For the full exploitation of the excellent timing properties of the Multigap Resistive Plate Chamber (MRPC), front-end electronics with special characteristics are needed. These are (a) differential ...input, to profit from the differential signal from the MRPC (b) a fast amplifier with less than 1ns peaking time and (c) input charge measurement by Time-Over-Threshold for slewing correction. An 8-channel amplifier and discriminator chip has been developed to match these requirements. This is the NINO ASIC, fabricated with 0.25μm CMOS technology. The power requirement at 40mW/channel is low. Results on the performance of the MRPCs using the NINO ASIC are presented. Typical time resolution σ of the MRPC system is in the 50ps range, with an efficiency of 99.9%.
The best Coincidence Time Resolution (CTR) obtained so far – with very short crystals of 3–5mm in length – reach values between 100 and 150ps. Such crystals are not really practical for a TOF PET ...imaging device, since the sensitivity is quite small for the detection of the 511keV gammas resulting from a positron annihilation. We present our setup and measurements using 15mm length crystals; a length we regard as reasonable for a TOF-PET scanner. We have used a new series of Silicon Photo-Multipliers (SiPM) manufactured by Hamamatsu. These are the High Fill Factor (HFF) and Low Cross-Talk (LCT) Multi-Pixel Photon Counters (MPPC). We have compared three different crystals, LFS-3 (supplied by Zecotek) and two samples of LYSO (manufactured by Saint Gobain and CPI). We have obtained an excellent value of 148 ps for the Coincidence Time Resolution (CTR) with two LFS-3 crystals (15mm long) mounted on each side of a 22Na radioactive source with the HFF-MPPCs at 3.3V over-voltage. Our results are148ps obtained with LFS-3 and 170ps with LYSO crystals using identical SiPMs and electronics.
Two Multigap Resistive Plate Chambers (MRPCs) were built with thin (0.4 mm) low-resistive glass sheets for the inner plates and standard 0.28 mm ‘soda lime’ float glass as external plates. The 6-gap ...MRPC reaches 96.5% efficiency at 15.6 kV and a time resolution of 68 ps at an instantaneous particle flux around 2.5 kHz/cm2. The 20-gap MRPC reaches 98% efficiency at 18.8 kV and a time resolution of 32 ps. Compared to a 6-gap MRPC built previously with all plates made with soda-lime float glass, the two MRPCs made with low-resistive inner glass show a much higher count rate capability. A third MRPC with all plates made from low-resistive glass was also constructed to verify the operation at high particle flux. In this paper a relative rate capability comparison between the MRPCs has been performed under a pulsed beam with a small spot on the chamber. Their rate capability under full illumination with continuous particle flux needs to be further studied.
This paper reports on the results of time resolution measurements of Multigap Resistive Plate Chamber (MRPC). Three 20 gas gaps MRPCs were built with thin float glass sheets and different gap sizes: ...160μm, 140μm and 120μm. These chambers have been tested using a different gas flow configurations. The measurements indicate that to reach a better time resolution for small gap size (140μm and 120μm), a smaller gas volume of the chamber is preferable. The efficiency of the chambers in both gas flow configurations has been tested. A time resolution of 25 ps comprehensive of the front-end electronics jitter, with an efficiency of 98% has been achieved for the MRPC with 140μm gas gaps; this is the best time resolution. Moreover, all the chambers have been tested for different particle flux. At the highest particle flux tested, a time resolution better than 60 ps together with an efficiency higher than 80% has been achieved for all the detectors at an instantaneous particle flux of 30 kHz∕cm2. From the efficiency and time resolution study, the rate capability for these three MRPC is similar.
The Multigap Resistive Plate Chamber (MRPC) is a possible candidate for the Semi-Digital Hadronic Calorimeter (SDHCAL). Two 4.5×20cm2 active area MRPCs have been built to study the time resolution ...using the NINO ASIC as front-end electronics. The granularity of the active area is provided by a 4 × 16 array of 1×1cm2 pick-up pads. Two different designs have been used for the two chambers: a six gas gap MRPC (6-gap MRPC) with a 220μm gap size and a ten gas gap MRPC (10-gap MRPC) with a 160μm gap size. An efficiency of 95% and 97% has been reached respectively. A time resolution of 50 ps for the 6-gap MRPC and 30 ps for the 10-gap MRPC has been achieved. The multiplicity study of this two MRPCs shows that a large fraction of the single hit is recorded in the events (71% for 6-gap MRPC and 64% for 10-gap MRPC).
A 20 gas gaps multigap resistive plate chamber (MRPC) was built with thin (0.28 mm) glass sheets and 0.16 mm gas gap size. This chamber reaches 97% efficiency at 18.4 kV and a time resolution of ...32 ps (sigma) at an instantaneous particle flux around 2.5 kHz/cm2. Compared to a 6 gaps MRPC with 0.22 mm gas gap, this 20-gap MRPC shows a higher rate capability and much better time resolution. The efficiencies of the 20-gap MRPC reach 95%, 93% and 88% at instantaneous fluxes of 10 kHz/cm2, 14.5 kHz/cm2 and 20 kHz/cm2, respectively. The efficiencies of the 6-gap MRPC at the same flux are 90%, 85% and 77%. The time resolution of 20-gap MRPC degrades with the increase of particle flux. However, a time resolution of 39 ps was obtained at an instantaneous flux of 10 kHz/cm2.
ABSTRACT The Large Volume Detector (LVD) has been continuously taking data since 1992 at the INFN Gran Sasso National Laboratory. The LVD is sensitive to neutrino bursts from gravitational stellar ...collapses with full detection probability over the Galaxy. We have searched for neutrino bursts in LVD data taken over 7,335 days of operation. No evidence of neutrino signals has been found between 1992 June and 2013 December. The 90% C.L. upper limit on the rate of core collapse and failed supernova explosions out to distances of 25 kpc is found to be 0.114 yr−1.
Multigap Resistive Plate Chambers (MRPCs) are often used as time-of-flight (TOF) detectors for high-energy physics and nuclear experiments thanks to their excellent time accuracy. For the Compressed ...Baryonic Matter (CBM) TOF system, MRPCs are required to work at particle fluxes on the order of 1–10kHz/cm2 for the outer region and 10–25kHz/cm2 for the central region. Better time resolution will allow particle identification with TOF techniques to be performed at higher momenta. From our previous studies, a time resolution of 25ps has been obtained with a 20-gap MRPC of 140μm gap size with enhanced rate capability. By using a new type of commercially available thin low-resistivity glass, further improvement MRPC rate capability is possible. In order to study the rate capability of the 10-gap MRPC built with this new low-resistivity glass, we have performed tests using the continuous electron beam at ELBE. This 10-gap MRPC, with 160μm gaps, reaches 97% efficiency at 19.2kV and a time resolution of 36ps at particle fluxes near 2kHz/cm2. At a flux of 100kHz/cm2, the efficiency is still above 95% and a time resolution of 50ps is obtained, which would fulfil the requirement of CBM TOF system.
Abstract
After its successful campaign of measurements beyond the Polar Arctic Circle, the PolarquEEEst experiment measured the cosmic charged particle rate at sea level in a latitude interval ...between 35
$$^{\circ }$$
∘
N and 82
$$^{\circ }$$
∘
N. In this paper, these measurements are described and the corresponding results are discussed.
Various experiments are searching for detectors that can cover large areas (as in the present LHC experiments) with excellent timing performances and insensitivity to magnetic field. A detector based ...on scintillators coupled to SiPM can fulfil these requirements. SiPMs are indeed replacing the standard PhotoMultiplier technology thanks to the many advantages, with the corresponding possibility to achieve also higher segmentations in calorimetry or other applications. Also in view of future colliders experiments like HL-LHC or FCC or medical applications like TOF-PET, an important R&D on timing performances of SiPMs-scintillator detectors has begun, with the goal of including them in the list of possible 4-D tracking-timing devices.
An R&D on SiPM coupled to scintillator time resolution has been performed in a cosmic ray setup. Different kind of SiPMs, geometries of SiPMs coupled to the scintillator and different size of scintillator have been also studied. A time resolution of ∼69 ps, comprehensive of the full electronic chain, from the front-end to the readout electronics, has been achieved with SiPMs coupled to a 2x2x3 cm3 plastic scintillator.
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