Timing Resistive Plate Chambers Research Articles

Parallelization of Garfield++ and neBEM to simulate space-charge effects in RPCs

Numerical simulation of avalanches, saturated avalanches, and streamers can help us understand the detector physics of Resistive Plate Chambers (RPC). 3D Monte Carlo simulation of an avalanche inside an RPC, the transition from avalanche to saturated avalanche to streamer may help the search for the optimum voltage and alternate gas mixtures. This task is dauntingly resource hungry, especially when space-charge effects become important, which often coincides with important regimes of operation of these devices. By modifying the electric field inside the RPC dynamically, the space charge plays a crucial role in determining the response of the detector. In this work, a numerical model has been proposed to calculate the dynamic space-charge field inside an RPC and the same has been implemented in the Garfield++ framework. By modeling space charge as large number of line charges and using the multithreading technique OpenMP to calculate electric field, drift line, electron gain, and space-charge field, it has been possible to maintain time consumption within reasonable limits. For this purpose, a new class, pAvalancheMC has been introduced in Garfield++. The calculations have been successfully verified with those from existing solvers and an example is provided to show the performance of pAvalancheMC. Moreover, the details of the transition of an avalanche into a saturated avalanche have been discussed. The induced-charge distribution is calculated for a timing RPC and results are verified with the experiment.

Timing resistive plate chambers for thermal neutron detection with 3D position sensitivity

An optimized design of a neutron detector based on timing RPCs (Resistive Plate Chambers) with boron-10 neutron converters is presented. The detector is composed of a stack of ten double gap RPCs with aluminium cathode plates coated on both sides with 10B4C. This design enables simultaneous determination with high accuracy of both the neutron time-of-flight (down to ns resolution) and the interaction position in 3D (down to 0.25 mm resolution across and ∼1 mm along the beam). It is shown that the detection efficiency can approach 60% for neutrons with lambda = 4.7 Å. A new geometry with less material budget is introduced for the signal pick-up strip arrays. The results of simulation-based optimization of the design are reported considering the trade-off between the detection efficiency, the count rate capability and the amount of elastic scattering on the detector components.

Improving count rate capability of timing RPCs by increasing the detector working temperature

This communication describes test beam results, focusing on detection efficiency and timing precision, of common float glass timing Resistive Plate Chambers (tRPCs) exposed to a 2.7 GeV proton beam and operated at above ambient temperature in order to increase the count rate capability of the chambers, by exploiting the reduction in the resistivity of the glass electrodes. Results suggest that the count rate capability can be extended at least up to 1500Hz/cm2 when the detector is operated at 40.6°C without noticeable loss of efficiency or timing precision degradation with values around 90% and 100 ps, respectively, for this specific timing RPC arrangement.

Precise measurement of gas parameters in a realistic RPC configuration: The currently used R134a gas and a potential alternative eco-gas

In this work, we present a comprehensive method to measure the gas parameters, such as the effective Townsend coefficient and electron drift velocity in homogeneous high electric fields (up to 100kV/cm) at atmospheric pressure and room temperature. A pulsed laser facility with micro-meter spatial accuracy and picosecond pulse duration is used to ignite primary ionizations at specific positions in the gas gap of a Resistive Plate Chamber (RPC) detector prototype. The gas parameters are determined solely by the RPC signals. The main component of the current standard gas for RPC is Tetrafluoroethane (R134a) which has a high Global Warming Potential. Therefore, using Tetrafluoropropene (HFO-1234ze) is under research as an eco-friendly substance. We measure the parameters of these two types of working gases. It is the first direct measurement of the gas parameters of timing RPCs under working conditions. By comparison with existing data from other investigation points, we observe a dependence of gas parameters on the pressure.

New Models of PADI, an Ultrafast Preamplifier–Discriminator ASIC for Time-of-Flight Measurements

The general-purpose PreAmplifier–DIscriminator application-specific integrated circuit (ASIC) chip, PADI, was originally designed to be used as front-end electronics (FEE) for reading out the timing resistive plate chambers in the time-of-flight (TOF) wall of the compressed baryonic matter (CBM) experiment of the future Facility for Antiproton and Ion Research (FAIR) facility in Darmstadt, Germany. Here, we present the last models of this 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology—PADI-X, PADI-XI, and PADI-XII—as well as their key features and test results. While the PADI series was originally developed for high-energy physics experiments carried out at ground facilities, it turned out that PADI is also suitable for space experiments and PADI-X was selected for one sensor of the European Space Agency, JUpiter ICy moons Explore (JUICE) mission. Currently, the most recent model of the series, PADI-XII, has been tuned for space applications and the prototype batch is currently under production.

Atmospheric Temperature Effect in Secondary Cosmic Rays Observed With a 2 m2 Ground‐Based tRPC Detector

AbstractA high time resolution 2 m2 tracking detector, based on timing Resistive Plate Chamber (tRPC) cells, has been installed at the Faculty of Physics of the University of Santiago de Compostela (Spain) in order to improve our understanding of the cosmic rays arriving at the Earth's surface. Following a short commissioning of the detector, a study of the atmospheric temperature effect of the secondary cosmic ray component was carried out. To take into account this effect, temperature coefficients, WT(h), were obtained from cosmic ray data using a method based on Principal Component Analysis (PCA). The results obtained show good agreement with the theoretical expectation. The method successfully removes the correlation present between the different atmospheric layers, which would be dominant otherwise. We briefly describe the initial calibration and pressure correction procedures, essential to isolate the temperature effect. Overall, the measured cosmic ray rate displays the expected anticorrelation with the effective atmospheric temperature, through the coefficient αT=−0.279±0.051%/K. Rates follow the seasonal variations, and unusual short‐term events are clearly identified too.

A timing RPC with low resistive ceramic electrodes

For precise start time determination a Beam Fragmentation T0 Counter (BFTC) is under development for the Time-of-Flight Wall of the Compressed Baryonic Matter Spectrometer (CBM) at the Facility for Antiproton and Ion Research (FAIR) at Darmstadt/Germany. This detector will be located around the beam pipe, covering the front area of the Projectile Spectator Detector. The fluxes at this region are expected to exceed 105cm−2s−1. Resistive plate chambers (RPC) with ceramic composite electrodes could be use because of their high rate capabilities and radiation hardness of material. Efficiency ≥ 97 %, time resolution ≤ 90 ps and rate capability ≥ 105cm−2s−1 were confirmed during many tests with high beam fluxes of relativistic electrons. We confirm the stability of these characteristics with low resistive Si3N4/SiC floating electrodes for a prototype of eight small RPCs, where each of them contains six gas gaps. The active RPC size amounts 20×20 mm2 produced on basis of Al3O2 and Si3N4/SiC ceramics. Recent test results obtained with relativistic electrons at the linear accelerator ELBE of the Helmholtz-Zentrum Dresden-Rossendorf with new PADI-10 Front-end electronic will be presented.

Study of atmospheric Showers Simulations, for Low Energies using Trasgos

In this work we present a new proposal to study the primary radiation mass composition at low energies for atmospheric extended showers (EAS), using detectors called Trasgos (TRack and time reconStructinG bOx). There consist on a stack of timing Resistive Plate Chambers (tRPC) with the advantages of high time and space resolution, as well as tracking capabilities. These characteristics allow us to analyze the arrival of the secondary particles and the fine structure of the EAS front. Our simulations consider the lateral distribution of particles near to the core of the EAS, where the electromagnetic to muonic ratio depends more strongly of the effective cross section, i.e. the mass of the primary particle.

Performance of resistive plate chambers under irradiation of [formula omitted] at relativistic energies

Time resolution and efficiency of single-gap (300μm) multi-strip timing resistive plate chambers (tRPC) have been investigated using 136Xe ions accelerated at 560A MeV with different rates. A time resolution of 37 ps (standard deviation) has been achieved for an irradiation rate of 12Hz∕cm2. The tRPC also provides a detection efficiency above 98%. Our results show that an increase of the irradiation rate clearly leads to a degradation of the time resolution and a quenching of the signal charge.

Fluid modeling of resistive plate chambers: impact of transport data on development of streamers and induced signals

We discuss the implementation of transport data in modeling of resistive plate chambers (RPCs), which are used for timing and triggering purposes in many high energy physics experiments. Particularly, we stress the importance of making a distinction between flux and bulk transport data when non-conservative collisions, such as attachment and/or ionization, are present. A 1.5-dimensional fluid model with photoionization is employed to demonstrate how the duality of transport data affects the calculated signals of the ATLAS triggering RPC and ALICE timing RPC used at CERN, and also a timing RPC with high content. It is shown that in the case of timing RPCs, the difference between the induced charges calculated using flux and bulk transport data can reach several hundred percent at lower operating electric fields. The effects of photoionization and space charge are also discussed.

High-rate timing resistive plate chambers with ceramic electrodes

We describe recent advances in developing radiation-hard ceramic resistive plate chambers (CRPCs) with Si3N4/SiC composites. Bulk resistivity measurements for this material for different manufacturing processes are reported. The results show that the bulk resistivity ρ can vary between 107and1013Ωcm. The varistor type behaviour of the material is analysed. A comparison with other materials used in timing RPCs is given. We describe the assembly and tests of CRPC prototypes in electron and proton beams. For a prototype with ρ~5×109Ωcm, the efficiency of the detectors is 95% at a flux of 2×105cm−2s−1. The time resolution at the same flux is about 120ps. A prototype with ρ~2×1010Ωcm shows an efficiency of about 85% up to fluxes of 5×104cm−2s−1 with a time resolution better than 80ps. The results are compared with RPC models.

English

English

Performance of timing resistive plate chambers with relativistic neutrons from 300 to 1500 MeV

A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic neutrons produced from a deuteron beam of varying energy (300 to 1500 AMeV) in experiment S406 at GSI, Darmstad, Germany. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Measurements of the time of flight jitter of neutrons, in the mentioned energy range, point to a contribution of the resistive plate chamber in the order of 150 ps, independent of the neutron energy.

Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV

A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm2 area.

Resistive Plate Chambers: electron transport and modeling

We study the electron transport in gas mixtures used by Resistive Plate Chambers (RPCs) in high energy physics experiments at CERN. Calculations are performed using a multi term theory for solving the Boltzmann equation. We identify the effects induced by non-conservative nature of electron attachment, including attachment heating of electrons and negative differential conductivity (NDC). NDC was observed only in the bulk component of drift velocity. Using our Monte Carlo technique, we calculate the spatially resolved transport properties in order to investigate the origin of these effects. We also present our microscopic approach to modeling of RPCs which is based on Monte Carlo method. Calculated results for a timing RPC show good agreement with an analytical model and experimental data. Different cross section sets for electron scattering in C2H2F4 are used for comparison and analysis.

Boltzmann equation and Monte Carlo studies of electron transport in resistive plate chambers

A multi term theory for solving the Boltzmann equation and Monte Carlo simulation technique are used to investigate electron transport in Resistive Plate Chambers (RPCs) that are used for timing and triggering purposes in many high energy physics experiments at CERN and elsewhere. Using cross sections for electron scattering in C2H2F4, iso-C4H10 and SF6 as an input in our Boltzmann and Monte Carlo codes, we have calculated data for electron transport as a function of reduced electric field E/N in various C2H2F4/iso-C4H10/SF6 gas mixtures used in RPCs in the ALICE, CMS and ATLAS experiments. Emphasis is placed upon the explicit and implicit effects of non-conservative collisions (e.g. electron attachment and/or ionization) on the drift and diffusion. Among many interesting and atypical phenomena induced by the explicit effects of non-conservative collisions, we note the existence of negative differential conductivity (NDC) in the bulk drift velocity component with no indication of any NDC for the flux component in the ALICE timing RPC system. We systematically study the origin and mechanisms for such phenomena as well as the possible physical implications which arise from their explicit inclusion into models of RPCs. Spatially-resolved electron transport properties are calculated using a Monte Carlo simulation technique in order to understand these phenomena.

Analysis of the Performances of Sealed Timing Resistive Plate Chambers (tRPCs)

Resistive Plate Chambers (RPCs) were introduced by R. Santonico and R. Cardarelli in 1981, are gas ionization chambers made with resistive electrodes separated by precision spacers. Typical gas gap ranges from a few hundred micrometers to several millimeters wide. Timing Resistive Plate Chambers (tRPCs) were introduced in 2000 by P.Fonte, A. Smirnitsky and M.C.S Williams and since then it has reached Time Resolutions better than 50 ps (σ) with efficiencies above 99% for Minimum Ionizing Particle (MIP). In this research paper, we described the main features of gas detectors and the different types of RPCs and their properties. We described the main results that we have got during the operating the sealed tRPCs built in the laboratory.

PADI, an Ultrafast Preamplifier - Discriminator ASIC for Time-of-Flight Measurements

The design of a general-purpose PreAmplifier-DIscriminator ASIC chip, PADI, is presented in this article. PADI is intended to be used as Front-End-Electronics (FEE) for reading out the timing Resistive-Plate Chambers (RPCs) in the time-of-flight (ToF) wall of the CBM detector for the future FAIR facility in Darmstadt-Germany, which will comprise about 100,000 channels in a 150 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area. The evolution of this 0.18 μm CMOS technology design will be presented, from the first prototype PADI-1 to the last one, PADI-8, as well as its features and test results.

Time resolution of resistive plate chambers investigated with 10 MeV electrons

The time resolution of double-gap timing resistive plate chambers (tRPC) has been measured with 10MeV electron bunches of variable intensity. The use of electrons delivered in bunches of a few picoseconds was an attempt to mimic the energy deposition of heavy ions in the tRPC gas gap. The measurements show a clear dependence of the time resolution with the number of electrons per bunch, reaching 21ps (standard deviation) for the highest beam intensity. The signal charge distribution and the time resolution are compared to data obtained with the same detectors for cosmic rays and 238U ions at 1AGeV.

Simulations of a new detection concept for high-energy neutrons based on timing RPCs

In this manuscript we present a novel concept for the detection of relativistic neutrons (between 100 MeV and 1 GeV) based on Resistive Plate Chambers (RPCs). Its principle relies on the detection of charged particles created in hadronic showers induced by the incoming neutrons on the detector constituent materials. The presented design solely considers glass plates as converters for neutron detection while simultaneously delimiting the active gas. For the optimization of a large area detector based on RPCs, simulations using the Virtual Monte Carlo framework FairRoot have been performed. The resulting detector is designed using timing RPC modules, each with 5 gas gaps, that are sequentially grouped, reaching an efficiency for one neutron detection higher than 90%. We show a systematic study on the counter performance as a function of the thickness of the glass plates, and present the design of a prototype to be tested with quasi-monoenergetic neutrons of energies ranging between 200 MeV and 1.5 GeV in the upcoming future.