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C.a.n. Conde - One of the best experts on this subject based on the ideXlab platform.
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Quenched and non-quenched Ar-Xe Penning mixtures as detection media for a Gridded-Microstrip Gas Chamber X-ray detector
2008 IEEE Nuclear Science Symposium Conference Record, 2008Co-Authors: Liliana P.m.m. Carita, C.a.n. Conde, F.p. SantosAbstract:The performance of quenched and non-quenched argon-xenon Penning mixtures in a Gridded-Microstrip Gas Chamber is studied for 5.9keV X-rays. The best energy resolution obtained was 12.7% for the 90%Ar-10%Xe mixtures. Charge multiplication gains one order of magnitude higher than in pure xenon were obtained for 95%Ar-5%Xe. With the addition of the quenching agent (methane), although the Gas gain at the same anode voltage decreases, a better energy resolution of 12.3% is achieved for the 85.5%Ar-5%Xe-9.5%CH4 mixture.
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The Gridded-Microstrip Gas Chamber as a High Energy Resolution Gaseous X-Ray Detector
IEEE Transactions on Nuclear Science, 2007Co-Authors: Liliana P.m.m. Carita, S.j.c. Do Carmo, F.p. Santos, C.a.n. CondeAbstract:A design for a Gaseous radiation detector based on charge multiplication is described and its performance assessed. The device uses a microstructure which has an anode surrounded by another close-lying second anode, playing the role of a grid at a potential between anode and cathode that allows a more accurate definition of the multiplication volume. The main characteristics of this gridded microstrip Gas Chamber (G-MSGC) detector are described. The best energy resolutions for 5.9 keV X-rays obtained were 13.4% for Xe and 12.6% for the P10 mixture.
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The Gas proportional scintillation counter/microstrip Gas Chamber hybrid detector
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2003Co-Authors: D.s.a.p. Freitas, J.f.c.a. Veloso, J.m.f. Dos Santos, C. M. B. Monteiro, C.a.n. CondeAbstract:The Gas proportional scintillation counter/microstrip Gas Chamber (GPSC/MSGC) hybrid detector for X-ray spectrometry is described. The detector uses a CsI-coated microstrip plate placed in direct contact with the Gas-filling as the photosensor readout for the GPSC scintillation substituting for the photomultiplier tube (PMT). Usable photosensor maximum gain is limited by optical positive feedback due to the additional scintillation produced in the electron avalanche process at the MSP anodes, in the absence of quenching. A low-photoelectron collection efficiency is achieved in the Gas atmosphere, resulting in a scintillation conversion efficiency that is about a factor of 5 lower than that achieved with PMT-based GPSCs. However, energy resolutions of 11% for 5.9 keV X-rays are achieved with this detector.
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Performance characteristics of a Gas proportional scintillation counter coupled to a microstrip Gas Chamber photosensor
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1999Co-Authors: J.f.c.a. Veloso, J.m.f. Dos Santos, C.a.n. CondeAbstract:A P10-filled microstrip Gas Chamber (MSGC) is used to replace the conventional photomultiplier tube (PMT) as the photosensor for a Gas proportional scintillation counter (GPSC). The vacuum ultra-violet (VUV) scintillation light produced in the xenon-filled GPSC is transmitted through a 1 mm thick high-purity quartz window to the MSGC where it is converted to photoelectrons by a CsI photocathode deposited directly onto the surface of a microstrip plate (MSP). These photoelectrons are afterwards multiplied near the microstrip plate anodes with a charge gain of about 103. The energy resolution achieved for 5.9 keV X-rays is 11.5% which, while not yet as good as the 8% figure for standard GPSC (instrumented with a PMT), is already better than the energy resolution obtained for standard proportional counters. Experimental results are presented and discussed. With this design a compact GPSC is obtained which has the further advantage of being much less sensitive to magnetic fields than PMT-based GPSCs. ( 1999 Elsevier Science B.V. All rights reserved.
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A microstrip Gas Chamber as a VUV photosensor for a xenon Gas proportional scintillation counter
IEEE Transactions on Nuclear Science, 1996Co-Authors: J.f.c.a. Veloso, Jose Lopes, J.m.f. Dos Santos, C.a.n. CondeAbstract:The characteristics of a one-atmosphere xenon Gas proportional scintillation counter (GPSC) instrumented with a novel photosensor are reported. A microstrip Gas Chamber (MSGC) with a CsI photocathode deposited directly onto its electrode surface is used in place of the standard photomultiplier tube assembly to record the scintillation light from xenon. The microstrip electrodes also function as the GPSC second scintillation grid. The combination results in a simple and compact device that demonstrates the linear response characteristics of the scintillation process in xenon.
Hideki Tsuge - One of the best experts on this subject based on the ideXlab platform.
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bubble formation at a nozzle submerged in viscous liquids having yield stress
Chemical Engineering Science, 2001Co-Authors: Koichi Terasaka, Hideki TsugeAbstract:Abstract The effects of operating conditions on bubble volume formed from a nozzle submerged in some viscous media with yield stress were experimentally investigated. Pressure fluctuations in the Gas Chamber accompanied by bubble formation as well as bubble growth curves were measured. By analysis of the time course of pressure change in the Gas Chamber, the dependency of the Gas flow rate into the Gas Chamber and the Chamber volume on the polytropic coefficient of Gas in the Gas Chamber was discussed. To simulate the bubble formation at a single nozzle in a viscous medium having yield stress, the non-spherical bubble formation model was proposed. The calculated bubble volumes agreed relatively well with the experimental ones.
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Bubble formation at a single orifice in non-newtonian liquids
Chemical Engineering Science, 1991Co-Authors: Koichi Terasaka, Hideki TsugeAbstract:Abstract The effects of various factors on the volumes and shapes of bubbles formed at a single orifice submerged in non-Newtonian liquids, such as physical properties of liquids, Gas Chamber volume, orifice diameter and Gas flow rate were studied. To clarify the bubble formation mechanism, the bubble volume, bubble shape and Gas Chamber pressure during the bubble growth were measured simultaneously. A revised non-spherical bubble formation model was proposed to describe the bubble formation mechanism in non-Newtonian liquids. The bubble volume, bubble shape and pressure change in the Gas Chamber calculated by this model agreed well with the experimental results over a wide range of rheological characteristics of liquids.
M. Salomon - One of the best experts on this subject based on the ideXlab platform.
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Test beam results of a low-pressure micro-strip Gas Chamber with a secondary-electron emitter
IEEE Transactions on Nuclear Science, 1995Co-Authors: S. Kwan, D.f. Anderson, J. Zimmerman, C. Sbarra, M. SalomonAbstract:We present recent results, from a beam test, on the angular dependence of the efficiency and the distribution of the signals on the anode strips of a low-pressure micro-strip Gas Chamber with a thick CsI layer as a secondary-electron emitter. New results of CVD diamond films as secondary-electron emitters are discussed. >
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A low-pressure, micro-strip Gas Chamber operated with secondary-electron emission
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 1994Co-Authors: D.f. Anderson, S. Kwan, M. SalomonAbstract:Abstract The operation of a low-pressure micro-strip Gas Chamber with a thick CsI secondary-electron emitting surface as the source of primary ionization is presented. Fast signals are produced and improvements in gain and timing resolutions of over an order of magnitude, compared to atmospheric devices, are achieved with reduced sensitivity to discharges. Such devices should have little or no angular dependence in their position and timing resolution, or on their efficiency.
Toru Tanimori - One of the best experts on this subject based on the ideXlab platform.
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Observation of Neutron-Induced Signals Using Two-Dimensional Micro-Pixel Gas Chamber
IEEE Transactions on Nuclear Science, 2009Co-Authors: K. Toh, Atsuhiko Ochi, H. Yamagishi, K. Sakasai, Takuma Nakamura, Kazuhiko Soyama, Toru TanimoriAbstract:A Gas-based neutron detection system which reads out individual channels with a micro-pixel detector element was constructed, and preliminary neutron irradiation tests were conducted. The detection system consisted of a micro-pixel detector element, a Gas Chamber that had feedthroughs for lines of 541 channels, amplifier-shaper-discriminator boards, position encoders with field programmable gate arrays, and a device capable of fast data acquisition. The micro-pixel detector element pulses had a short duration, the full width at half maximum of the pulse being 160 ns. Its Gas gain was about 50 with an anode-cathode voltage of 560 V and a Gas pressure of 0.5 MPa (0.45 MPa for He and 0.05 MPa for CF4). Signal pulse peaks of neutrons could be identified. The neutron detection system could easily distinguish neutron signals from other signals arising from electronic noise, gamma events, etc. The Gas gain of the micro-pixel detector element did not change for 240 min in our irradiation test.
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Observation of neutron-induced signals using two-dimensional micro-pixel Gas Chamber
2008 IEEE Nuclear Science Symposium Conference Record, 2008Co-Authors: K. Toh, Atsuhiko Ochi, H. Yamagishi, K. Sakasai, Takuma Nakamura, Kazuhiko Soyama, Toru TanimoriAbstract:A Gas-based neutron detection system with individual readout method and comprising a micro-pixel detector head was constructed, and preliminary experiments were conducted under neutrons irradiation. The detection system also consisted of a micro-pixel detector head, a Gas Chamber that had feedthrough lines of 541 channels, amplifier-shaper-discriminator boards, position encoders with field programmable gate arrays, and a device capable of fast data acquisition. The micro-pixel detector head exhibited a fast response time, and the full width at half maximum of the response time was 160 ns. Its Gas gain was about 50 at an anode-cathode voltage of 560 V and a Gas pressure of 0.5 MPa (0.45 MPa for He and 0.05 MPa for CF 4 ). Signal pulse peaks of neutrons could be identified and their output voltages at an anode and a cathode were 2.4 and 5.3 mV, respectively; on the other hand, the output voltage of all the anodes was 105 mV. The neutron detection system could easily distinguish neutron signals from the background noise, and the Gas gain of the micro-pixel detector head did not changed.
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Use of a MicroStrip Gas Chamber conductive capillary plate for time-resolved X-ray area detection
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: Atsuhiko Ochi, Yuji Nishi, Toru Tanimori, Tsutomu Nagayoshi, Hidehiro Uekusa, Yuji Ohashi, Yasuro Nishi, Hidenori ToyokawaAbstract:Abstract The stable operation of MicroStrip Gas Chamber (MSGC) was successfully performed using glass capillary plate as an intermediate Gas multiplier. Detection area of 95 mm2 was available and fine position resolution of 90 μm using digital readout was attained. A charge-up problem of capillary plate under intense radiation source was perfectly removed by surface conductivity inside of capillaries. The quantitative measurements using MSGC is now available in X-ray imaging. This paper also presents novel applications of X-ray diffraction studies and their preliminary results using an MSGC. Rapid measurements for X-ray crystallography of the order of a few tens of seconds were attained successfully.
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Performance of a micro-strip Gas Chamber in solution X-ray scattering
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: Hidenori Toyokawa, Yuji Nishi, Atsuhiko Ochi, Tetsuro Fujisawa, Youji Inoko, Tsutomu Nagayoshi, Yukihiro Nishikawa, Masayo Suzuki, Toru TanimoriAbstract:Abstract The performance of a Micro-Strip Gas Chamber in solution X-ray scattering was studied at the RIKEN structural biology beamline I of the SPring-8 facility. The practical dynamic range was confirmed to be ∼1,000,000 : 1 by measuring S −4 decay from a polystyrene latex solution. Steep troughs of scattering profile from an apoferritin solution were clearly obtained without smearing. An unfolding process of a pH jump of cytochrome c was measured. A time resolution of 500 μs was achieved.
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Rapid X-ray crystal structure analysis in few second measurements using microstrip Gas Chamber
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: Atsuhiko Ochi, Yuji Nishi, Toru Tanimori, Hidenori Toyokawa, Tsutomu Nagayoshi, Hidehiro Uekusa, Yuji Ohashi, Yasuro Nishi, Satoshi KoishiAbstract:Abstract X-ray crystal structure analysis using microstrip Gas Chamber was successfully carried out in a measurement time within a few seconds. The continuous rotation photograph method, in which most of the diffraction peaks can be obtained within one continuous rotation of the sample crystal (without stopping or oscillation), was applied for this measurement. As an example, the structure of a single crystal of ammonium bitartrate ( r =1 mm, spherical) was measured. Diffraction spots from the sample, which were sufficient to obtain crystal structure, were successfully obtained by taking only 2 s measurements with a commercially available laboratory X-ray source.
J.f.c.a. Veloso - One of the best experts on this subject based on the ideXlab platform.
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The Gas proportional scintillation counter/microstrip Gas Chamber hybrid detector
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2003Co-Authors: D.s.a.p. Freitas, J.f.c.a. Veloso, J.m.f. Dos Santos, C. M. B. Monteiro, C.a.n. CondeAbstract:The Gas proportional scintillation counter/microstrip Gas Chamber (GPSC/MSGC) hybrid detector for X-ray spectrometry is described. The detector uses a CsI-coated microstrip plate placed in direct contact with the Gas-filling as the photosensor readout for the GPSC scintillation substituting for the photomultiplier tube (PMT). Usable photosensor maximum gain is limited by optical positive feedback due to the additional scintillation produced in the electron avalanche process at the MSP anodes, in the absence of quenching. A low-photoelectron collection efficiency is achieved in the Gas atmosphere, resulting in a scintillation conversion efficiency that is about a factor of 5 lower than that achieved with PMT-based GPSCs. However, energy resolutions of 11% for 5.9 keV X-rays are achieved with this detector.
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Performance characteristics of a Gas proportional scintillation counter coupled to a microstrip Gas Chamber photosensor
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1999Co-Authors: J.f.c.a. Veloso, J.m.f. Dos Santos, C.a.n. CondeAbstract:A P10-filled microstrip Gas Chamber (MSGC) is used to replace the conventional photomultiplier tube (PMT) as the photosensor for a Gas proportional scintillation counter (GPSC). The vacuum ultra-violet (VUV) scintillation light produced in the xenon-filled GPSC is transmitted through a 1 mm thick high-purity quartz window to the MSGC where it is converted to photoelectrons by a CsI photocathode deposited directly onto the surface of a microstrip plate (MSP). These photoelectrons are afterwards multiplied near the microstrip plate anodes with a charge gain of about 103. The energy resolution achieved for 5.9 keV X-rays is 11.5% which, while not yet as good as the 8% figure for standard GPSC (instrumented with a PMT), is already better than the energy resolution obtained for standard proportional counters. Experimental results are presented and discussed. With this design a compact GPSC is obtained which has the further advantage of being much less sensitive to magnetic fields than PMT-based GPSCs. ( 1999 Elsevier Science B.V. All rights reserved.
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A microstrip Gas Chamber as a VUV photosensor for a xenon Gas proportional scintillation counter
IEEE Transactions on Nuclear Science, 1996Co-Authors: J.f.c.a. Veloso, Jose Lopes, J.m.f. Dos Santos, C.a.n. CondeAbstract:The characteristics of a one-atmosphere xenon Gas proportional scintillation counter (GPSC) instrumented with a novel photosensor are reported. A microstrip Gas Chamber (MSGC) with a CsI photocathode deposited directly onto its electrode surface is used in place of the standard photomultiplier tube assembly to record the scintillation light from xenon. The microstrip electrodes also function as the GPSC second scintillation grid. The combination results in a simple and compact device that demonstrates the linear response characteristics of the scintillation process in xenon.
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A microstrip Gas Chamber based Gas proportional scintillation counter
1995 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, 1Co-Authors: J.f.c.a. Veloso, Jose Lopes, J.m.f. Dos Santos, C.a.n. CondeAbstract:In this work we present the concept of a xenon Gas proportional scintillation counter (GPSC) based on a microstrip Gas Chamber (MSGC) working at atmospheric pressure. For this purpose we use a MSGC having a CsI photocathode directly deposited onto it as the photosensor to detect the VUV scintillation light produced in a GPSC, instead of the usual photomultiplier. The MSGC electrodes also act as the GPSC 2nd scintillation grid. Using this approach a greater simplicity and compactness can be achieved. The performance of a GPSC based on this concept is presented and discussed. The energy resolution obtained is about 17% for 5.9 keV X-rays. The variation of the pulse amplitude with the reduced electric field intensity shows the expected linear behaviour characteristic of the xenon secondary scintillation intensity.
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A Gas proportional scintillation counter coupled to a microstrip Gas Chamber photosensor
1996 IEEE Nuclear Science Symposium. Conference Record, 1Co-Authors: J.f.c.a. Veloso, J.m.f. Dos Santos, C.a.n. CondeAbstract:A P10 filled microstrip Gas Chamber (MSGC) is used to replace the conventional photomultiplier tube as the photosensor for a Gas proportional scintillation counter (GPSC). The VUV scintillation light produced in the xenon Gas of the GPSC is transmitted through a high-purity quartz window to the MSGC where it is converted to photoelectrons by a CsI photocathode deposited directly onto the surface of a microstrip plate (MSP). The microstrip plate also provides the charge amplification in a Gas selected for high gain and quenching. Preliminary experimental results of a study of the performance of this concept are presented.
