Ternary cesium lithium iodide crystals grown by vertical Bridgman method for scintillation applications

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F24%3A00617547" target="_blank" >RIV/68378271:_____/24:00617547 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Ternary cesium lithium iodide crystals grown by vertical Bridgman method for scintillation applications

Popis výsledku v původním jazyce

In general, a scintillator is an energy converter of ionizing radiation (based on particles or high energy photons) into photons in the UV-VIS-IR region. Initially, the ionization leads to excitation of materials’ atoms and molecules into their excited states followed by the recombination of an electron-hole pair accompanied with photon emission and de-excitation back to their ground states. These emitted photons are detected by photodetectors, e.g., photomultiplier tube (PMT), and transformed into photoelectrons by multiplying the weak initial signal, which can be recorded with a software. The scintillator together with the photodetector form the scintillation detector. Among solid scintillators, organic as well as inorganic ones, nowadays, the most with practical applications, were developed. One of the most widely used material in radiation detection is thallium doped sodium iodide (NaI:Tl) discovered by Hofstadter in 1948. Even though it has very good spectrometric response to γ-ray and a light yield of 45 000 photons/MeV, the main disadvantages of a NaI:Tl detector are poor energy resolution (ca. 6-8 %) and slow scintillation response (ca. 300 ns). Thus, a new scintillation material meeting present and future challenges is sought-after. In application areas, such as nuclear power generation, nuclear decommissioning and decontamination, border security, nuclear proliferation and nuclear medicine, neutrons and their detectors play crucial role. Since 2008, the world has been facing the shortage of 3He, which has become extremely expensive, as the supply became limited. As 3He proportional counters represent the industry standard for neutron detection, there is high demand for a new scintillation material. For both neutron and X- and γ-ray detection, ternary alkali halides, such as Cs2Li3I5 (CLI) could represent an alternative material. CLI exhibits a light yield of ca. 40 000 to 55 000 photons/neutron, a primary decay time of just 250 ns for thermal neutron interactions and 500 ns for γ-rays, and, when doped with Eu, emission maxima peaking at ca. 450 nm. According to the CsI-LiI phase diagram reported by Sangster and Pelton, no ternary phase is present, however, the formation of a ternary CLI phase was already confirmed by Meyer and Gaebell in 1983. Nevertheless, the preparation of large CLI single crystals has not been published as of now. The goal of this work is to prepare single crystals of ternary CLI, confirm its phase purity and perform basic structural, physical, thermal, optical, luminescence, and scintillation characterizations. Further aim is to analyze the influence of doping of monovalent ions (e.g., Tl, In) in the matrix on its luminescence properties.

Název v anglickém jazyce

Ternary cesium lithium iodide crystals grown by vertical Bridgman method for scintillation applications

Popis výsledku anglicky

In general, a scintillator is an energy converter of ionizing radiation (based on particles or high energy photons) into photons in the UV-VIS-IR region. Initially, the ionization leads to excitation of materials’ atoms and molecules into their excited states followed by the recombination of an electron-hole pair accompanied with photon emission and de-excitation back to their ground states. These emitted photons are detected by photodetectors, e.g., photomultiplier tube (PMT), and transformed into photoelectrons by multiplying the weak initial signal, which can be recorded with a software. The scintillator together with the photodetector form the scintillation detector. Among solid scintillators, organic as well as inorganic ones, nowadays, the most with practical applications, were developed. One of the most widely used material in radiation detection is thallium doped sodium iodide (NaI:Tl) discovered by Hofstadter in 1948. Even though it has very good spectrometric response to γ-ray and a light yield of 45 000 photons/MeV, the main disadvantages of a NaI:Tl detector are poor energy resolution (ca. 6-8 %) and slow scintillation response (ca. 300 ns). Thus, a new scintillation material meeting present and future challenges is sought-after. In application areas, such as nuclear power generation, nuclear decommissioning and decontamination, border security, nuclear proliferation and nuclear medicine, neutrons and their detectors play crucial role. Since 2008, the world has been facing the shortage of 3He, which has become extremely expensive, as the supply became limited. As 3He proportional counters represent the industry standard for neutron detection, there is high demand for a new scintillation material. For both neutron and X- and γ-ray detection, ternary alkali halides, such as Cs2Li3I5 (CLI) could represent an alternative material. CLI exhibits a light yield of ca. 40 000 to 55 000 photons/neutron, a primary decay time of just 250 ns for thermal neutron interactions and 500 ns for γ-rays, and, when doped with Eu, emission maxima peaking at ca. 450 nm. According to the CsI-LiI phase diagram reported by Sangster and Pelton, no ternary phase is present, however, the formation of a ternary CLI phase was already confirmed by Meyer and Gaebell in 1983. Nevertheless, the preparation of large CLI single crystals has not been published as of now. The goal of this work is to prepare single crystals of ternary CLI, confirm its phase purity and perform basic structural, physical, thermal, optical, luminescence, and scintillation characterizations. Further aim is to analyze the influence of doping of monovalent ions (e.g., Tl, In) in the matrix on its luminescence properties.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10306 - Optics (including laser optics and quantum optics)

Projekt

<a href="/cs/project/EF16_019%2F0000760" target="_blank" >EF16_019/0000760: Fyzika pevných látek pro 21. století</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů