9 research outputs found
Temperature Dependence of CsI:Tl Scintillation Pulse Shapes from -183°C to +90°C Measured with a SiPM Readout
No full textA custom designed cryostat was constructed to
measure the response of a CsI:Tl scintillator in temperature
range from -183°C up to +90°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
CsI:Tl scintillation pulse shapes measured with a SiPM photodetector in a liquid nitrogen cryostat
No full textA custom designed cryostat was constructed to measure the response of a CsI:Tl 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 6×6 mm2 area and 25×25 μm2 cell pitch. The crystal size was 5×6×7 mm3. 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:Tl at LN2 temperatures. An energy spectrum of 662 keV γ-rays from a 137Cs source was also recorded. The light yield of the CsI:Tl sample at LN2 temperature stands at about 6 % ÷ 8 % of the value observed at room temperature
Scintillation response to gamma-rays measured at wide temperature range for Tl doped CsI with SiPM readout
No full textA custom design cryostat was constructed to study the temperature dependence of relative light yield and non-proportionality trends of scintillators between −182 °C and +152 °C. CsI:Tl crystal response to
γ-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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Direct comparison of PEN and TPB wavelength shifters in a liquid argon detector
Get PDFA large number of particle detectors employ liquid argon as their target material owing to its high scintillation yield and its ability to drift ionization charge over large distances. Scintillation light from argon is peaked at 128 nm and a wavelength shifter is required for its efficient detection. In this work, we directly compare the light yield achieved in two identical liquid argon chambers, one of which is equipped with polyethylene naphthalate (PEN) and the other with tetraphenyl butadiene (TPB) wavelength shifter. Both chambers are lined with enhanced specular reflectors and instrumented with SiPMs with a coverage fraction of approximately 1%, which represents a geometry comparable to the future large scale detectors. We measured the light yield of the PEN chamber to be 39.40.4(stat)1.9(syst)% of the yield of the TPB chamber. Using a Monte Carlo simulation this result is used to extract the wavelength shifting efficiency of PEN relative to TPB equal to 47.25.7%. This result paves the way for the use of easily available PEN foils as a wavelength shifter, which can substantially simplify the construction of future liquid argon detectors
Cryogenic setup for the characterization of wavelength-shifting materials for noble element radiation detectors
Get PDFIn the present work, we describe a cryogenic setup for studies of
wavelength-shifting materials for optimised light collection in noble element
radiation detectors, and discuss the commissioning results. This SiPM-based
setup uses alpha induced scintillation in gaseous argon as the vacuum
ultraviolet light source with the goal of characterising materials, such as
polyethylene naphthalate (PEN) and tetraphenyl butadiene (TPB), in terms of
their wavelength-shifting efficiency. Further extensions of the system are
currently being studied. The foreseen upgrades are expected to allow the study
of GEM-like structures potentially interesting for rare-event searches. The
design of the setup will be addressed along with the first results.Comment: LIDINE 2023, 7 pages, 4 figures, 1 tabl
CsI:T1 Scintillation Pulse Shapes Measured with a SiPM Photodetector in a Liquid Nitrogen Cryostat
No full textA 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.</p
Temperature Dependence of CsI:T1 Scintillation Pulse Shapes from-183 degrees C to+90 degrees C Measured with a SiPM Readout
No full textA 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.</p
Development of very-thick transparent GEMs with wavelength-shifting capability for noble element TPCs
Get PDFA new concept for the simultaneous detection of primary and secondary scintillation in time projection chambers is proposed. Its core element is a type of very-thick GEM structure supplied with transparent electrodes and machined from a polyethylene naphthalate plate, a natural wavelength shifter. Such a device has good prospects for scalability and, by virtue of its genuine optical properties, it can improve on the light collection efficiency, energy threshold and resolution of conventional micropattern gas detectors. This, together with the intrinsic radiopurity of its constituting elements, offers advantages for noble gas and liquid based time projection chambers, used for dark matter searches and neutrino experiments. Production, optical and electrical characterization, and first measurements performed with the new device are reportedThis project was funded by the National Science Centre, Poland (Grant No. 2019/03/X/ST2/01560). The NCAC PAS team acknowledges support from the International Research Agenda Programme AstroCeNT (MAB/2018/7) funded by the Foundation for Polish Science from the European Regional Development Fund (ERDF). DGD acknowledges Ramon y Cajal program (Spain) under contract number RYC-2015-18820. AstroCeNT and TUM cooperation is supported from the EU’s Horizon 2020 research and innovation programme under grant agreement No 962480 (DarkWave project)S
FAT-GEMs: (Field Assisted) Transparent Gaseous-Electroluminescence Multipliers
Get PDFThe idea of implementing electroluminescence-based amplification through
transparent multi-hole structures (FAT-GEMs) has been entertained for some
time. Arguably, for such a technology to be attractive it should perform at
least at a level comparable to conventional alternatives based on wires or
meshes. We present now a detailed calorimetric study carried out for 5.9~keV
X-rays in xenon, for pressures ranging from 2 to 10~bar, resorting to different
geometries, production and post-processing techniques. At a reference voltage
5~times above the electroluminescence threshold (~kV/cm/bar),
the number of photoelectrons measured for the best structure was found to be
just 18\%~below that obtained for a double-mesh with the same thickness and at
the same distance. The energy resolution stayed within 10\% (relative) of the
double-mesh value.
An innovative characteristic of the structure is that vacuum ultraviolet
(VUV) transparency of the polymethyl methacrylate (PMMA) substrate was
achieved, effectively, through tetraphenylbutadiene (TPB) coating of the
electroluminescence channels combined with indium tin oxide (ITO) coating of
the electrodes. This resulted in a -increased optical yield
(compared to the bare structure), that was found to be in good agreement with
simulations if assuming a TPB wavelength-shifting-efficiency at the level of
WLSE=0.74-1.28, compatible with expected values. This result, combined with the
stability demonstrated for the TPB coating under electric field (over 20~h of
continuous operation), shows great potential to revolutionize
electroluminescence-based instrumentation
