The muon system of the Compact Muon Solenoid (CMS) experiment at the LHC is currently not instrumented for pseudorapidity higher than |η|>2.4. The main challenges to the installation of a detector in ...that position are the high particle flux to be sustained, a high level of radiation, and the ability to accomodate a multilevel detector into the small available space (less than 30 cm). A new back-to-back configuration of a Gas Electron Multiplier (GEM) detector is presented with the aim of developing a compact, multi-layer GEM detector. It is composed of two independent stacked triple-GEM detectors, positioned with the anodes toward the outside and sharing the same cathode plane, which is located at the center of the chamber, to reduce the total detector's thickness. A first prototype has been produced and tested with an X-Ray source and muon beam. First results on its performance are presented.
Diamond-Like Carbon for the Fast Timing MPGD Colaleo, A.; De Robertis, G.; Licciulli, F. ...
Journal of physics. Conference series,
04/2020, Letnik:
1498, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The present generation of Micro-Pattern Gaseous Detectors (MPGDs) are radiation hard detectors, capable of detecting effciently particle rates of several MHz/cm2, while exhibiting good spatial ...resolution (≤ 50 µm) and modest time resolution of 5-10 ns, which satisfies the current generation of experiments (High Luminosity LHC upgrades of CMS and ATLAS) but it is not sufficient for bunch crossing identification of fast timing systems at FCC-hh. Thanks to the application of thin resistive films such as Diamond-Like Carbon (DLC) a new detector concept was conceived: Fast Timing MPGD (FTM). In the FTM the drift volume of the detector has been divided in several layers each with their own amplification structure. The use of resistive electrodes makes the entire structure transparent for electrical signals. After some first initial encouraging results, progress has been slowed down due to problems with the wet-etching of DLC-coated polyimide foils. To solve these problems a more in-depth knowledge of the internal stress of the DLC together with the DLC-polyimide adhesion is required. We will report on the production of DLC films produced in Italy with Ion Beam Sputtering and Pulsed Laser Deposition, where we are searching to improve the adhesion of the thin DLC films, combined with a very high uniformity of the resistivity values.
The μ-RWELL detector Bencivenni, G.; Benussi, L.; Borgonovi, L. ...
Journal of instrumentation,
06/2017, Letnik:
12, Številka:
6
Journal Article
Recenzirano
The μ-RWELL has been conceived as a compact, simple and robust Micro-Pattern-Gaseous-Detector (MPGD) for very large area HEP applications requiring the operation in harsh environment. The detector ...amplification stage, similar to a GEM foil, is realized with a polyimide structure micro-patterned with a blind-hole matrix, embedded through a thin Diamond Like Carbon (DLC) resistive layer in the readout PCB. The introduction of the resistive layer strongly suppressing the transition from streamer to spark gives the possibility to achieve large gains (>104), without significantly affecting the capability to stand high particle fluxes. In this work we give an overview of the two detector layouts designed for low and high rate applications, presenting the results of a systematic study of the detector performance as a function of the surface resistivity and discussing the status of the Technology Transfer towards the industry for large area detector manufacturing.
After the Phase-2 high-luminosity upgrade to the Large Hadron Collider (LHC),
the collision rate and therefore the background rate will significantly
increase, particularly in the high $\eta$ region. ...To improve both the tracking
and triggering of muons, the Compact Muon Solenoid (CMS) Collaboration plans to
install triple-layer Gas Electron Multiplier (GEM) detectors in the CMS muon
endcaps. Demonstrator GEM detectors were installed in CMS during 2017 to gain
operational experience and perform a preliminary investigation of detector
performance. We present the results of triple-GEM detector performance studies
performed in situ during normal CMS and LHC operations in 2018. The
distribution of cluster size and the efficiency to reconstruct high $p_T$ muons
in proton--proton collisions are presented as well as the measurement of the
environmental background rate to produce hits in the GEM detector.
We present analytical calculations, Finite Element Analysis modeling, and physical measurements of the interstrip capacitances for different potential strip geometries and dimensions of the readout ...boards for the GE2/1 triple-Gas Electron Multiplier detector in the CMS muon system upgrade. The main goal of the study is to find configurations that minimize the interstrip capacitances and consequently maximize the signal-to-noise ratio for the detector. We find agreement at the 1.5--4.8% level between the two methods of calculations and on the average at the 17% level between calculations and measurements. A configuration with halved strip lengths and doubled strip widths results in a measured 27--29% reduction over the original configuration while leaving the total number of strips unchanged. We have now adopted this design modification for all eight module types of the GE2/1 detector and will produce the final detector with this new strip design.
The High Luminosity LHC (HL-LHC) phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. The foreseen gradual increase of the instantaneous ...luminosity of up to more than twice its nominal value of \(10\times10^{34}\ {\rm cm}^{-1}{\rm s}^{-2}\) during Phase I and Phase II of the LHC running, presents special challenges for the experiments. The region with high pseudo rapidity (\(\eta\)) region of the forward muon spectrometer (\(2.4 > |\eta| > 1.9\)) is not equipped with RPC stations. The increase of the expected particles rate up to 2 kHz cm\(^{-1}\) ( including a safety factor 3 ) motivates the installation of RPC chambers to guarantee redundancy with the CSC chambers already present. The current CMS RPC technology cannot sustain the expected background level. A new generation of Glass-RPC (GRPC) using low-resistivity glass was proposed to equip the two most far away of the four high \(\eta\) muon stations of CMS. In their single-gap version they can stand rates of few kHz cm\(^{-1}\). Their time precision of about 1 ns can allow to reduce the noise contribution leading to an improvement of the trigger rate. The proposed design for large size chambers is examined and some preliminary results obtained during beam tests at Gamma Irradiation Facility (GIF++) and Super Proton Synchrotron (SPS) at CERN are shown. They were performed to validate the capability of such detectors to support high irradiation environment with limited consequence on their efficiency.
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