563 research outputs found
Development and integration study of a new front-end electronics for the upgrade of the Resistive Plate Chamber detector for high radiation environment
No full textThe Resistive Plate Chamber (RPC) is a gaseous detector that, by means of a gas mixture as sensing material, reveals the passage of ionizing particles. Two resistive parallel planar electrodes are the basic RPC structure. The applied high voltage generates a strong electric field within the gas, providing directly an avalanche multiplication as soon as a free electron is generated, leading to the absence of any drift time. This unique feature makes it suitable for timing measurements. Moreover, the simple structure and the low cost materials allow its usage for large area applications. The upgrade of the Resistive Plate Chamber detector for the operation in high-background environments consists in the reduction of the operating voltage along with the capability to detect signals as small as 100 μV , moving part of the detector amplification to the Front-End electronics. A new Front-End (FE) electronics has been developed in this thesis project to reach this goal, exploiting a BJT-based preamplifier and a fast discriminator in SiGe BiCMOS technology to improve the detector time resolution and increasing its rate capability. The preamplifier, coupled to the 1-mm gap RPC, has a very low noise (1000 e − rms) and a peaking time of 100 ps. The discriminator has Time-Over-Threshold (TOT) measurement capability and a linear threshold response for signals as fast as 1 ns. The minimum effective threshold on the RPC signals, achievable by this system, is ∼ 100 μV . These RPCs represent a new generation of large area timing detectors, which integrate for the first time a highly performing FE electronics, granting a record time resolution of ∼ 350 ps on a single gas gap of 1 mm with 1.2 mm electrodes thickness. The entire development of this new FE electronics along with the detailed study of the FE integration within the RPC detector will be illustrated in this thesis. Moreover, the results of this new generation of RPC detectors will be shown, particularly in terms of charge threshold achieved (∼ 3 pC) by the electronics and, consequently, the improved detector rate capability (∼ 10 kHz/cm2 ). Furthermore, the application of this newly developed FE electronics is reported, precisely within the ATLAS experiment. The architecture of the present ATLAS Muon Spectrometer (MS) has been designed for a luminosity of 1034 cm−2 s −1 with a security factor of 5 with respect to the simulated background rate, now confirmed by the LHC Run 1 results. Since HL-LHC will have a 5 times higher luminosity and a one order of magnitude bigger background, the demand in terms of performance increases, being the detector operated in a much harsher conditions. The BI-BIS78 projects are part of the LHC Phase-1 and Phase-2 approved upgrades, in order to ensure the demands coming from the physics for the next 20 years. They consists in the installation of an entire new layer of RPC detectors inside the Inner Barrel of the ATLAS experiment. This will ensure higher redundancy and robustness of the trigger system, almost complete acceptance and an improved momentum selectivity. The BIS78 upgrade, scheduled for LHC Phase-1, is the pilot project for the BI RPCs installation. It aims at the installation of 10% of the BI RPCs in the transition region between the endcap and the Inner Barrel of 5 6 CONTENTS ATLAS experiment. This barrel region is the one with the highest background and for this reason is an excellent test bench for the BI upgrade. The BIS78 position will also help in the reduction of the fake muons produced upstream with respect to the cryostats. The BI RPCs represent a new generation of RPCs, basing their largely improved performance on the new and highly performing FE electronics. The BIS78 project, along with the performance achieved by such RPCs, will be shown in this thesis work
Development of an innovative device for high performance tracking measures
No full texthi this paper we present a new Weighting Resistive Matrix (WRM) capable of working for a CCD output. The basic idea is that the luminosity of the pixels defines the position error of the pixel itself. In order to reach this outcome, a variable dispersion is performed. A simple way to obtain this is to vary the dispersion width as a function of the input signal's frequency, proportional to the luminosity of the pixel. This is achieved adding a capacitor to the WRM cell. This new design is capable of performing the straight line fit with a variable position error, as a function of the luminosity
Development of a new front-end electronics in Si and SiGe technology for the Resistive Plate Chamber (RPC) detector for high-rate experiments
No full textThe Resistive Plate Chamber (RPC) detector Front-End (FE) for high-rate experiments is being developed. A mixed technology in silicon and silicongermanium is used in order to enhance its performances: a preamplifier in silicon with a very low inner noise (1000 e− rms) and a new kind of discriminator in SiGe technology with a threshold of the order of 1 mV
BIS78, a pilot project for Phase-2 ATLAS RPC and beyond
No full textThe architecture of the present trigger system in the ATLAS muon barrel was designed according to a reference luminosity of 1034 cm−2s−1 with a safety factor of 5, with respect to the simulated background rates, now confirmed
by LHC Run 1 data. HL-LHC will provide a luminosity 5 times higher and an order of magnitude higher background. As a result, the performance demand increases, the detector being operated under a much harsher condition than the design scenario. The ATLAS Muon Collaboration approved an appropriate upgrade plan, to guarantee the performance required by the physics program for the 20 years scheduled, consisting in installing a layer of new generation Resistive Plate Chambers (RPC) in the inner barrel, to increase the redundancy, the selectivity, and provide almost full acceptance. The BIS78 project aims to install the first 10% of the system already in LS2, at the edges of the inner barrel even sectors (BIS7 and 8). This is the barrel region with the highest background so it is an excellent pilot project for the Phase-2 full coverage. The BIS78 RPCs represent a new generation of the RPC
detectors, based on a new and advanced FE electronics capable to exploit 10 times smaller signals, correspondingly increasing the rate capability. The gas gap has been halved, along with electrodes thickness and weight reduction, improving by a factor of two the time resolution. The performance of the new detectors and the project status are discussed in this document
Performance of the production BIS78 RPC detectors: a new concept of electronics and detector integration for high-rate and fast timing large size RPCs
No full textThe reduction of the average charge per count in the gas along with the capability to discriminate very small avalanche signals, can allow an efficient and long-term Resistive Plate Chamber detector operation, in high radiation background environment. This goal has been reached during the R&D program of the BIS78 ATLAS upgrade project, through the deep integration of a fast (100 ps peaking time) and sensitive (as small as 100 µV threshold) Front-End electronics (FE) with a very large size detector structure. This innovative RPC integration concept pivots on a newly conceived faraday cage, embedding the readout strips and the FE, tightly wrapped around a 1 mm gas gap RPC with 1.2 mm thick electrodes, as a fully independent singlet structure. We studied the performance of BIS78 production triplet chambers, made of 3 independent singlets of 2 m2, each providing a 2D+time information, showing a minimum threshold achievable of 2pC of average charge per count produced inside the gas gap. We show that these chambers grant a record combined performance of better than 95% single gap efficiency, time resolution of 350 ps and ~10 kHz/cm^2 rate capabilit
Optimization of RPCs read-out panel with electromagnetic simulation
No full textWith the upgrade of the RPCs [1, 2] and the increase of its performance, the study and the optimization of the read-out panel is necessary in order to maintain the signal integrity and to reduce the intrinsic crosstalk. Through Electromagnetic Simulation, performed with CST Studio Suite, new panels design are tested and their crosstalk properties are studied. The behavior of different type of panel is shown
The Resistive Cylindrical Chamber
No full textA new generation of gaseous particle detectors named Resistive Cylindrical Chamber (RCC) (Cardarelli, 2021; Rocchi, 2022) [1,2] has been developed to overcome the limitations of Resistive Plate Chambers (Santonico and Cardarelli, 1981) [3] and broaden their application range. The principle behind this new technology consists in the transition from a planar to a cylindrical geometry while maintaining an almost planar electric field. The cylindrical structure of the electrodes allows to reach the following goals: increase the gas pressure to improve the intrinsic efficiency of the detector even for thin gas gaps or light gas mixtures; design the detector in order to produce an electric field gradient possibly useful to contain the development of the avalanche discharge. These features could lead to design detectors of simple mechanical realization with time resolution comparable with that of MRPCs maintaining a high efficiency of detection on a single thin gas-gap. The device pressurization could also allows to use new gases in view of the transition to eco-friendly gas
On a new environment-friendly gas mixture for Resistive Plate Chambers
No full textThe standard gas mixture for the Resistive Plate Chambers (RPC), composed of C2H2F4/i-C4H10/SF6, allows the detector operation in avalanche mode, as required by the high-luminosity collider experiments. The gas density, the low total charge delivered inside the gas and the comfortable avalanche-streamer separation guarantee high detection efficiency, rate capability and slow detector aging. The standard RPC gas mixture is mostly based on Hydrofluorocarbons, HFCs, extensively used in the refrigeration industry. The Hydrofluorocarbons are now considered to be non-eco-friendly gases for their high Global Warming Potential (GWP). The SF6 has the largest GWP, 22 900, but, due to its low concentration, it contributes only with few tens of units to the total value. The major contribution comes from the main standard gas mixture component, the C2H2F4 (GWP ≈ 1300). These gases are not recommended for industrial uses anymore, thus their availability will be increasingly difficult over time and the search for an alternative gas mixture with low-GWP is then of absolute priority within the RPC community. We report the performance of the RPC working with new environment-friendly gases which could replace the standard mixture. In this work the standard mixture main component, the C2H2F4, is replaced by a proper mixture of CO2 (GWP = 1) and Tetrafluoropropene (C3H2F4, GWP≈6). The other high-GWP component, the SF6, is replaced by a molecule, the Chloro-Trifluoropropene (C3H2ClF3, GWP ≈ 5) never tested in RPC detectors. The mixtures studied have a total GWP ≈ 10. We report, for several eco-gas mixtures, the detection efficiency, streamer probability, electronic and ionic charge as a function of the high voltage. Moreover, the timing properties are studied and the detector time resolution is measured. We also focus the attention on a new category of signals having intermediate properties between avalanche and streamer, called ”transition events”. This category is negligible for the standard gas mixture but relevant for HFO/CO2-based gas mixtures. We show a direct comparison between SF6 and C3H2ClF3 to study in depth the possibility to replace the SF6
On a new environment-friendly gas mixture for Resistive Plate Chambers
No full textThis paper studies the performance of RPCs working with a new family of
environment-friendly operating gases, mainly based on Carbon Dioxide and
Hydro-Fluoro-Olefins. The tests are carried out on a 2 mm gap RPC and concern
the measurement of detection efficiency, avalanche-to-streamer transition
probability, prompt and ionic charge delivered. The timing properties of the
new gas are also measured.Comment: 20 pages, 17 figure
Development of novel low-cost gas recirculation system for the RPCs chambers
No full textAn efficient and safe gas mixture recirculation system for Resistive Plate Chambers (RPCs) detector is a crucial
item for planning any future application. The system is based on a special valve that decouples a suction
pump from the RPC, with the aim to keep the pressure inside the chamber in the range from 1 mbar to 3
mbar, regardless of variations in atmospheric pressure, recirculated flow, and temperature. The circulating gas
is flushed in pure water where the impurities developed inside the detector are expected to be soluble and
trappe
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