No Arabic abstract
A prototype of Multi-strip Multi-gap Resistive Plate chamber (MMRPC) with active area 40 cm $times$ 20 cm has been developed at SINP, Kolkata. Detailed response of the developed detector was studied with the pulsed electron beam from ELBE at Helmholtz-Zentrum Dresden-Rossendorf. In this report the response of SINP developed MMRPC with different controlling parameters is described in details. The obtained time resolution ($sigma_t$) of the detector after slew correction was 91.5$ pm $3 ps. Position resolution measured along ($sigma_x$) and across ($sigma_y$) the strip was 2.8$pm$0.6 cm and 0.58 cm, respectively. The measured absolute efficiency of the detector for minimum ionizing particle like electron was 95.8$pm$1.3 $%$. Better timing resolution of the detector can be achieved by restricting the events to a single strip. The response of the detector was mainly in avalanche mode but a few percentage of streamer mode response was also observed. A comparison of the response of these two modes with trigger rate was studied
The Multi-gap Resistive Plate Chamber (MRPC) is an advanced form of Resistive Plate Chamber (RPC) detector where the gas gap is divided into sub-gaps. MRPCs are known for their good time resolution and detection efficiency for charged particles. They have found suitable applications in several high energy physics experiments like ALICE in LHC, CERN, Geneva, Switzerland, and STAR in RHIC, BNL, USA. As they have very good time resolution and are of low cost, they can be a suitable replacement for very expensive scintillators used in Positron Emission Tomography Imaging. The MRPCs that are being used nowadays are developed with glass electrodes. We have made an attempt to develop a 6-gap MRPC using bakelite electrodes. The outer electrodes are of dimensions 15 cm $times$ 15 cm $times$ 0.3 cm and the inner electrodes are of dimension 14 cm $times$ 14 cm $times$ 0.05 cm. The glossy finished electrode surfaces have not been treated with any oil like linseed, silicone for smoothness. The performance of the detector has been studied measuring the efficiency, noise rate and time resolution with cosmic rays. This effort is towards the development of a prototype for Positron Emission Tomography with the Time-Of-Flight technique using MRPCs. Details of the development procedure and performance studies have been presented here.
Detailed tests and analysis of ageing effects of high irradiation dose on Multi-Strip Multi-Gap Resistive Plate Counters based on low resistivity glass electrodes were performed. MSMGRPC efficiency and cluster size before irradiation are measured and compared with their values after irradiation in a high irradiation dose accessed at a multi-purpose irradiation facility of IFIN-HH based on $^{60}$Co source. The composition and properties of the deposited layers on the glass electrodes, studied based on a multitude of analysis methods, i.e. SEM, XPS, foil-ERDA, RBS, AFM and THz-TDS, are presented.
The India-based Neutrino Observatory Project (INO) is a proposed underground high energy physics experiment at Theni, India to study the neutrino oscillation parameters using atmospheric neutrinos. The 50 kton magnetised INO-ICAL detector will require approximately 30,000 of 2m$times$2m Resistive Plate Chambers (RPC) as sensitive detectors and proposed to operate for about 20 years. For success of the experiment, each of the RPCs has to function without showing any significant aging during the period of operation. Hence, various tests including a proper leak test are performed during and after production. The methods of leak rate calculation using conventional manometer are valid only when both the volume of the test subject and ambient pressure are kept constant. But both these quantities for a RPC gas gap depend widely on the ambient pressure and temperature. A proper quantitative estimation of the leak rate cannot be acquired from such pressure measurements. By monitoring the absolute pressures, both outside and inside of an RPC, along with the temperature, its leakage rate can be estimated. During the test period, the supporting button spacers inside an RPC may get detached due to manufacturing defect. This effect also needs to be detected.
While in a triggered experiment the matching of the RPC transmission line impedance with the one of the front-end electronics is less critical, for a trigger-less data recording this becomes mandatory. As expected, impedance matching is not straightforward when other requirements in terms of time and position resolutions, efficiency and granularity, have to be fulfilled in the same time. A method and the very first results obtained with a RPC prototype built based on it, presented in this paper, show that the impedance matching, independent of its granularity, can be achieved using an innovative architecture of the RPC.
A new kind of Multi-gap Resistive Plate Chamber (MRPC) has been built for the large-area Muon Telescope Detector (MTD) for the STAR experiment at RHIC. These long read-out strip MRPCs (LMRPCs) have an active area of 87.0 x 17.0 cm2 and ten 250 um-thick gas gaps arranged as a double stack. Each read-out strip is 2.5 cm wide and 90 cm long. The signals are read-out at both ends of each strip. Cosmic ray tests indicate a time resolution of ~70 ps and a detection efficiency of greater than 95%. Beam tests performed at T963 at Fermilab indicate a time resolution of 60-70 ps and a spatial resolution of ~1 cm along the strip direction.