Surface polishing of GSO scintillator using chemical process

Kurashige, K.; Kurata, Y.; Ishibashi, Hiroyuki; Susa, K.

doi:10.1109/23.682440

Cited by 44 publications

(15 citation statements)

References 4 publications

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“…Chemical etching is known to be helpful in improving the performance characteristics of scintillating crystals [22][23][24]. It gives a rough surface finish comparing with the mechanical polish [22] improving the light collection in the readout configuration when there is no optical contact between the sample and detector [24].…”

Section: Resultsmentioning

confidence: 99%

Effect of thermo-chemical treatments on the luminescence and scintillation properties of CaWO4

et al. 2008

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In this work, we investigated the influence of thermal annealing in different atmospheres on the luminescence and scintillation properties of CaWO 4 . Luminescence and luminescence excitation spectra were examined using VUV synchrotron radiation. Thermal treatment causes change of the defect subsystem of the crystal, resulting in the alteration of the spectral dependences. The most obvious effect is the relative change in the intensity of the defect emission band which is excited below the fundamental absorption edge 4.7 eV. Studies of the scintillation kinetics and light yield carried out over a temperature range 8-300 K showed that former does not change upon the treatment, in contrast to the intensity of scintillations. It is found that $50% increase of the scintillation response can be achieved for CaWO 4 samples annealed in hydrochloric acid.

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Section: Resultsmentioning

confidence: 99%

Effect of thermo-chemical treatments on the luminescence and scintillation properties of CaWO4

et al. 2008

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“…All crystals were 3 3 3 mm in size except for the 0.75 mol% samples, which were 3 3 2.5 mm , and had chemically etched surfaces [22]. Since crystal size affects the light collection efficiency and, therefore, the measured scintillation light output and energy resolution, we chose these small-size crystals to facilitate the comparative assessment of intrinsic scintillator characteristics.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of Lu$_{1.8}$Gd$_{0.2}$SiO$_{5}$:Ce (LGSO) for APD-Based PET Detector

Shimizu

Pépin

Bergeron

2010

IEEE Trans. Nucl. Sci.

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Since its discovery in 1993, LGSO has been seen as a promising scintillator for positron emission tomography (PET) imaging. Recently, new high lutetium content Lu 1 8 Gd 0 2 SiO 5 :Ce (LGSO-90%Lu) has been produced with Ce concentration varying from 0.025 to 0.75 mol% Ce, yielding decay times in the range of 34.2 to 44.8 ns. These scintillators could potentially be used as phoswich detectors in PET for improving spatial resolution. To validate this assumption, light output, energy resolution, temperature dependence, timing resolution, and pulse-shape discrimination performance were assessed. The light output of these LGSO scintillators is 3.5 to 4.8 times higher than BGO with avalanche photodiode readout [7.5 to 8 times with photomultiplier tube (PMT)] and increases with Ce concentration. The variation of light output for temperature ranging from 10 to 50 C is less than 18% with PMT readout. Energy resolution at 662 keV is about 11% (l0%) with avalanche photodiode (APD) (PMT) readout. Timing resolution with APD is 1.65 ns for all samples relative to a fast PMT-plastic detector. Pulse-shape discrimination of LGSO-90% Lu with 0.025 mol% Ce ( = 34 2 ns) and 0.75 mol% Ce ( = 44 8 ns) was successfully achieved in a phoswich assembly, making this new high lutetium content LGSO with adjustable decay time constants a strong candidate for a high-resolution depth-of-interaction detector intended for PET imaging.

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“…We use R as an abbreviation of a crystal element with rough surface and C with chemically etched surface. It is reported that the R and C have 411 nm and 382 nm roughness, 293 nm and 1045 nm waviness in their surface, respectively [12]. R has a property that it makes incident photons out to any other sides of coming side because rough surface diffuses the photons while C tends to transmit most of them to the same direction [13].…”

Section: B Parameters For Optimization Of the Crystal Blockmentioning

confidence: 99%

Improvement of the depth of interaction detector for PET on full energy pulse height uniformity

Kasahara

Murayama²,

Omura

et al. 2003

IEEE Trans. Nucl. Sci.

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As part of the next generation PET project, uniformity of full energy pulse height for all crystal elements was improved in the depth of interaction (DOI) detector constructed of three-dimensional crystal arrays.In our previous report, we found that the DOI detector constructed of four stages of a 2 2 Gd 2 SiO 5 : Ce (GSO) crystal array provides good crystal identification performance but poor uniformity of the energy pulse height distribution. The upper stage crystal elements which stay further from the photocathode of a PMT have a tendency to show lower energy pulse height. For example, the ratio of the full energy peak of the top stage crystal to the bottom stage one was about 0.3.We designed a new DOI detector improved in the uniformity. By optimizing crystal surface finishes, reflector configurations, and optical coupling between crystal elements, we got comparable energy pulse height from the upper stage crystals to the bottom stage crystals. Despite this change of detector conditions, good separation between each area corresponding to crystal elements is maintained on two-dimensional histograms obtained by Anger-type position calculation.The uniform full energy pulse height of every stage crystal allows a narrower dynamic range of the electrical circuits, and may give a great advantage in getting an accurate scatter correction. It also improves energy and timing resolution.Index Terms-Depth of interaction, nuclear medicine, positron emission tomography (PET), scintillation detector.

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Surface polishing of GSO scintillator using chemical process

Cited by 44 publications

References 4 publications

Effect of thermo-chemical treatments on the luminescence and scintillation properties of CaWO4

Effect of thermo-chemical treatments on the luminescence and scintillation properties of CaWO4

Characteristics of Lu$_{1.8}$Gd$_{0.2}$SiO$_{5}$:Ce (LGSO) for APD-Based PET Detector

Improvement of the depth of interaction detector for PET on full energy pulse height uniformity

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