Multi-gap Resistive Plate Chamber Research Articles

A High-Density Time-to-Digital Converter Prototype Module for BES III End-Cap TOF Upgrade

This paper describes a high-precision time measurement module for the end-cap time-of-flight (ETOF) upgrade of the Beijing Spectrometer (BES III). ETOF is scheduled to be upgraded with the multi-gap resistive plate chambers (MRPCs) instead of a scintillator. The new ETOF of BES III will have 1728 readout channels, which is a big challenge for the readout electronics. The time resolution of the readout electronics system is required to be better than 25 ps. A 9U VME module with 72 time measurement channels is designed to perform the time measurement. The signals, which are produced by the detector and then amplified and discriminated by the attached frontend electronics, are sent to this module. The module, which is named TDIG, uses the CERN HPTDC to achieve high-precision time measurement. There are nine HPTDC chips on the module, and each provides eight channels to realize 72 channels. A series of experiment tests show that the time resolution of the TDIG module is better than 20 ps. We have constructed a beam test system composed of six plastic scintillators, two MRPC modules, and ETOF prototype electronics, which testifies to the time resolution expected. An overall time resolution of less than 45 ps for beam events has been achieved.

A thin float glass MRPC for the outer region of CBM-TOF wall

A Multi-gap Resistive Plate Chamber (MRPC) made out of thin float glass is proposed for the outer region of the time of flight (TOF) system for the Compressed Baryonic Matter experiment at FAIR. Usually MRPCs are assembled with ordinary glass plates of 0.5mm or more thickness, but their rate capability is less than the CBM requirement (1.5kHz/cm2). There are two ways to improve the rate capability. The first way is to reduce the bulk resistivity of the glass plates. The second is to reduce the thickness of the glass plates. Tsinghua University has made significant progress in the development of low resistive glass and high rate MRPCs. In this paper we report on three MRPCs produced with float glass plates of 0.7mm, 0.5mm and 0.35mm thickness. Tests with cosmic rays and X-rays were performed at Tsinghua University. The results show that thin float glass MRPCs work well and have the rate capability necessary to meet the demands of the CBM-TOF outer region. Further studies were performed using a continuous 1GeV deuterium beam at the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR). Time resolution of about 70ps and efficiency higher than 90% were obtained for flux densities up to 3kHz/cm2, exceeding the requirement for the CBM-TOF outer region.

Effect of temperature on MRPC with pad read-outs

To obtain a quantitative understanding of the influence of temperature on the performance of multi-gap resistive plate chambers (MRPCs), we have tested the performance of a 10-gap, 12-pad, 2×2×12 cm2 active area MRPC at different temperatures with cosmic rays. Presented are results from measurements of high-voltage scans, noise rate, dark current, streamer, time resolution, count rate, charge spectrum, and detection efficiency. The test results show that the MRPC performance is significantly affected by temperature arising from the temperature-dependence of the glass resistivity.

A GEANT4 simulation study of BESIII endcap TOF upgrade

A GEANT4-based Monte-Carlo (MC) model is developed to study the performance of endcap time-of-flight (ETOF) at BESIII. It's found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF's readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber (MRPC) with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate (per channel), from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESIII.

The use of multi-gap resistive plate chambers for in-beam PET in proton and carbon ion therapy

On-line verification of the delivered dose during proton and carbon ion radiotherapy is currently a very desirable goal for quality assurance of hadron therapy treatment plans. In-beam positron emission tomography (ibPET), which can provide an image of the β+ activity induced in the patient during irradiation, which in turn is correlated to the range of the ion beam, is one of the modalities for achieving this goal. Application to hadron therapy requires that the scanner geometry be modified from that which is used in nuclear medicine. In particular, PET detectors that allow a sub-nanosecond time-of-flight (TOF) registration of the collinear photons have been proposed. Inclusion of the TOF information in PET data leads to more effective PET sensitivity. Considering the challenges inherent in the ibPET technique, namely limited β+ activity and the effect of biological washout due to blood flow, TOF-PET technologies are very attractive. In this context, the TERA Foundation is investigating the use of resistive plate chambers (RPC) for an ibPET application because of their excellent timing properties and low cost. In this paper we present a novel compact multi-gap RPC (MRPC) module design and construction method, which considering the large number of modules that would be needed to practically implement a high-sensitivity RPC-PET scanner, could be advantageous. Moreover, we give an overview of the efficiency and timing measurements that have been obtained in the laboratory using such single-gap and multi-gap RPC modules.

The EEE experiment project: status and first physics results

The Extreme Energy Events Project is an experiment for the detection of Extensive Air Showers which exploits the Multigap Resistive Plate Chamber technology. At the moment 40 EEE muon telescopes, distributed all over the Italian territory, are taking data, allowing the relative analysis to produce the first interesting results, which are reported here. Moreover, this Project has a strong added value thanks to its effectiveness in terms of scientific communication, which derives from the peculiar way it was planned and carried on.

Studying the counting rate capability of a glass multigap resistive plate chamber at an increased operating temperature

It is shown that a multigap resistive plate chamber made of commercial float glass is capable of sustaining high counting rates at an increased operating temperature. Two glass chambers were investigated on the test beamline of the U-70 accelerator at the Institute for High Energy Physics. The required radiation flux density at the detector was produced by means of radioactive sources. The time resolution of 80 ps or better was attained at a rate of ∼20 kHz/cm2 and an operating temperature of 45°C.

Performance of the ALICE Time-Of-Flight detector at the LHC

The Time-Of-Flight (TOF) detector of the ALICE experiment at the CERN LHC is based on Multi-gap Resistive Plate Chambers (MRPCs) technology. During the 2009-2013 data taking the TOF system had very stable operations with a total time resolution of 80ps. Details of the different calibration procedures and performance with data from collisions at the LHC will be described.

Development of high-rate MRPCs for high resolution time-of-flight systems

We show how the high charged-particle flux (1–20kHz/cm2) expected over the 150m2 large time-of-flight wall of the future Compressed Baryonic Matter experiment (CBM) at FAIR can be realistically handled with Multi-gap Resistive Plate Chambers (MRPCs). This crucial 100-fold increase of the chamber rate capability, as compared to that of standard MRPCs presently employed in experiments resorting to sub-100ps timing, has been achieved thanks to the development of a new type of low-resistive doped glass. Following the encouraging results previously obtained with small counters, two types of modules (active area: ∼150cm2) have been built at Tsinghua University with the new material. The measurements conveyed in this work, obtained with a quasi- minimum ionizing electron beam (γβ≥3), prove their suitability as the building blocks of the present hadron-identification concept of the CBM experiment. Namely, they provide a time resolution better than 80ps and an efficiency above 90% at a particle flux well in excess of 20kHz/cm2 (up to 35–60kHz/cm2), being at the core of a modular concept that is easily scalable. Recent measurements of the electrical and mechanical properties of this new material, together with its long-term behavior, are shortly summarized.

A MRPC prototype for SOLID-TOF in JLab

A prototype of Multi-gap Resistive Plate Chamber (MRPC) for the future SoLID time of flight system at JLab has been developed. The counter, trapezoidal in shape, is assembled with the newly developed low-resistive Chinese glass. It has 10 × 0.25 mm gas gaps and 11 readout strips of different lengths. The strip width is 2.5 cm with a strip-to-strip interval of 3 mm. Preliminary tests performed with cosmic-rays showed an efficiency higher than 95% and a time resolution around 50 ps. Results under diffuse/uniform irradiation performed at JLab with scattered high energy electrons showed a time resolution of 70–80 ps and over-95% efficiency up to an incoming flux of 15 kHz/cm2. These performances meet the requirements of the new time of flight system SoLID-TOF.

A new control and data acquisition system for cosmic ray telescopes based on multigap resistive plate chambers

The upcoming phase of expansion of the telescope network of the EEE project has recently inspired a proposal of redesign of the detector control and monitoring, as well as data acquisition interfaces. The new design results in a very compact and versatile system with a significant cost reduction.The system architecture is described, with emphasis on the integration of data acquisition, trigger and GPS into a single unit. Performances of a fully functional prototype are also reported, as well as plans for future developments.

The EEE Project: cosmic rays, multigap resistive plate chambers and high school students

The Extreme Energy Events Project has been designed to join the scientific interest of a cosmic rays physics experiment with the enormous didactic potentiality deriving from letting it be carried out by high school students and teachers. After the initial phase, the experiment is starting to take data continuously, and the first interesting physics results have been obtained, demonstrating the validity of the idea of running a real physics investigation in these peculiar conditions. Here an overview of its structure and status is presented, together with some studies about detector performance and first physics results.

Aging test of a real-size high rate MRPC for CBM-TOF wall

A new kind of low-resistivity glass has been developed. Its volume resistivity is on the order of 1010 Ω cm and multi-gap resistive plate chambers (MRPCs), once assembled with it, can be operated at a charged particle flux in excess of 25 kHz/cm2, with very small charge build-up at the plates. This new technology has a wide range of application in high energy physics experiments such as FAIR-CBM, LHC-ATLAS or Jlab-SOLID, to mention some. In this paper we report on results related to its long-term behavior (aging). A 6 × 2-pad CBM module has been irradiated by X-rays at a mips-equivalent flux of 15 kHz/cm2, for 300 hours and for a released charge totaling 0.22 C (50 mC/cm2). Tested in an electron beam before and after exposure, no degradation of the detector performances could be appreciated. As expected, compared to common glass MRPCs, the newly developed high rate counter also responds faster to sudden irradiation.

Prototyping a 2m × 0.5m MRPC-based neutron TOF-wall with steel converter plates

A 2 m × 0.5 m large prototype of an MRPC-based (Multi-gap Resistive Plate Chamber) neutron Time-Of-Flight-wall for detecting relativistic neutrons in an energy range from 200 MeV to 1 GeV was successfully designed and realized. It consists of steel plates which convert neutrons via hadronic interactions into charged particles, followed by a 2 × 2 gap MRPC-structure to detect the charged particles. Tests were carried out using 30 MeV electrons with an energy close to the minimum of ionization in order to study the properties of the prototype achieving an efficiency larger than 90 % and a time resolution σt better than 100 ps. For units with an active area of 40 cm × 20 cm and otherwise the same design, quasi-monochromatic neutrons with a peak energy of 175 MeV were utilized to study their response to relativistic neutrons. Detailed Monte Carlo simulations were performed both for the small and for the large modules to simulate their properties to both neutrons and electrons and to study the performance of the final neutron detector assembly with an area of 2 m × 2 m for single-neutron and multi-neutron events.

新型气体探测器MRPC

We review the development of a new type gaseous detector, MRPC (Multi-gap Resistive Plate Chamber, MRPC) in the last decade in China. With the successful operation in the STAR experiment at RHIC (Relativistic Heavy Ion Collider, RHIC) and the outstanding importance in charged particle identification, the MRPC technology has gained extensive interest and progress in the high-energy nuclear and particle physics.

Tests of multigap RPCs for high-η triggers in CMS

In this paper, we report a systematic study of multigap Resistive Plate Chambers(RPCs) for high-η triggers in CMS. Prototype RPC modules with four- and six-gap structureshave been constructed with phenolic high-pressure-laminated (HPL) plates and tested withcosmic muons and gamma rays irradiated from a 200-mCi 137Cs source. The detectorcharacteristics of the prototype multigap RPCs were compared with those of the double-gapRPCs currently used in the CMS experiment at LHC. The mean values for detector charges ofcosmic-muon signals drawn in the four- and six-gap RPCs for the efficiency values in themiddle of the plateau were about 1.5 and 0.9 pC, respectively, when digitized with chargethresholds of 150 and 100 fC, respectively. They were respectively about one third and one fifthof that drawn in the current CMS double-gap RPC with a charge threshold of 200 fC. Weconcluded from the current R&D that use of the current phenolic-HPL multigap RPCs isadvantageous to the high-η triggers in CMS in virtue of the smaller detector pulses.

A realistic design of the CBM-TOF wall based on modules commissioned in-beam

The Compressed Baryonic Matter experiment at thefuture Facility for Antiproton and Ion Research will use a time-of-flight(TOF) wall for hadron identification, which is at the moment planned to bebased on the Multi-gap Resistive Plate Chamber (MRPC) technology. The wallwill be placed at 10m distance from the target, covering an area of theorder of 150 m2. Over such an area, it will provide a time-of-flightresolution of 80 ps, by resorting to ca. 50000 RPC cells (in multi-strip ormulti-pad configuration). Fluxes of quasi-minimum ionizing particles(γβ⩾3) as high as 20 kHz/cm2 can be reachedin the central region, corresponding to the low polar angle/high rapiditysection. We propose here a realistic design for building the TOF wall byresorting to a single technology based on low-resistivity doped glass andrelying on small structural modifications of the modules developed andtested during the last two years. Latest results from the modules aresummarized. A comprehensive analytic discussion on the counter performanceunder non-uniform beams, when neglecting non-local effects, is alsopresented.

粒子探测器在中国科学技术大学的最新进展

We review the research and development of some new type detectors: GEM (Gas Electron Multiplier), MicroMegas (Micro Mesh Gaseous Structure), MRPC (Multi-gap Resistive Plate Chamber), Thin-gap RPC, electromagnetic calorimetor and PMT with large dynamic range in the last decade at USTC.

A glass type Multistrip-MRPC prototype for the low rate region of the CBM Time-of-Flight wall

The Compressed Baryonic Matter spectrometer (CBM) is expected to be operational in the year 2018 at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. The key element providing hadron identification at incident energies between 2 and 10 AGeV is a Time-of-Flight (ToF) wall covering the polar angular range from 2.5°–25° and full azimuth. The necessary particle identification capabilities require a 80 ps system time resolution at high efficiency and, simultaneously, a rate capability of up to 25 kHz/cm2. The existing conceptual design foresees a 120 m2 ToF-wall composed of Multi-gap Resistive Plate Chambers (MRPC) which is subdivided in five rate depending concentric arranged regions named A to E where A is the area having fluxes below 1 kHz/cm2 in average. For this region A which covers approximately 55% of the total area we developed a Multistrip-MRPC containing float glass as resistive electrode material. In this paper we present the design of this prototype and in particular results obtained during in beam tests at GSI/SIS18 at Darmstadt and COSY at Jülich.

Status and performance of the ALICE MRPC-based Time-Of-Flight detector

ALICE is the dedicated heavy-ion experiment at the CERN LHC. One of the main detectors devoted to charged hadron identification in the ALICE central barrel is a large Time-Of-Flight (TOF) array; it allows separation among pions, kaons and protons up to a few GeV/c, covering the full azimuthal angle and −0.9 < η < 0.9. The very good performance required for such a system has been achieved by means of the Multigap Resistive Plate Chamber (MRPC) whose intrinsic time resolution is better than 50 ps with an overall efficiency close to 100% and a large operational plateau; the full array consists of 1593 MRPCs covering a cylindrical surface of 141 m2. In this report, the status of the TOF detector and the performance achieved during the 2010 and 2011 data taking periods are reported together with selected physics results obtained with pp and Pb-Pb collisions.