Scintillation properties of strontium iodide doped with europium for high-energy astrophysical detectors: nonproportionality as a function of temperature and at high gamma-ray energies

Perea, Rose; Parsons, A.; Groza, Michael; Caudel, David; Nowicki, S.; Bürger, A.; Stassun, Keivan G.; Peterson, Todd E.

doi:10.1117/1.jatis.1.1.016002

Cited by 4 publications

(2 citation statements)

References 26 publications

(50 reference statements)

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“…A number of new gamma-ray scintillation materials look promising and have been proposed for space missions [1] [2] [3] [4], while silicon photomultiplier (SiPM) readout technologies are also quickly replacing traditional photomultiplier tubes (PMTs) in instrument concepts [5] [6] [7]. The goal of the Strontium Iodide Radiation Instrument (SIRI) mission is to study the performance of new SiPM technology and a new scintillation material, europium-doped strontium iodide (SrI 2 :Eu), for space-based gamma-ray spectrometry.…”

Section: Introductionmentioning

confidence: 99%

Strontium Iodide Radiation Instrument (SIRI) – Early On-Orbit Results

Mitchell

Phlips

Grove

et al. 2019

2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

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The Strontium Iodide Radiation Instrument (SIRI) is a single detector, gamma-ray spectrometer designed to space-qualify the new scintillation detector material europiumdoped strontium iodide (SrI 2 :Eu) and new silicon photomultiplier (SiPM) technology. SIRI covers the energy range from .04 -8 MeV and was launched into 600 km sunsynchronous orbit on Dec 3, 2018 onboard STPSat-5 with a one-year mission to investigate the detector's response to onorbit background radiation. The detector has an active volume of 11.6 cm 3 and a photo fraction efficiency of 50% at 662 keV for gamma-rays parallel to the long axis of the crystal. Its spectroscopic resolution of 4.3% was measured by the fullwidth-half-maximum of the characteristic Cs-137 gamma-ray line at 662 keV. Measured background rates external to the trapped particle regions are 40-50 counts per second for energies greater than 40 keV and are largely the result of short-and long-term activation products generated by transits of the South Atlantic Anomaly (SAA) and the continual cosmic-ray bombardment. Rate maps determined from energy cuts of the collected spectral data show the expected contributions from the various trapped particle regions. Early spectra acquired by the instrument show the presence of at least 10 characteristic gamma-ray lines and a beta continuum generated by activation products within the detector and surrounding materials. As of April 2019, the instrument has acquired over 1000 hours of data and is expected to continue operations until the space vehicle is decommissioned in Dec. 2019. Results indicate SrI 2 :Eu provides a feasible alternative to traditional sodium iodide and cesium iodide scintillators, especially for missions where a factor-of-two improvement in energy resolution would represent a significant difference in scientific return. To the best of our knowledge, SIRI is the first on-orbit use of SrI 2 :Eu scintillator with SiPM readouts.

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Section: Introductionmentioning

confidence: 99%

Strontium Iodide Radiation Instrument (SIRI) – Early On-Orbit Results

Mitchell

Phlips

Grove

et al. 2019

2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

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“…However, owing to recent progress of crystal growth technology, dramatically improved scintillation properties (eg. scintillation light yield, energy resolution and decay time) have been discovered in Eu-doped SrI 2 crystals [22][23][24][25][26][27][28][29][30][31][32][33]. Eu-doped SrI 2 showed high light yield of 120000 ph/MeV (maximum value was reported in [25]), typically 3% energy resolution at 662 keV (the best value of 2.6% was achieved in [28]), and typically decay time of 1-2 s depending on the Eu concentration.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of nondoped and Eu-doped SrI2 scintillator

et al. 2016

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Optical and scintillation properties of nondoped and Eu 3% doped SrI 2 crystals grown by the Vertical Bridgman method were investigated. Eu-doped crystal showed an intense single band emission at 430 nm due to the Eu 2+ 5d-4f transitions in both photoluminescence and scintillation while the nondoped crystal had a complex spectral shape. The latter emission consists of mainly four bands: 360 nm, 540 nm, 410 nm and 430 nm. The origins of 360 nm and 540 nm were self-trapped exciton and unexpected impurity, respectively. The origins of 410 and 430 nm lines were ascribed to F center in different I sites. Under 137 Cs -ray irradiations, both crystals showed a clear photoabsorption peak. The scintillation light yields of the nondoped and Eu-doped SrI 2 resulted 33000 ph/MeV and 82000 ph/MeV, respectively. The energy resolution at 662 keV of Eu-doped was 4% while that of the non-doped SrI 2 was 8%.

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Radiation damage of strontium iodide crystals due to irradiation by 137Cs gamma rays: A novel approach to altering nonproportionality

Caudel

McCurdy

Fleetwood

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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Strontium iodide doped with europium (SrI 2 :Eu 2+) is a new scintillator being developed for use in high-energy astrophysical detectors with excellent energy resolution. Nonproportionality is the primary limiting factor to improving its energy resolution, although the physics of nonproportionality is not yet fully understood. In the past few years, co-dopants have been used to alter nonproportionality. By irradiating a SrI 2 :Eu 2+ sample with a 2,255 Ci 137 Cs source, we explore both the crystal's potential for space-based applications in a radiation environment and this new method of altering nonproportionality. At ~6,200 Gy irradiation, a drop of 7.8% at 700 nm and a drop of 14.1% at 450 nm were seen in the transmission spectrum. Nonproportionality was also reduced after irradiation, shifting from 87% to 101% of the theoretical light yield at 32.1 keV, while the 4.7 keV peak decreased 40% closer to its theoretical value. We propose a novel method of altering the nonproportionality of scintillators, using radiation-induced F-centers in place of co-dopants.

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Scintillation properties of strontium iodide doped with europium for high-energy astrophysical detectors: nonproportionality as a function of temperature and at high gamma-ray energies

Cited by 4 publications

References 26 publications

Strontium Iodide Radiation Instrument (SIRI) – Early On-Orbit Results

Strontium Iodide Radiation Instrument (SIRI) – Early On-Orbit Results

Comparative study of nondoped and Eu-doped SrI2 scintillator

Radiation damage of strontium iodide crystals due to irradiation by 137Cs gamma rays: A novel approach to altering nonproportionality

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