Razvoj metode protonima inducirane emisije gama-zračenja za analizu i trodimenzionalno profiliranje lakih elemenata

doctoral thesis

• Title (english): Development of the proton induced gamma-ray emission technique for the analysis and three-dimensional profiling of light elements
• Author: Ivana Zamboni
• Mentor: Ivančica Bogdanović Radović (mentor)
• Committee member: Matko Milin (predsjednik povjerenstva)
• Committee member: Ivančica Bogdanović-Radović (član povjerenstva)
• Committee member: Tamara Nikšić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2015-02-15, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics
• Universal decimal classification (UDC): 53 - Physics

Abstract

Protonima inducirana emisija gama-zračenja (PIGE) moćna je i nedestruktivna analitička metoda koja koristi međudjelovanje brzih (1-10 MeV) nabijenih čestica s jezgrama atoma u površinskim slojevima uzorka (0-50 μm), u svrhu određivanja sastava pomoću mjerenja karakterističnog gama-zračenja. U ovom radu izmjereni su diferencijalni udarni presjeci za emisiju gama-zračenja iz reakcija 19F(p,p'γ)19F (Eγ=110, 197, 1236 i 1349+1357 keV), 23Na(p,p'γ)23Na (Eγ=440 i 1636 keV), 23Na(p,α'γ)20Ne (Eγ=1634 keV), 24Mg(p,p'γ)24Mg (Eγ=1369 keV), 25Mg(p,p'γ)25Mg (Eγ=390, 585 i 975 keV), 27Al(p,p'γ)27Al (Eγ=844 i 1014 keV) i 27Al(p,α'γ) 24Mg (Eγ=1369 keV) za energije protona od 2 do 3 MeV-a s korakom od 15 keV-a. Pouzdani podaci za ovo energijsko područje nedostajali su u bazama podataka te su nova mjerenja bila neophodna za kvantitativnu PIGE analizu budući da se PIGE udarni presjeci ne mogu jednostavno teorijski opisati zbog prisustva mnogo uskih i jakih rezonanci. Dobiveni podaci uspoređeni su s prije izmjerenim udarnim presjecima, za druge kuteve detekcije i energije pobuđenja, te su uključeni u IBANDL i EXFOR baze podataka. Podrobnije je analizirana mogućnost dubinskog profiliranje magnezija s nanometarskom dubinskom razlučivošću korištenjem uočenih rezonaci na 2.01 i 2.41 MeV-a u 24Mg(p,p'γ)24Mg nuklearnoj reakciji. Rad uključuje i izvedbu eksperimentalnog postava za trodimenzionalno profiliranje korištenjem fokusiranog snopa protona na ionskoj mikroprobi, i to za detekciju gama-zračenja s germanijskim detektorom visoke čistoće (HPGe) i LaBr3:Ce anorganskim scintilacijskim detektorom nove generacije. Optimizirana metoda primijenjena je za dubinsko profiliranje 24Mg implantiranog u silicij te trodimenzionalno profiliranje 24Mg u mineralu sastavljenom od talka (Mg3Si4O10(OH)2) i pirita (FeS2). Također, iznesene su prednosti i mane razvijene i opisane metode u usporedbi s drugim metodama analize materijala pomoću ionskih snopova te ostalim metodama pogodnim za dubinsko profiliranje lakih elemenata.

Abstract (english)

Proton Induced Gamma-ray Emission (PIGE) is a powerful and non-destructive analytical technique that exploits the interactions of rapid (1-10 MeV) charged particles with atomic nuclei in sample surface layers (0-50 μm), in order to determine the composition by detection of characteristic prompt γ-rays. In this work differential cross sections for γ-ray emission from the reactions 19F(p,p'γ)19F (Eγ=110, 197, 1236 and 1349+1357 keV), 23Na(p,p'γ)23Na (Eγ=440 and 1636 keV), 23Na(p,α'γ)20Ne (Eγ=1634 keV), 24Mg(p,p'γ)24Mg (Eγ=1369 keV), 25Mg(p,p'γ)25Mg (Eγ=390, 585 and 975 keV), 27Al(p,p'γ)27Al (Eγ=844 and 1014 keV) and 27Al(p,α'γ) 24Mg (Eγ=1369 keV) were measured, for proton energies from 2 to 3 MeV with 15 keV energy step. Reliable data for differential cross sections for γ-ray emission in this energy region were scarce and new measurements were essential for the quantitative PIGE analysis. Due to the presence of many narrow and strong resonances, there is no common theoretical description of PIGE cross sections. Measured data were compared with the previously measured cross sections, at the different scattering angles and excitation energies, and have been uploaded to IBANDL and EXFOR databases. Furthermore, potential for depth profiling of magnesium with nanometre resolution using observed resonances at 2.01 and 2.41 MeV energy in 24Mg(p,p'γ)24Mg nuclear reaction was investigated. The work includes implementation of the experimental set-up for three-dimensional (3D) profiling with the use of focused proton beam at the ion microprobe and two different γ-ray detectors: high purity germanium (HPGe) and new generation of LaBr3:Ce inorganic scintillator detector. Optimized method was applied for depth profiling of 24Mg implanted in silicon and 3D profiling of 24Mg in mineral composed of talc (Mg3Si4O10(OH)2) and pyrite (FeS2). Advantages and disadvantages of the developed and presented technique were discussed in comparison with the other ion beam analysis (IBA) methods and supplementary techniques suitable for depth profiling of light elements.

• Keywords: PIGE; diferencijalni udarni presjek; magnezij; rezonanca; dubinsko profiliranje; ionska mikroproba; trodimenzionalno profiliranje; HPGe detektor; LaBr3:Ce scintilacijski detektor
• Keywords (english): PIGE; differential cross section; magnesium; resonance; depth profiling; 3D profiling; ion microprobe; HPGe detector; LaBr3:Ce scintillator detector
• Language: croatian
• URN:NBN: urn:nbn:hr:217:041684
• Study programme: Title: Physics; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika (doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika)
• Type of resource: Text
• Extent: 134 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-08-21 11:18:28