Pixelated resistive Micromegas detector for high-rate environment Alviggi, M.; Camerlingo, M.T.; Pietra, M. Della ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1041
Journal Article
Recenzirano
The R&D work reported in this paper has been devoted to the production and test of pixelated resistive micromegas detectors able to track particles in a high-rate environment, up to 10MHz/cm2, ...keeping a stable gain and a good spatial resolution. To pursue our goal, we had to reduce the occupancy by increasing the detector granularity and this has been done by changing the read-out anodes from the usual strips to pads. This minor change in the electrodes layout drastically increased the difficulty of implementing a resistive structure to protect the anodes from sparking. We present the results of the tests performed on four prototypes, with different protection schemes, showing it is possible to reach the desired rate with high gain, high efficiency and good position resolution. The response to X-rays from low (55Fe source) to high (X-rays generator) rates, as well as to beams of ionizing particles is reported.
Abstract
The new era of particle physics experiments is moving towards new upgrades of present accelerators (Large Hadron Collider at CERN) and the design of high energy (tens/hundreds TeV scale) and ...very high intensity new particle accelerators (FCC-ee/hh, EIC, Muon Collider). Cost effective, high efficiency particle detection in a high background and high radiation environment is fundamental to accomplish their physics program. We present a new high granularity resistive Micromegas detector capable to ensure full efficient and stable operation and a good tracking capabilities up to particle fluxes of 10 MHz/cm
2
. A summary of the detector performances, measured by mean of high intensity X-ray, muon and pion sources, is reported, together with most recent results from test beam activities.
Abstract After exploring different solutions and testing several options, the high granularity resistive Micromegas technology is now mature enough to offer an efficient operation up to particle ...rates of 10 MHz/cm 2 , maintaining the gas amplification above 10 4 , with a large margin before breakdown in order to ensure a stable and reliable operation. The detector exploits small-size readout pads for occupancy reduction and a double Diamond-Like Carbon (DLC) resistive layer with a network of dot-connections to ground for a fast charge evacuation. The double-layer allows preserving the minimum resistance to suppress the discharge intensity for stable operations. The performance measured with particle beams at CERN have shown a spatial resolution below 100 μm for mm-wide readout pads and a few ns time resolution. Now, the technology is being scaled to larger areas, with the construction of detectors with an active area of ∼20×20 cm 2 (already achieved) and new ∼40×50 cm 2 prototypes under construction. An overview of the detector technology, including the latest results, is presented in terms of the gain and rate capability (measured in the laboratory) and efficiency, time and spatial resolution (measured at the CERN SPS). Possible applications in HEP experiments, as well as future developments, are also reported.
The R&D project being presented aims to improve the use of resistive Micromegastechnology in high-energy physics experiments. The project focuses on achieving stable, reliable,and high-gain operation ...at particle flow rates above 1 MHz/cm2 on largesurfaces. To achieve this, the project uses a configuration with small pads readout and requiresinnovative solutions for the spark protection resistive scheme. Different resistive patterns wereinvestigated, and finally the solution based on a double layer of DLC foils was chosen,demonstrating the capability to perform equally for low and high rates under irradiation of X-rayson the full surface of 25 cm2 of the prototype detectors. With this technologyand layout, a detector with an active area of 400 cm2 was recently built. Inthis work we present the results of high-rate capability, robustness, dependence on the irradiatedarea, obtained with high intensity X-rays measurements, as well as the results on efficiency andspatial resolution obtained, at low rates, at CERN SPS with high energy particlebeams. Additionally, preliminary results of pixelized resistive Micromegas time response arereported. With the successful achievements of this detector and the construction of even largersmall-pad resistive Micromegas next year, the project will establish the technology for future usein particle physics and other applications.
We present the development of resistive Micromegas aiming at operation under high rates, up to tens MHz/cm2, focusing on the optimisation of the spark protection resistive layer and the ...miniaturisation of the readout elements. Several Micromegas detectors have been built with an anode plane matrix of 48x16 rectangular readout pads, each pad 0.8x2.8 mm2. The detectors differ for the spark protection resistive schemes being realised with the following techniques: a pad-patterned embedded resistor by screen printing, and uniform DLC (Diamond Like Carbon structure) layers. Characterisation and performance studies of the detectors have been carried out by means of radioactive sources, X-Rays, and test beam. A comparison of the performance obtained with the different resistive layouts is presented, in particular focusing on the response under high irradiation and high rate exposure.
Small-pads resistive Micromegas prototype Di Donato, C.; Alviggi, M.; Camerlingo, M.T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Detectors at future accelerators will require operation at rates up to three orders of magnitude higher than 15 kHz/cm2 the hit rates expected in the current upgrades forward muon detectors of LHC ...experiments. A resistive Micromegas detectors with modified readout system can achieve rate capability up to few MHz/cm2 low occupancy. We present the development of small-pad Micromegas detectors with a pad resistive readout of few mm2 in size, built with the spark protection resistive layer realized with different techniques.
Started few years ago, the goal of this R&D project is to develop a new generation of single amplification stage resistive MPGD based on Micromegas technology with the following characteristics: ...stable and efficient operation up to 10 MHz/cm2 particle flows; high granularity readout with small pads of the order of mm2; reliable and cost-effective production process. The miniaturization of the readout elements and the optimization of the spark protection system, as well as the stability and robustness under operation, are the primary challenges of the project. Several Micromegas detectors have been built with similar anode planes, segmented with a matrix of 48×16 readout pads with a rectangular shape (0.8×2.8 mm2) and with a pitch of 1 and 3 mm in the two coordinates. The active surface is 4.8×4.8 cm2 with a total number of 768 channels, routed off-detector for readout. With this anode/readout layout, the spark protection resistive layer has been realized with two different techniques: a pad-patterned embedded resistor with screen printing, and a uniform DLC (Diamond Like Carbon structure) layer by sputtering. For each technique different configurations and resistivity values have been adopted. For the DLC series, the most recently built prototype exploits the availability of copper clad DLC foils to improve the construction. Characterization and performance studies of the detectors have been carried out by means of radioactive sources, X-Rays, and test beam. A comparison of the performance obtained with the different resistive layout and different configurations are presented, in particular focusing on the response under high irradiation and high rate exposure.
The new generation of particle physics experiments at current and future colliders demands more and more robust detectors. A proposed solution to the stringent requirements are the Small-pad ...Resistive Micormegas. This technology is being developed during recent years, in the framework of the new R&D project RHUM. Different resistive schemes have been implemented. The different behaviours of the embedded resistor layout and the Diamond-Like Carbon (DLC) uniform layers scheme have been studied. Results at very high rate are shown. HV stability studies with two different gases are reported.
One of the main objectives within the community of the Micro-Pattern-Gaseous-Detectors (MPGD) is the design of new detectors for operation with a very high particle flow. This research path is driven ...mainly by future upgrades of existing experiments at high-luminosity LHC or next generation accelerators where gaseous detectors will be operated at rates up to few MHz/cm2, three orders of magnitude higher than nowadays. The goal of our R&D project, started few years ago, is to develop a new generation of single amplification stage resistive MPGD based on Micromegas technology with the following characteristics: stable and efficient operation up to particle fluxes of 10 MHz/cm2; high granularity readout, with pixels of order mm2 and fully integrated electronics; reliable and cost-effective production process. We present here the development status of our small-pads resistive Micromegas prototypes, focusing on the optimization of the spark protection resistive layer. Characterization and performance studies of the prototypes have been carried out by means of radioactive sources, X-Rays and test beams. A comparison of the performance obtained with the different resistive layout realized until now is presented, studying in particular the response under high rate irradiation.
Objectives: Hepatitis C virus (HCV) infection is often associated with cryoglobulinaemia (CG). Peripheral neuropathy (PN) is a comparatively common complication of CG associated with HCV infection ...and it is thought to be attributable to nerve ischaemia. Only few HCV CG patients with PN have been reported. The recent finding of HCV RNA in nerve biopsy specimens has suggested a possible direct role of HCV in the pathogenesis of PN. The authors studied 51 HCV patients to determine the prevalence of CG and to clarify the possible mechanism by which HCV determines the PN. Methods: All the patients were studied clinically, by laboratory tests and electrophysiologically. Twenty eight patients underwent sural nerve biopsy where both morphological and morphometric evaluation of the biopsy specimen was performed, as well as statistical analysis. Results: CG was found in 40 of 51 cases (78%). Polyneuropathy was significantly prevalent in CG+ patients compared with CG− (18 of 40 compared with 1 of 11 patients; p=0.01). HCV CG− patients more frequently developed well defined mononeuropathy or multiple neuropathy when compared with HCV CG+ (10 of 11 compared with 22 of 40; p<0.03). HCV CG+ patients showed significantly higher proportion of rheumatoid factor positivity (p<0.001) and low C4 levels (p=0.001). Nerve biopsy was performed in 25 of 40 HCV CG+ patients and in 3 of 11 HCV CG− patients: epineurial vasculitis was present in 8 of 25 HCV CG+ (32%) and in 2 of 3 HCV CG−. Differential fascicular loss of axons was found in 10 of 25 CG+ (40%) and 1 of 3 CG−, signs of both demyelination and axonal degeneration were present in 7 of 25 CG+ (28%). No significant difference was found in neuropathological features, while histometrical analysis disclosed more severe involvement in CG+ patients. Conclusions: These findings suggest that the presence of CG is a negative predictive factor for the associated PN. Morphological findings in the sural nerve from HCV CG− and CG+ are consistent with an ischaemic mechanism of nerve damage and are against a direct role of the virus in causing the associated PN.
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