ph.D. (člen) doc. Mgr. Vlastimil Křápek, Ph.D. (člen) doc. Ing. Stanislav Průša, Ph.D. (člen) doc. Ing. Miroslav Bartošík, Ph.D. (člen) doc. Ing. Radek Kalousek, Ph.D. (člen) doc. Ing. Jakub Zlámal, Ph.D. (člen) prof. RNDr. Radim Chmelík, Ph.D. (člen)
Supervisor’s reportIng. Břetislav Mikel, Ph.D.
Grade proposed by supervisor: A
Reviewer’s reportIng. Radek Helán, Ph.D.
Grade proposed by reviewer: A
Responsibility: Mgr. et Mgr. Hana Odstrčilová