Characteristics of cesium iodide for use as a particle discriminator for high-energy cosmic rays

Crannell, C. J.; Kurz, R.; Viehmann, W.

doi:10.1016/0029-554x(74)90454-6

Cited by 21 publications

(9 citation statements)

References 9 publications

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“…For gamma-ray excitation at room temperature, the emission spectrum of CsI(TI) has been reported to have up to four emission bands, the most prevalent of which peaks at about 560 nm [5][6][7][8][9][10][11][12][13][14][15] . The emission spectrum of a scintillating crystal is of interest for two reasons: the peak emission wavelengths yield information about the nature of the decay modes that govern the scintillation process, and knowledge of the spectral distribution allows the estimation of the effective quantum efficiency when used with a given photodetector.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of CsI(Tl) gamma-ray excited scintillation characteristics

Valentine

Moses

Derenzo

et al. 1993

Nuclear Instruments and Methods in Physics Research Section A:

126

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The gamma-ray excited, temperature dependent scintillation characteristics of CsI(Tl) are reported over the temperature range of-100 to +50°C. The modified Bollinger-Thomas and shaped square wave methods were used to measure the rise and decay times. Emission spectra were measured using a monochromator and corrected for monochromator and photocathode spectral efficiencies. The shaped square wave method was also used to determine the scintillation yield as was a current mode method. The thermoluminescence emissions of CsI(TI) were measured using the same current mode method. At room temperature, CsI(T1) was found to have two primary decay components with decay time constants of T1=679±10 ns (63.7%) and T z = 3.34±0.14 Ws (36.1%), and to have emission bands at about 400 and 560 rim. The T1 luminescent state was observed to be populated by an exponential process with a resulting rise time constant of 19 .6±1 .9 ns at room temperature. An ultra-fast decay component with a < 0.5 ns decay time was found to emit about 0.2% (about 100 photons/MeV) of the total scintillation light. Except for the ultra-fast decay time, the rise and decay time constants were observed to increase exponentially with inverse temperature. At-80°C T1 and TZ were determined to be 2.22±0.33 ws and 18.0±2.59 ws, respectively, while the 400 rim emission band was not observed below-50°C. At +50°C the decay constants were found to be 628 ns (70.5%) and 2.63 ws (29.3%) and both emission bands were present. The scintillation yield of CsI(TI) was observed to be only slightly temperature dependent between-30 and +50°C, peaking at about-30°C (about 6% above the room temperature yield) and monotonically decreasing above and below this temperature. Four different commercially available CsI(TI) crystals were used. Minimal variations in the measured scintillation characteristics were observed among these four crystals. Thermoluminescence emissions were observed to have peak yields at-90,-65,-40, +20, and possibly-55°C. The relative magnitudes and number of thermolummescence peaks were found to vary from crystal to crystal.

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Section: Introductionmentioning

confidence: 99%

Temperature dependence of CsI(Tl) gamma-ray excited scintillation characteristics

Valentine

Moses

Derenzo

et al. 1993

Nuclear Instruments and Methods in Physics Research Section A:

126

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“…The larger the energy resolution, the worse the scintillation performance of the crystal. The broadening of spectral curves was due to the H 2 O molecule adsorption caused by the Na diffusion away from the crystal, which left behind “dead “regions with an activator (Na) concentration below the lowest limit for scintillation (0.01%) [ 14 ].…”

Section: Discussionmentioning

confidence: 99%

Effect of H2O Molecule Adsorption on the Electronic Structure and Optical Properties of the CsI(Na) Crystal

et al. 2021

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We investigated H2O molecule adsorption that had an effect on the luminescence properties of the CsI(Na) crystal using experiments and first-principle calculations. We measured the emission spectra of the CsI(Na) crystal at different exposure times under gamma ray excitation. The experimental results showed that the energy resolution of the CsI(Na) crystal was worse when the crystal surface adsorbed more H2O molecules, and the crystal surface deliquescence decreased the luminescence efficiency of the CsI(Na) crystal. We studied the band structure, density of states, and optical properties changes caused by H2O molecule adsorption on the CsI(Na) (010) surface. The generalized gradient approximation (GGA) was used to describe the exchange and correlation potential between the electrons. Our calculation results showed that the band gap width of the CsI(Na) (010) surface decreased after adsorbing H2O molecules, while three new peaks appeared in the valence band, and the absorption coefficient decreased from 90,000 cm−1 to 65,000 cm−1, and the reflection coefficient decreased from 0.195 to 0.105. Further, the absorption coefficient was reduced by at least 25% because of H2O molecule adsorption, which led to the luminescence degradation of the CsI(Na) crystal.

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“…Furthermore, the nanoparticles of NaI are more hygroscopic in the air than other alkali halides. An anti-moisture process after the deposition process of CsI:Na film is necessary because the hygroscopic nanoparticles remarkably decrease the luminescence scintillation and generate cracks in the cylindrical structure [9,12,[22][23][24][25]. In previous studies, the protective SiO 2 , Al, and parylene-N layers subsequently deposited on the CsI or CsI:Na film in the same vacuum chamber was investigated, respectively [14][15][16][17]19].…”

Section: Introductionmentioning

confidence: 99%

Luminescence of CsI and CsI:Na Films under LED and X-ray Excitation

Hsu

2019

Coatings

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In this study, we investigated the luminous properties of undoped cesium iodide (CsI) and Na-doped CsI (CsI:Na) films deposited by thermal vacuum evaporation and treated with different substrate temperatures, post-annealing temperatures, and deposition rates. The quality of the deposited films was evaluated by their XRD pattern, SEM cross-section/surface morphologies and UV/X-ray luminescence, the spectra of which were used to derive the luminescence mechanism of the deposited films. The 310 nm luminescence demonstrates that the exciting light arises from the electron–hole recombination through the self-trapped exciton (STE) process, which is characteristic of the host polycrystalline CsI. The broad-band luminescence from ~400 to 450 nm demonstrates the other electron–hole recombination between the new energy states created by doping Na in the forbidden gap of CsI. When we deposited higher quality films at a substrate temperature of 200 °C, the undoped CsI films showed preferred crystal orientation at (200), and the CsI:Na films co-evaporated by 1 wt.% NaI at (310) and had the highest UV/X-ray luminescence.

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Characteristics of cesium iodide for use as a particle discriminator for high-energy cosmic rays

Cited by 21 publications

References 9 publications

Temperature dependence of CsI(Tl) gamma-ray excited scintillation characteristics

Temperature dependence of CsI(Tl) gamma-ray excited scintillation characteristics

Effect of H2O Molecule Adsorption on the Electronic Structure and Optical Properties of the CsI(Na) Crystal

Luminescence of CsI and CsI:Na Films under LED and X-ray Excitation

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