Razvoj konvertera za učinkovitu detekciju termalnih neutrona

doctoral thesis

• Title (english): Development of converters for efficient detection of thermal neutrons
• Author: Robert Bernat
• Mentor: Šime Ukić (mentor)
• Mentor: Ivana Capan (mentor)
• Committee member: Tomislav Bolanča (predsjednik povjerenstva)
• Committee member: Vladimir Dananić (član povjerenstva)
• Committee member: Jasminka Popović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-06-11, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Applied Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy ; 53 - Physics ; 621 - Mechanical engineering. Nuclear technology. Machinery

Abstract

Cilj ovog doktorskog rada je razvoj konvertera za učinkovitu detekciju termalnih neutrona. Kao osnovni, aktivni materijal u poluvodičkom detektoru, koristi se širokopojasni 4H-SiC. S obzirom na to da se termalni neutroni ne mogu detektirati direktno s poluvodičkim, čvrstim, detektorom već preko nabijenih čestica koje nastaju interakcijom s drugim jezgrama, potreban je učinkovit konverter. Fokus istraživanja je na izotopima 6Li te 10B, koji u interakciji s termalnim neutronima emitiraju alfa-čestice (6Li(n,α)3H, 10B(n,α)7Li). U okviru istraživanja primijenjeno je nekoliko različitih metoda pripreme tankih filmova. Optimalna debljina tankog sloja filma određena je na temelju Monte Carlo simulacija, a očekivane vrijednosti su u granicama od 1 do 30 μm. Morfologija i struktura dobivenih filmova proučavane su mikroskopskim metodama. Učinkovitost dobivenih konvertera testirana je na nuklearnom reaktoru TRIGA Mark II Instituta Jožef Stefan u Ljubljani, Slovenija. Osim odziva detektora na termalne neutrone, obrađen je i odziv silicijeva karbida na druge izvore ionizirajućeg zračenja kao što su alfa-čestice i gama-zračenje.

Abstract (english)

This thesis deals with development of a converter for efficient detection of thermal neutrons. A wide gap 4H-SiC is used here as a basic, active material in the semiconductor detector. It is not possible to detect thermal neutrons directly with solid semiconductor detector, but through charged particles generated by interaction with other cores. Thus, an efficient converter is needed. The focus of the research is on the isotopes of 6Li and 10B, which interact with the thermal neutrons emitting alpha particles (6Li(n,α)3H, 10B(n,α)7Li). Within the scope of the research, a range of techniques of thin film preparation was used. Optimal thin film thickness was determined using Monte Carlo simulation. The expected values are within the range of 1 to 30 μm. The morphology and structure of the obtained films was studied by means of microscopy methods. Efficiency of the obtained converters was tested on the TRIGA Mark II nuclear reactor of the Jožef Stefan Institute in Ljubljana, Slovenia. In addition to the detector response to thermal neutrons, this thesis covers the response of silicon carbide to other sources of ionizing radiation such as alpha particles and gamma radiation as well.

• Keywords: detekcija neutrona; Monte Carlo simulacija; nuklearni reaktor; poluvodički detektor; silicijev karbid; tanki filmovi; termalni neutroni
• Keywords (english): neutron detection; Monte Carlo simulation; nuclear reactor; semiconductor detector; silicon carbide; thin films; thermal neutrons
• Language: croatian
• URN:NBN: urn:nbn:hr:149:298279
• Promotion: 2021
• Study programme: Title: Chemical Engineering and Applied Chemistry - Doctoral course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 102 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-06-02 13:40:41