Spatial resolution of triple-GEM detectors Kudryavtsev, V.N.; Maltsev, T.V.; Shekhtman, L.I.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Volume:
936
Journal Article
Peer reviewed
Gas Electron Multiplier (GEM) based detectors are widely used in numerous collider experiments and, in particular, at the Budker Institute of Nuclear Physics (BINP). In order to determine the best ...possible spatial resolution, the simulation of charged particle registration process is accomplished. The simulation shows that spatial resolution is definitely less than 20μm for applied operation configurations. The simulation of electron transport through single GEM and through GEM-cascade shows that an electron cluster is compressed by GEM holes and an effective transverse diffusion is reduced by approximately 15% as maximum. The experimental part of the work is devoted to the operability tests of the designed detector with orthogonal strips readout with a pitch of 250μm and the measurements of its characteristics including the dependence of gain on GEM-voltage, the registration efficiency and the spatial resolution. Spatial resolution of the studied detector is measured as 31.5±0.9(stat.)−7.5+6.9(syst.)μm.
In this work we describe simulation and experimental studies of the possible reasons for the observed increase of the maximum gain in multi-GEM devices. Two main hypotheses are analyzed: first, a ...diffusion-dominated charge spread reducing the density in individual holes, acting as independent amplifiers and therefore an increase of the discharge limit with the number of cascaded electrodes; second, the possibility that total avalanche charge before transition to a discharge (Raether limit) strongly depends on the field value and is therefore much higher in cascaded than in single-stage systems.
Gas Electron Multiplier (GEM) based coordinate detectors are used at different high energy physics centres and at Budker Institute of Nuclear Physics particularly. These detectors possess a spatial ...resolution in ten micron scale together with high rate capability up to 107 cm−2s−1. Thus, the precise investigation of best possible spatial resolution, achieved with GEM-detectors, is the subject of interest. The experimental data, accumulated by the moment, gives the possibility to compare it with the simulation results. The simulation of applied detector configurations includes transport of electrons through the detector and tracking of avalanche evolution inside the working volume, as well as obtaining signal distribution on the readout strips. The spatial resolution, obtained in the simulation of an individual detector, is found to be essentially better (the difference is about two standard deviations) than the experimental results. Further efforts to find out the reasons of the contradiction between the simulation and measurements were made. In particular, the simulation of complete experimental set-up (including tracking detectors) was performed. The results of individual detector simulation and the simulation of complete set-up were determined to generally coincide.
This paper describes systematic measurements of the main parameters of the DIMEX-Si silicon microstrip detector prototype, designed to study fast processes in a beam of synchrotron radiation (SR). ...The dynamic range, spatial resolution and temporal parameters of the detector are estimated. The parameters of the prototype silicon detector are compared with the DIMEX-G gas version. The maximum flux which can be measured by the silicon detector is 40 times higher than that of the gas detector. The spatial resolution of the silicon detector is 130 microns and that of the gas detector is 250 microns. The estimated time resolution of the silicon detector is 15 ns, while for a gas detector this value is about 50 ns. All the characteristics of DIMEX-Si are measured with a cycle time of 25 ns. The results of the first tests of a full-scale silicon detector for diffraction studies, operating in the integrating mode at a speed of up to 2 Mframes/s, are also given. The sensor contains 1024 strips 30 mm long with a step of 50 microns; 512 of these strips are connected to readout electronics based on APC128 ASIC. Each chip contains 128 channels, which consist of a low-noise integrator with 32 analog memory cells. The possibility of signal visualization from single photons and electrons from
109
Cd and
90
Sr sources is shown.
The paper describes a detector for carrying out diffraction experiments on a beam of synchrotron radiation, which is being developed at the Institute of Nuclear Physics of the Siberian Branch of the ...Russian Academy of Sciences. The detector will operate in the mode of direct counting of X-ray photons with an energy of more than 3–4 keV. A general description of the detector and its components is given, as well as a detailed description of the recording channel of an application-specific integrated circuit (ASIC). The results of the first measurements of the ASIC parameters are given and discussed in the article.
The work describes a one-dimensional detector for diffraction experiments at a synchrotron radiation beam. The detector is being developed at the Budker Institute of Nuclear Physics, Siberian Branch, ...Russian Academy of Sciences. Until recently the institute was developing gas one-coordinate detectors, in particular a one-coordinate detector with calculated channels (OD-3M), based on the technology of multiwire proportional chambers. To provide a spatial resolution better than 100 microns at a photon energy in a wide energy range (3–30 keV), it is necessary to use solid-state microstrip or matrix sensors in combination with specialized integrated registration circuits. The developed SOCOD detector, using a microstrip sensor based on gallium arsenide as a registration element, operates in the mode of the direct counting of photons with an energy of more than 3–4 keV and a speed of up to 1 MHz/channel. The work gives a general description of the current version of the detector, a block diagram of the registration channel, the software allowing users to control the operation of the detector and display the results obtained, and the developed algorithm for leveling the trigger thresholds in the channels. The results of electronic tests, the work of the alignment algorithm and their discussion are presented.
This paper presents a new integrated circuit designed for signal readout in a silicon microstrip detector in experimental observations of fast processes at a synchrotron radiation beam. The first ...variants of this circuit were used in a prototype detector based on a microstrip silicon sensor and were tested at an intense synchrotron radiation beam at the VEPP-4M storage ring in the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences. The results of the first measurements showed that the main objectives of this development were achieved: the time resolution and frame rate satisfy the initial specifications and the maximum detected signal in a linear mode of operation provides a significant increase in the detected photon flux compared to the previous version of the detector based on gas technology. The main problem detected during testing of the prototype is the relatively high noise level, which will be reduced in the next version of the integrated circuit by optimizing some circuit solutions.
In this work we present experimental data on measuring distributions of small- angle X-ray scattering (SAXS) during cast trinitrotoluene (TNT) detonation of 30 and 40 mm in diameter. Dynamics of ...average size of condensed carbon nanoparticle inkreases has been restored from experimental SAXS data. The work was carried out at the SYRAFEEMA (Synchrotron Radiation Facility for Exploring Energetic Materials) station at accelerator complex VEPP- 4M (Budker Institute of Nuclear Physics). We observe minimal size of particles of order of 2 nm directly behind the detonation front. Later, the average size of carbon nanoparticles increases within 4-12 μs and reach values of 6 nm.
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