Thermal neutron imaging with CsBr storage phosphors

Luminescence and Scintillation Properties of LiF:W Single Crystal for Thermal-Neutron Detection

“…Taking into account the quantum efficiency of the PMT (R7600U-200; 42.09, 41.01, and 36.07% at 370, 400, and 440 nm, respectively) and the known light yield of GS20 (~6000 photons/neutron (15) ), the light yields of LiF:W and LiCaAlF 6 :Eu were estimated to be approximately 90 and 20000 photons/neutron, respectively. The light yield of LiF:W was found to be significantly lower than those of LiCaAlF 6 :Eu and GS20; however, the LiF single crystal is still an attractive host material for thermal-neutron detection because of the high 6 Li density, so it still remains a possibility that LiF-based materials may be used in practical applications if the light yield is somewhat improved. For further improvements, other possible luminescent centers such as defects or other dopants should be considered.…”

“…The conversion mechanisms vary depending on the phosphor types and applications. For example, storage phosphors (known as thermally stimulated luminescence, (2) optically stimulated luminescence, (3)(4)(5)(6) and radio-photoluminescence (7)(8)(9)(10)(11) ) are used to record information on radiation dose and distribution in 2-and 3-dimensional scales whereas scintillators immediately convert radiation to light, so they are advantageous for online measurements. (12) In recent years, such phosphor materials in particular are of considerable interest as an alternative to neutron detectors using 3 He gas, which is, in fact, suffering from a severely rapid decrease in supply but is still being relied on as the most common detection element used in thermal-neutron detectors.…”

“…(12) In recent years, such phosphor materials in particular are of considerable interest as an alternative to neutron detectors using 3 He gas, which is, in fact, suffering from a severely rapid decrease in supply but is still being relied on as the most common detection element used in thermal-neutron detectors. (13,14) In scintillation counters that consist of a solid thermal-neutron scintillator and a photodetector, for example, the scintillator can contain 6 Li elements so that they convert thermal neutrons into high-energy charged particles, and these charged particles excite luminescence centers in the scintillator material. Hence, thermal-neutron scintillators can emit luminescence in response to the incident thermal neutrons.…”

“…Hence, thermal-neutron scintillators can emit luminescence in response to the incident thermal neutrons. The main required characteristics are high light yield, fast decay time, adequate emission spectrum detectable using typical photodetectors, and high 6 Li density (or high interaction probabilities). The details of the required characteristics and properties of traditional materials were reviewed by van Eijk et al, (15) who comprehensively covered, for example, LiF/ZnS:Ag, LiI:Eu, Cs 2 LiYCl 6 :Ce, and GS20 (Ce-doped lithium silicate glass).…”

“…We describe the characteristics of a LiF:W (LiF doped with WO 3 ) single crystal as a thermal-neutron scintillator. The LiF single crystal is an attractive host material because of its high 6 Li density. According to the literature, , respectively.…”