Microstrip Gas Chamber Research Articles

Fabrication and testing of two-dimensional Micro-Edge Gas Chamber (2D-MEGC)

This work proposes using silver flat ribbon cable to fabricate a new type of position-sensitive gaseous detector. This structure consists of a thin conductive silver of flat ribbon cable (anodes) and thicker copper sheets (cathodes) separated by a plastic insulator. To fix the position of the anodes and the cathodes, a holder compressed the layers. The layers are cut from the edges and polished at several steps to have a smooth surface. These arrays of anodes and cathodes, created by the proposed method, act as a two-dimensional position-sensitive proportional detector. Applying a suitable voltage between the anodes and cathodes produces a strong electric field near the vicinity of the anodes. This electric field multiplies primary electrons generated by ionizing radiation. The experimental results show that for the proposed two Dimensional Micro Edge Gas Chamber (2D-MEGC), at HV1=350 with the gas mixture of (Ar 85% - CO2 15%), the maximum multiplication factor without electric discharge is around 250. All pixels were separately connected to the preamplifier-amplifier setup to test the position sensitivity of 2D-MEGC. As expected for a non-collimated alpha source, the maximum recorded interactions are related to the closest pixel to the radioactive source. The Raether limit is a good benchmark concerning the quality of fabricated gaseous detectors. In the best design conditions, this value for Micro Strip Gas Chamber (MSGCs) is 4 × 107. For the fabricated 2D-MEGC, this number is 2.5 × 107. This result shows that the proposed 2D-MEGC performs well despite its simple structure and fabrication.

Gain measurements of [formula omitted]RWELLs in 3He-CF4 mixtures for thermal neutron detectors

μRWELLs are one of the latest Micro-Pattern Gas Detectors (MPGD) developed in the high-energy community and are widely used within the RD51 collaboration at CERN. Previously, they had only been tested as neutron detectors with the use of thin layers of boron as the neutron converter. Described here are the first ever measurements done with a μRWELL as a neutron detector using 3He gas as the conversion medium. In particular, gain measurements from a μRWELL operating in 3He gas combined with up to 6 bar of CF4 are presented. Among MPGDs, these operating pressures have previously only been achieved by Micro-Strip Gas Chambers (MSGCs).

Micro Edge Gas Chamber (MEGC), a novel detector with the same performance as Micro Strip Gas Chamber (MSGC)

The proposed radiation gas detector has a similar structure as the Micro Strip Gas Chamber (MSGC), but with a different manufacturing process. In this detector, the edges of a stacked Cathode (Copper)/Insulator (Mylar)/Anode (Aluminum)/Insulator (Mylar) sheet sequence have the same performance as the MSGC, so it is called the Micro Edge Gas Chamber (MEGC). Since in the production process of MEGC, it is not necessary to deposit the metals on the substrate, the choice of materials is more flexible. In this way, different insulating materials with suitable conductivity and thickness can be used to improve rate capability and multiplication gain, respectively. In addition, without clean room and state-of-the-art technology, it is possible to fabricate MEGC with very primary instruments. For the gas mixture of (Ar: 70%, CO2:30%), for the alpha particles, the maximum amplification gain of fabricated MEGC is 355, and for the signal-to-noise ratio (SNR) of 15, the full detection efficiency of around 98% can be achieved. For the proposed MEGC, the maximum number of charges before electric discharge (primary charges generated in the drift region multiplied by the multiplication gain) is around 1.1 × 107, and for the best-designed MSGC is 4 × 107. Thus, the proposed detector, despite its simplicity, without any optimization, has a reasonable quality with respect to MSGC.

Anton Oed (1933–2019)

Anton Oed, a passionate inventor and a source of inspiration for many of us today, passed away on September 30, 2018. His introduction of Micro-Strip Gas Chambers (MSGCs) at the Institut Laue-Lange...

Development of a transparent single-grid-type micro-strip gas chamber based on LCD technology

ABSTRACT The liquid crystal display (LCD) technology allows several simple circuits to be built using thin film transistors, thus making fabrication of compact, integrated, large-area, and low-cost micro-pattern gaseous detectors possible. In this work, a single-grid-type micro-strip gas chamber (S-MSGC) using transparent electrodes based on the LCD technology was fabricated and successfully operated in several gas mixtures. The detector was coupled with a multi-pixel photon counter to detect an optical signal through the transparent substrate in Ar/CF4 gas. Both electrical and optical signals were measured and the light yield of the detector was acquired. Successful operation of the S-MSGC can be considered the very important first step for development of the next target of integrated devices.

방사선 위치 검출센서의 제작 및 특성

A microstrip gas chamber (MSGC), applied to digital radiography system, was designed and constructed. The microstrip electrodes were fabricated with Chrome(Cr.). by photolithography process on Silicon(Si) wafer and glass substrate. The width of anode and cathode electrodes was , and , respectively. The distance of the electrodes was , and the active area was . And the number of anode was 80. The microstrip electrodes were damaged when discharges occurred over the 600 V of anode voltage. As the result of experiments. It detected the typical output signals of the pulse width, 20 ns, under the condition that the detecting gas was Ar(90%) + (10%), X-ray tube voltage was 42 kV, and tube current was 1 mA.

Performance of a Micro-Strip Gas Chamber for event wise, high rate thermal neutron detection with accurate 2D position determination

A two-dimensional (2D) position sensitive detector for neutron scattering applications based on low-pressure gas amplification and micro-strip technology was built and tested with an innovative readout electronics and data acquisition system. This detector contains a thin solid neutron converter and was developed for time- and thus wavelength-resolved neutron detection in single-event counting mode, which improves the image contrast in comparison with integrating detectors. The prototype detector of a Micro-Strip Gas Chamber (MSGC) was built with a solid natGd/CsI thermal neutron converter for spatial resolutions of about 100 μm and counting rates up to 107 neutrons/s. For attaining very high spatial resolutions and counting rates via micro-strip readout with centre-of-gravity evaluation of the signal amplitude distributions, a fast, channel-wise, self-triggering ASIC was developed. The front-end chips (MSGCROCs), which are very first signal processing components, are read out into powerful ADC-FPGA boards for on-line data processing and thereafter via Gigabit Ethernet link into the data receiving PC. The workstation PC is controlled by a modular, high performance dedicated software suite. Such a fast and accurate system is crucial for efficient radiography/tomography, diffraction or imaging applications based on high flux thermal neutron beam.In this paper a brief description of the detector concept with its operation principles, readout electronics requirements and design together with the signals processing stages performed in hardware and software are presented. In more detail the neutron test beam conditions and measurement results are reported. The focus of this paper is on the system integration, two dimensional spatial resolution, the time resolution of the readout system and the imaging capabilities of the overall setup. The detection efficiency of the detector prototype is estimated as well.

Demonstration of new possibilities of multilayer technology on resistive microstrip/microdot detectors

The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber and resistive microdot detectors using additional ``field shaping'' strips located inside the detector substrate are described.

Performance Characteristics of the OSMOND Neutron Detector

The performance characteristics of the Off Specular MicrOstrip Neutron Detector (OSMOND) are described. Based on microstrip gas chamber (MSGC) detectors, OSMOND is a high counting rate detector, with sub-millimeter position resolution, capable of replacing the existing rate limited scintillator detectors currently in use on the suite of reflectometer instruments of the ISIS spallation neutron source. The detector system is described together with results of neutron beam tests carried out on the CRISP and POLREF reflectometers.

SPRINTER: A New Detector System for the INTER Neutron Reflectometer

The development and testing of the SuPerior Rate for INTER (SPRINTER) detector is described. Based on a microstrip gas chamber (MSGC), the aim of the project was to produce a matched pair of high-counting-rate detectors capable of replacing the existing 3He tubes currently used on the INTER reflectometer of the ISIS spallation neutron source. The detector system is described, and the results from the first neutron beam tests carried out on an ISIS neutron reflectometer are also shown.

Fast High Resolution Position-Sensitive Gaseous Detectors

The present review describes a new coordinate detectors based on gas micro-pattern technology, which are applied in experiments in elementary particle physics and with SR beams. The microstrip gas chambers (MSGC) on substrates with electronic conductivity are presented in the paper. Such detectors are shown to have spatial resolution better than 100 micron and to be able to effectively operate at particle rates up to 106 s-1mm-2, that at least by two orders of magnitude higher than rate capability of multiwire proportional chambers. Essential part of the review is devoted to studies of the cascades of gas electron multipliers (GEM). In particular, the dependence of gas amplification and conditions of a discharge occurrence on the number of GEMs in cascade, on the distribution of potentials between GEMs in cascade and on gas mixture in the presence of hadron flux are discussed. Gas micro-pattern technology is widely used for the development of coordinate detectors. In the present review we describe as an example the detectors with triple GEM cascades for the tagging system of the KEDR experiment at the VEPP-4M collider

The OSMOND detector

The development and testing of the Off Specular MicrOstrip Neutron Detector (OSMOND) is described. Based on a microstrip gas chamber the aim of the project was to produce a high counting rate detector capable of replacing the existing rate limited scintillator detectors currently in use on the CRISP reflectometer for off specular reflectometry experiments. The detector system is described together with results of neutron beam tests carried out at the ISIS spallation neutron source.

Secondary scintillation in CF4: emission spectra and photon yields for MSGC and GEM

Secondary scintillation (defined here as photon emission originating from electron avalanches) was studied for two gaseous micropattern detectors: MSGC (MicroStrip Gas Chamber) and GEM (Gas Electron Multiplier) operated in pure CF4. For MSGC, the study was performed in the pressure range from 1 to 5 bar; for GEM all experiments were carried out at a fixed pressure of 1 bar. Charge gains from ∼ 10 to ∼ 150 were used in both cases. The primary ionization of the gas was produced by alpha particles from an Am-241 source. Emission spectra of the secondary scintillation were recorded in the wavelength range from 200 to 800 nm and corrected for the response of the detection system. Photon yields (number of photons generated per electron collected at MSGC or GEM) were measured for the integrated UV (200–500 nm) and visible (500–800 nm) emission bands. The obtained emission spectra and photon-per-electron ratios were compared to the corresponding data for the primary scintillation.

Investigations with Gaseous Electron Multipliers for use on the ISIS spallation neutron source

Several investigations have been undertaken to ascertain the suitability of gaseous electron multipliers (GEMs) for use as a neutron detector on the ISIS spallation neutron source. Our initial investigations focused purely on whether these devices could be operated at the elevated pressure of 3He and CF4 necessary for 1mm position resolution (2.6 bars of CF4). In fact we were able to operate the GEMs at suitable gains with 3.5 bars of CF4. However encouraging these results were, we found that the GEMs charged up over time, which we postulated was due to the kapton substrate. A similar problem was seen at the early stages of the development of the microstrip gas chamber (MSGC), a solution of which was to use the semiconducting glass Schott S8900 as the substrate. Therefore we focused our attention to the manufacture of a GEM structure on an S8900 substrate. Our first devices were manufactured from 1mm thick glass and exhibit gains in excess of 1 × 104 for a single GEM stage in an argon isobutane gas mixture, when illuminated with 55Fe x-rays. A small amount of charging under irradiation has been observed in a flowing gas mixture, but the GEMs quickly stabilise and track atmospheric conditions. Further measurements in a 3He:CF4 atmosphere will show how suited these devices are to the needs of ISIS.

Deadtime calibration in high-rate microstrip gas counters

The advent of the microstrip gas chamber (MSGC) has permitted the development of position-sensitive gas avalanche detectors, which combine sub-millimeter spatial resolution with multi-MHz global rate capabilities not attainable with traditional types of gas counters. Based on massively parallel electronic readout, the need to keep down electronic channel costs imposes a simple front-end design without in-built deadtime compensation. In this report we show that insitu calibration of the deadtime of the detector system is straight-forward and reliable. Methods are described for applications to X-ray and neutron detection.

Comparative studies of MSGC and GEM for photon and electron detection at ambient conditions

Experimental work relevant to the electron and photon detection in X-ray Absorption Spectroscopy (XAS) experiments is described using a Micro-Strip Gas Chamber (MSGC) and a Gas Electron Multiplier (GEM) operated at atmospheric pressure. XAS studies at ambient conditions dictate the use of predominately Helium counter gas mixture with minimal quench gas concentration whilst attaining charge gains in the 10 4 region. We present results on the charge gain for both MSGC and GEM detectors using He/iso-C 4H 10 based gas mixtures. Pulse-height distributions due to the Total Electron Yield (TEY) arising from interactions between 8.05 keV X-rays and Titanium sample, i.e. photoelectrons, auger electrons and fluorescent photons, are also presented. Employing a repelling voltage grid close to the sample surface permitted the separation of TEY and the Fluorescent Yield (FY) signal.

Single Photon Counting X-Ray Imaging System Using a Micro Hole and Strip Plate

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A Xe-based single photon counting x-ray imaging system, based on a Micro-Hole &amp; Strip Plate (MHSP), using a resistive charge division method was implemented. The MHSP is a hybrid microstructure that combines in a single element the features of the Gas Electron Multiplier (GEM) and the Micro-strip Gas Chamber (MSGC), presenting two charge multiplication stages. For 2D-imaging, the GEM-like side (top side) is structured with strips orthogonal to the MSGC-like strips at the bottom side. Two thin orthogonal resistive lines of about 100 <formula formulatype="inline"><tex Notation="TeX">$\Omega$</tex></formula>, between the strips (top side) and between the anode strips (bottom side) allows us to obtain the actual position in both <formula formulatype="inline"><tex Notation="TeX">$x$</tex> </formula> and <formula formulatype="inline"><tex Notation="TeX">$y$</tex> </formula> directions. The four signals collected from the edges of the resistive lines are then digitized and processed with a computer. Charge gains of <formula formulatype="inline"><tex Notation="TeX">$10^{4}$</tex></formula> are obtained with the MHSP. Position resolutions of <formula formulatype="inline"><tex Notation="TeX">$\sigma_{x}=130\ \mu{\rm m}$</tex></formula> and <formula formulatype="inline"> <tex Notation="TeX">$\sigma_{y}=250\ \mu{\rm m}$</tex></formula> were achieved for 8-keV x-rays, making it suitable for many applications in single photon x-ray imaging. First x-ray images produced by the system are presented together with a discussion of the image quality and future prospects. </para>

First User Results From the HOTWAXS Detector System

Over the past 10 years combined techniques such as small angle and wide angle X-ray scattering (SAXS/WAXS) and X-ray absorption spectroscopy (XAS) with X-ray diffraction (XRD), have become the mainstay of time resolved experimental studies carried out at synchrotron radiation sources (SRS). However, these techniques have been limited by the detectors used to measure the wide angle scattering/diffraction pattern, and therefore restrict the dynamic experiments that can be studied. The HOTWAXS (High Overall Throughput Wide-Angle X-ray Scattering) detector project was designed to address this issue by producing a position sensitive, parallax free, high count rate, photon counting detector based on microstrip gas chamber (MSGC) technology. The initial experiments, performed on station 16.1 of the Daresbury SRS, with a high density polyethylene sample, confirmed the local count rate per channel to be 1 times 106 counts per second. A global count rate over the 512 channel detector of 27 times 106 counts per second was also measured for this sample. Time resolved experiments on stations 2.1 and 9.3 with real 'user' samples have also been performed, the results of which are presented.

Characteristics of 16-Channel ASIC Preamplifier Board for Microstrip Gas Chamber and Animal PET

A 16-channel ASIC preamplifier board has been designed for microstrip gas chamber (MSGC) and animal position emission tomography (PET) detectors. The highly integrated ASIC chips can be used for individual readouts from a large number of channels to improve the spatial resolution and counting rate. The preamplifier board was tested to have a low optimum equivalent noise charge (ENC) of ~ 1400 e− FWHM at a shaping time of 0.1 μs. The output voltage to input charge gain is 0.96 V/pC, and the nonlinearity is ~ 2:0% over a range of −500 fC to 1000 fC in input charge. The rise time (10%–90%) with no input capacitor is about 54 ns. The power consumption of this preamplifier board is ~ 100 mW. The preamplifier board has been used to read out a 3 × 3 cm MSGC plate and an optimum FWHM energy resolution of 19.1% (5.9 keV peak of Fe-55) was obtained.

The Gridded-Microstrip Gas Chamber as a High Energy Resolution Gaseous X-Ray Detector

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.