| 1. |
- Swiderski, L., et al.
(author)
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CsI:T1 Scintillation Pulse Shapes Measured with a SiPM Photodetector in a Liquid Nitrogen Cryostat
- 2016
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In: 2016 IEEE NUCLEAR SCIENCE SYMPOSIUM, MEDICAL IMAGING CONFERENCE AND ROOM-TEMPERATURE SEMICONDUCTOR DETECTOR WORKSHOP (NSS/MIC/RTSD). - : IEEE. - 9781509016426
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Conference paper (peer-reviewed)abstract
- A custom designed cryostat was constructed to measure the response of a CsI:T1 scintillator at temperatures close to the boiling point of liquid nitrogen (LN2). The scintillation light was collected by an HUV-HD SiPM from FBK with 6x6 mm(2) area and 25x25 mu m(2) cell pitch. The crystal size was 5x6x7 mm(3). All surfaces except the one facing the SiPM were covered with Teflon tape to enhance light collection by the photodetector. The performance of the experimental setup was verified at room temperature using analog electronics for signal processing. The crystal was mounted on a copper frame placed inside the LN2 cryostat. Since our goal was to measure the scintillation decay profiles, and the SiPM response at low temperatures becomes substantially slower than that observed at room temperature, the SiPM was mounted on a separate copper frame connected with the outer housing to keep it close to room temperature. The separation between the crystal surface and the SiPM was about 1.5 mm at room temperature, and it became smaller once the setup was cooled down to LN2 temperature, but even so the crystal and the photodetector were still separated. This approach allowed us to analyze scintillation pulse shapes of CsI:T1 at LN2 temperatures. An energy spectrum of 662 keV gamma-rays from a Cs-137 source was also recorded. The light yield of the CsI:T1 sample at LN2 temperature stands at about 6 % divided by 8 % of the value observed at room temperature.
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| 2. |
- Swiderski, L., et al.
(author)
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CsLTl scintillation pulse shapes measured with a SiPM photodeteetor in a liquid nitrogen cryostat
- 2017
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In: 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop, NSS/MIC/RTSD 2016. - : Institute of Electrical and Electronics Engineers (IEEE).
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Conference paper (peer-reviewed)abstract
- A custom designed cryostat was constructed to measure the response of a CsI:Tl scintillator at temperatures close to the boiling point of liquid nitrogen (LN 2 ). The scintillation light was collected by an HUV-HD SiPM from FBK with 6×6 mm 2 area and 25×25 μm 2 cell pitch. The crystal size was 5×6×7 mm 3 . All surfaces except the one facing the SiPM were covered with Teflon tape to enhance light collection by the photodetector. The performance of the experimental setup was verified at room temperature using analog electronics for signal processing. The crystal was mounted on a copper frame placed inside the LN 2 cryostat. Since our goal was to measure the scintillation decay profiles, and the SiPM response at low temperatures becomes substantially slower than that observed at room temperature, the SiPM was mounted on a separate copper frame connected with the outer housing to keep it close to room temperature. The separation between the crystal surface and the SiPM was about 1.5 mm at room temperature, and it became smaller once the setup was cooled down to LN 2 temperature, but even so the crystal and the photodetector were still separated. This approach allowed us to analyze scintillation pulse shapes of CsI:Tl at LN 2 temperatures. An energy spectrum of 662 keV γ-rays from a 137 Cs source was also recorded. The light yield of the CsI:Tl sample at LN 2 temperature stands at about 6 % ÷ 8 % of the value observed at room temperature.
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| 3. |
- Swiderski, L., et al.
(author)
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Scintillation response to gamma-rays measured at wide temperature range for Tl doped CsI with SiPM readout
- 2019
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In: Nuclear Instruments and Methods in Physics Research Section A. - : ELSEVIER SCIENCE BV. - 0168-9002 .- 1872-9576. ; 916, s. 32-36
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Journal article (peer-reviewed)abstract
- A custom design cryostat was constructed to study the temperature dependence of relative light yield and non-proportionality trends of scintillators between -182 degrees C and +152 degrees C. CsI:Tl crystal response to gamma-rays and X-rays was investigated between 14 keV and 662 keV. Scintillation light was detected by a SiPM device, which was installed on a copper frame separated from the crystal and the cooling rod to enable operating the device at room temperature. The scintillation efficiency of CsI:Tl is peaked at about room temperature. The light yield of CsI:Tl at temperature close to liquid nitrogen boiling point is reduced by a factor of 15 in comparison to room temperature conditions. The non-proportionality of CsI:Tl scintillation response is high at low temperatures and is getting more proportional with increasing temperature.
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| 4. |
- Swiderski, L., et al.
(author)
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Temperature Dependence of CsI:T1 Scintillation Pulse Shapes from-183 degrees C to+90 degrees C Measured with a SiPM Readout
- 2017
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In: 2017 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC). - : IEEE. - 9781538622827
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Conference paper (peer-reviewed)abstract
- A custom designed cryostat was constructed to measure the response of a CsI:T1 scintillator in temperature range from -183 degrees C up to +90 degrees C. The light readout was realized using a SiPM developed by FBK in near ultraviolet high density (NUV-HD) technology. The crystal and the SiPM were installed on separated copper frames. The crystal was cooled down by liquid nitrogen, while the SiPM was kept at temperature close to room temperature. A separation of 1 mm was kept between the crystal and the photodetector to ensure thermal isolation. The temperature of the crystal could be varied by heaters on the scintillator frame and was continuously monitored using a coil shaped resistance thermometer. The CsI:T1 scintillation decay profiles were recorded in the entire temperature range provided by the cryostat.
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| 5. |
- Swiderski, L., et al.
(author)
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Temperature Dependence of CsI:Tl Scintillation Pulse Shapes from -183°C to +90°C Measured with a SiPM Readout
- 2018
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In: 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2017 - Conference Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538622827
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Conference paper (peer-reviewed)abstract
- A custom designed cryostat was constructed to measure the response of a CsI:Tl scintillator in temperature range from - 183 ^{circ}\mathrm {C} up to +90 ^{circ}\mathrm {C}. The light readout was realized using a SiPM developed by FBK in near ultraviolet high density (NUV-HD) technology. The crystal and the SiPM were installed on separated copper frames. The crystal was cooled down by liquid nitrogen, while the SiPM was kept at temperature close to room temperature. A separation of 1 mm was kept between the crystal and the photodetector to ensure thermal isolation. The temperature of the crystal could be varied by heaters on the scintillator frame and was continuously monitored using a coil shaped resistance thermometer. The CsI:Tl scintillation decay profiles were recorded in the entire temperature range provided by the cryostat.
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| 6. |
- Swiderski, L., et al.
(author)
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Boron-10 loaded BC523A liquid scintillator for neutron detection in the border monitoring
- 2007
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In: 2007 IEEE Nuclear Science Symposium & Medical Imaging Conference. - : IEEE. - 1424409233 - 9781424409235 ; , s. 1389-1395
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Conference paper (peer-reviewed)abstract
- A BC523A liquid scintillator loaded with boron-10 was tested as a detector for both fast and thermal neutrons. Pulse shape discrimination (PSD) method based on a zero-crossing principle was applied to distinguish between neutron and gamma radiation. High quantum efficiency Photonis XP5500B photomultiplier was used to enhance light detection from the scintillator. This allowed a good registration of the energy spectrum of neutron capture events on boron-10, corresponding to about 60 keVee. The applied PSD method proved to be useful for n/γ discrimination. A good resolving power of the method was achieved even without gating on neutron capture events. A comparison with a standard BC501A liquid scintillator was done to evaluate thermal neutrons detection efficiency in BC523A.
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| 7. |
- Swiderski, L., et al.
(author)
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Boron-10 Loaded BC523A Liquid Scintillator for Neutron Detection in the Border Monitoring
- 2008
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In: IEEE Transactions on Nuclear Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 55:6, s. 3710-3716
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Journal article (peer-reviewed)abstract
- A BC523A liquid scintillator loaded with boron-10 was tested as a detector for both fast and thermal neutrons. A pulse shape discrimination (PSD) method based on a zero-crossing principle was applied to distinguish between neutron and gamma radiation. High quantum efficiency Photonis XP5500B photomultiplier was used to enhance light detection from the scintillator. This allowed a good registration of the energy spectrum of neutron capture events on boron-10, corresponding to about 60 keV gamma-rays. The applied PSD method proved to be useful for n/gamma discrimination. A good resolving power of the method was achieved even without gating on neutron capture events. A comparison with a standard BC501A liquid scintillator was done to evaluate thermal neutrons detection efficiency in BC523A.
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| 8. |
- Swiderski, L., et al.
(author)
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Further Study of Boron-10 Loaded Liquid Scintillators for Detection of Fast and Thermal Neutrons
- 2010
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In: IEEE Transactions on Nuclear Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 57:1, s. 375-380
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Journal article (peer-reviewed)abstract
- Boron-10 loaded liquid scintillators were studied in order to improve n/gamma separation. Pulse shape discrimination (PSD) was implemented by means of a zero-crossing (ZC) method to distinguish between gamma-rays and fast/slow neutrons. Significant progress was done for BC523A2 and EJ339A2 scintillators loaded with reduced amount of B-10 (2% and 2.5%, respectively), as compared to the results obtained earlier with BC523A loaded with 4.4% of B-10. The improvement was probably caused by the reduction of B-10 content, as indicated in the reported study. A B-10 loaded scintillator EJ309B5 based on non- flammable liquid was also studied, showing the best separation of thermal neutron capture events from fast neutrons, gamma-rays and noise.
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| 9. |
- Swiderski, L., et al.
(author)
-
Further study of Boron-10 loaded liquid scintillators for detection of fast and thermal neutrons
- 2008
-
Conference paper (peer-reviewed)abstract
- Boron-10 loaded liquid scintillators were studied in order to improve n/γ separation. Pulse shape discrimination (PSD) was done by means of a zero-crossing (ZC) method to distinguish between γ-rays and fast/slow neutrons. A significant progress was achieved for BC523A2 and EJ339A2 loaded with reduced amount of ,10B (2% and 2.5%, respectively), as compared to the results obtained earlier with BC523A loaded with 5% of 10B. The improvement was probably caused by the reduction of 10B content, as indicated in the latter study. A 10B loaded scintillator EJ309B5 based on a non-flammable liquid was also studied, showing the best separation of thermal neutron capture events from fast neutrons, γ-rays and noise.
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| 10. |
- Szczesniak, T., et al.
(author)
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A Time Resolution Study of a Continuous Crystal Detector for TOF PET
- 2010
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In: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 57:1, s. 40-47
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Journal article (peer-reviewed)abstract
- The majority of current Positron Emission Tomography (PET) systems are based on block-detectors consisting of many scintillating pixels read by a smaller number of photomultipliers (PMTs). An improvement of the time resolution, using a common light readout from a cluster of PMTs, was proposed by Kuhn et al., and tested by us earlier with LSO crystals. This, triggered an idea to design a new PET detector optimized for Time of Flight (TOF) systems, based on continuous crystals. In the present work, we report on optimization of timing with a 20 x 20 x 20 mm(3) LYSO crystal coupled to a 16-channel photomultiplier H8711-200MOD from Hamamatsu. First, measurements were performed of the transit time jitter, the number of photoelectrons and the time resolution using a small 10 x 10 x 5 mm(3) LSO crystal coupled to a H8711-200MOD PMT. Results were compared with data collected from fast timing photomultipliers like Photonis XP1020, XP3060, XP20D0 or Hamamatsu R9800. In the second part of the study, the time resolution measurements and the optimization of the system were made with a continuous LYSO crystal. The final results are discussed in terms of the measured photoelectron number and the requirements for the TOF-PET scanners.
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