arXiv subjects

V. Peskov

Publications and source records attributed to V. Peskov.

66 records · Page 4Linked to original sources

arXiv2002

Perspectives for Positron Emission Tomography with RPCs

In this study we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, making use of the converter-plate principle, takes advantage of the intrinsic layered structure of RPCs and its simple and economic construction. The extremely good time and position resolutions of RPCs also allow the TOF-PET imaging technique to be considered. Monte-Carlo simulations, supported by experimental data, are presented and the main advantages and drawbacks for applications of potential interest are discussed.

physics.ins-det↗

arXiv2002

Novel position-sensitive gaseous detectors with solid photo-cathodes

Currently a revolution is happening in the development of gaseous detectors of photons and particles. Recently developed gaseous detectors with solid photocathodes are now replacing photosensitive wire chambers, which dominated for years in high energy and space flight experiments. We will review the main developments in this field as well as their applications in high-energy physics, medicine, industry and plasma diagnostics. New results on solid photocathodes coupled with gaseous micropattern/wire detectors will also be presented.

physics.ins-det↗

arXiv2002

Aging in gaseous photodetectors

This paper describes the present status of the aging studies in various photosensitive detectors. New experimental data are presented on aging of trimethilamine (TMA) and ethilferrocene (EF) photosensitive vapors as well as on CsI and SbCs photocathodes. A new explanation of the CsI photocathodes aging process based on solid state physics theory is given. Finally, based on our studies, a general conclusion was made that thin polymer depositions on the detector=92s cathode due to the aging can provoke breakdowns through the Malter-type mechanism (or more precisely- an explosive field emission mechanism).

physics.ins-det↗

arXiv2002

Potential of RPCs for tracking

We have demonstrated that small gap (0.1 to 0.4 mm) RPCs made of low resistivity materials (less than 1E8 Ohm.cm) can operate at counting rates of up to 1E5 Hz/mm2 with position resolutions better than 50 micrometer. Results of preliminary tests allow us to suggest a possible application of this new type of RPC for tracking.

physics.ins-det↗

arXiv2002

Studies of Electron Avalanche Behavior in Liquid Argon

Electron avalanching in liquid argon is being studied as a function of voltage, pressure, radiation intensity, and the concentrations of certain additives, especially xenon. The avalanches produced in an intense electric field at the tip of a tungsten needle are initiated by ionization from a moveable americium (241Am) gamma ray source. Photons from xenon excimers are detected as photomultiplier signals in coincidence with the current pulse from the needle. In pure liquid argon the avalanche behavior is erratic, but the addition of even a small amount of xenon (>100ppm) stabilizes the performance. Similar attempts with neon (30%) as an additive to argon have been unsuccessful. Tests with higher energy gamma rays (57Co) yield spectra and other performance characteristics quite similar to those using the 241Am source. Two types of signal pulses are commonly observed: a set of pulses that are sensitive to ambient pressure, and a set of somewhat smaller pulses that are not pressure dependent.

hep-ex↗

arXiv2001

Sporadic electron jets from cathodes - The main breakdown-triggering mechanism in gaseous detectors

We have demonstrated experimentally that the main breakdown-triggering mechanism in most gaseous detectors, including micropattern gaseous detectors, is sporadic electron jets from the cathode surfaces. Depending on conditions, each jet contains randomly from a few primary electrons up to 10^5, emitted in a time interval ranging between 0.1 microsecond to milliseconds. After the emission, these primary electrons experience a full gas multiplication in the detector and create spurious pulses. The rate of these jets increases with applied voltage and very sharply at voltages close to the breakdown limit. We found that these jets are in our measurements responsible for the breakdown-triggering at any counting rate between 10^(-2) Hz/mm^2 and 10^8 Hz/mm^2. We demonstrated on a few detectors that an optimized cathode-geometry, a high electrode surface quality and a proper choice of the gas mixture, considerably improve the performance characteristics and provide the highest possible gains.

physics.ins-det↗

arXiv2001

Evaluation of various planar gaseous detectors with CsI photocathodes for the detection of primary scintillation light from noble gases

Noble gases and liquids are excellent scintillators and this opens a unique opportunity to directly detect the primary scintillation light produced in these media by photons or particles. This signal can be used for several purposes, for example as a start signal for TPCs or for particles identification. Usually photomultipliers (PMs) are used for the detection of the scintillation light. In our previous work we have demonstrated that costly PMs could be replaced by gaseous detectors with CsI photocathodes . Such detectors have the same quantum efficiency as the best PMs but at the same time are cheap, simple and have high position and time resolutions. The aim of this work is to evaluate various planar type gaseous detectors with CsI photocahodes in order to choose the best one for the detection of the primary scintillation light from noble gases and liquids.

physics.ins-det↗

arXiv2001

Detection of the primary scintillation light from dense Ar, Kr and Xe with novel photosensitive gaseous detectors

The detection of primary scintillation light in combination with the charge or secondary scintillation signals is an efficient technique to determine the events t=0 as well as particle / photon separation in large mass TPC detectors filled with noble gases and/or condensed noble gases. The aim of this work is to demonstrate that costly photo-multipliers could be replaced by cheap novel photosensitive gaseous detectors: wire counters, GEMs or glass capillary tubes coupled with CsI photocathodes. We have performed systematic measurements with Ar, Kr and Xe gas at pressures in the range of 1-50 atm as well as some preliminary measurements with liquid Xe and liquid Ar. With the gaseous detectors we succeeded in detecting scintillation light produced by 22 keV X-rays with an efficiency of close to 100%. We also detected the scintillation light produced by bs (5 keV deposit energy) with an efficiency close to 25%. Successful detection of scintillation from 22 keV gammas open new experimental possibilities not only for nTOF and ICARUS experiments, but also in others, like WIMPs search through nuclear recoil emission.

physics.ins-det↗

arXiv2001

Fundamentals of Gas Micropattern Detectors

We performed a new series of systematic studies of gain and rate characteristics of several micropattern gaseous detectors. Extending earlier studies, these measurements were done at various pressures, gas mixtures, at a wide range of primary charges and also when the whole area of the detectors was irradiated with a high intensity x-ray beam. Several new effects were discovered, common to all tested detectors, which define fundamental limits of operation. The results of these studies allow us to identify several concrete ways of improving the performance of micropattern detectors and to suggest that in some applications RPCs may constitute a valid alternative. Being protected from damaging discharges by the resistive electrodes, these detectors feature high gain, high rate capability (10^5 Hz/mm^2), good position resolution (better than 30 micrometer) and excellent timing (50 ps sigma).

physics.ins-det↗

arXiv2001

Gain, Rate and Position Resolution Limits of Micropattern Gaseous Detectors

In this study we report the results of a systematic study of the gain, rate and the position resolution limits of various micropattern gaseous detectors. It was found that at low rates (<1 Hz/mm^2) each detector has it own gain limit, which depends on the size and design features, as well as on gas composition and pressure. However, in all cases the maximum achievable gain is less than or equal to the classical Raether limit. It also was found that for all detectors tested the maximum achievable gain drops sharply with the counting rate. The position resolution of micropattern detectors for detection of X-rays (6 to 35 kV) was also studied, being demonstrated that with solid converters one could reach a position resolution better than 30 micrometers at 1 atm in a simple counting mode.

physics.ins-det↗

arXiv2001

High-resolution TOF with RPCs

In this work we describe some recent results concerning the application of Resistive Plate Chambers operated in avalanche mode at atmospheric pressure for high-resolution time-of-flight measurements. A combination of multiple, mechanically accurate, thin gas gaps and state-of-the-art electronics yielded an overall (detector plus electronics) timing accuracy better than 50 ps sigma with a detection efficiency up to 99% for MIPs. Single gap chambers were also tested in order to clarify experimentally several aspects of the mode of operation of these detectors. These results open perspectives of affordable and reliable high granularity large area TOF detectors, with an efficiency and time resolution comparable to the existing scintillator-based TOF technology but with a significantly, up to an order of magnitude, lower price per channel.

physics.ins-det↗

arXiv1998

Thin gap parallel mesh chamber: a sparkless high-rate detector

In this work we describe a parallel geometry gaseous detector constituted by a thin (0.6 mm) amplifying gap preceded by a drift region. The gap is delimited by a metal plate and by a wire mesh. The detector can count up to a rate of 10^7 Hz/mm2 at gain 1000 and retains at lower counting rates the high gains (close to 10^6) that are typical of parallel geometry detectors. Additionally it was found that in the thin amplifying gap the discharges seem to be self-quenched and that full sparks do not develop. This fact, together with the robustness of the electrode materials, makes this an extremely resilient high-rate detector.

physics.ins-det↗