arXiv subjects

Gul Rooh

Publications and source records attributed to Gul Rooh.

5 recordsLinked to original sources

arXiv2026

Preventing quart-NaI adhesion in Bridgman growth using ammonium iodide

Adhesion between NaI(Tl) single crystals and the walls of quartz ampoules remains a major limitation for Bridgman growth under sealed conditions, particularly for applications requiring ultra-radiopure scintillators for dark matter searches, where sealed handling is essential. In this study, ammonium iodide (NH4I) was used as an additive to generate HI in situ, thereby suppressing the NaOH-SiO2 reaction that forms adhesive sodium silicate phases. Small-diameter crystals (8 mm) were first grown to determine the NH4I concentration required to eliminate adhesion. The optimized condition was then applied to the growth of a large NaI(Tl) crystal. A crack-free and bubble-free NaI(Tl) crystal with dimensions of 3 inches in diameter by 3 inches in length was successfully grown. The crystal exhibited a light output of 59,000 photons/MeV, which is higher than that of the commercial NaI(Tl) crystals used as references in this study.

physics.ins-det↗

arXiv2017

The Characterization of new Eu2+ doped TlSr2I5 Scintillator Crystals

TlSr2I5: Eu2+ is a newly discovered scintillator and show promising scintillation properties for X- and γ-rays spectroscopy applications. Two zones vertical Bridgman technique is used for the growth of this scintillator. Luminescence properties of the grown crystals are measured under X-ray excitation at room temperature. Pure and Eu2+ doped crystals contained broad emission bands between 445-670 nm peaking at 528 nm and 430-600 nm peaking at 463 nm, respectively. Energy resolution, light yield and decay time profiles are studied under 662 keV γ-ray excitation using 137Cs radioactive source. Energy resolution of 4.2 % (FWHM) is obtained for 3 mol% Eu2+ doped crystal. For the same sample, light yield of 70,000 ph/MeV is also obtained. Three and two decay constants are observed for the pure and Eu2+ doped samples, respectively at room temperature. Effective Z-number and density are found to be 61 and 5.30 g/cm3, respectively.

physics.ins-det↗

arXiv2016

New Tl2LaBr5: Ce3+ Crystal Scintillator for γ-Rays Detection

In this study we present our preliminary report on the scintillation properties of new Ce-doped Tl2LaBr5 single crystal. Two zones vertical Bridgman technique is used for the growth of this compound. Pure and Ce-doped samples showed maximum emission peaks at 435 nm and 415 nm, respectively. Best light yield of 43,000+-4300 ph/MeV with 6.3% (FWHM) energy resolution is obtained for 5% Ce-doped sample under γ-ray excitation. Single exponential decay time constant of 25 ns is observed for 5% Ce doped sample. Effective Z-number is found to be 67, therefore efficient detection of X- and γ-ray will be possible. Preliminary results revealed that this compound will be an ideal candidate for the medical imaging techniques. Further investigations are under way for the determination of optimized conditions of this compound.

physics.ins-det↗

arXiv2016

Tl2LaCl5 (Ce3+): New Fast and Efficient Scintillator for X- and γ-ray detection

Scintillation properties of the new Tl2LaCl5: xCe3+ where x = 0, 0.5, 1 and 10 mole % (TLC: Ce3+) single crystals are presented. Two zones vertical Bridgman technique is used for the growth of this scintillation material. High Z-number (79) of this material offer excellent detection efficiency for X- and γ-rays. Grown samples are characterized under X- and γ-rays excitation in order to find the emission wavelength, energy resolution, light yield, and decay time. Emission spectra exhibit Ce3+ emission bands between 350 - 550 nm and peaking at 389 nm. The obtained energy resolution and light yield increases with high Ce-concentration. Energy resolution and light yield of 10%Ce-doped sample are found to be 6.9% (FWHM) and 51,000+-5000 ph/MeV, respectively at room temperature. For the grown samples, two exponential decay time constants are found. The measured decay time constants showed variation in their values with respect to Ce-concentrations in the host crystal. Fast decay time constant of 31 ns with 87% light emission is found for 10%Ce sample. Scintillation results suggested that TLC will be one of the promising next generation scintillator for the medical imaging techniques such as Positron Emission Tomography (PET).

cond-mat.mtrl-sci↗

arXiv2016

Scintillation Characterizations of Tl2LiLuCl6: Ce3+ Single Crystal

0.5%, 1%, 3% and 5% Ce-concentration single crystals of Tl2LiLuCl6 were grown from the melt using two zone vertical Bridgman technique. X-ray induced emission spectra showed Ce3+ emission between 370 nm and 540 nm wavelength range. Energy resolution, light yield and decay time of the grown samples were measured under γ-ray excitation at room temperature. Energy resolution of 5.6% (FWHM) with 27,000+-2700 light yield is found for 1%Ce doped sample. For the same dopant concentration, three decay time components are also observed. Variation of scintillation properties is observed as a function of dopant concentration in this material.This material will provide excellent detection efficiency for X- and γ-rays due to its high effective Z-number and density. It is expected that this scintillor will be a potential detector for the medical imaging techniques.

cond-mat.mtrl-sci↗