Production of long-strip multi-gap resistive plate chamber module for the STAR-MTD system

Abstract

A new Long-strip Multi-gap Resistive Plate Chamber (LMRPC) prototype with 5 gas gaps has been developed for the Muon Telescope Detector (MTD) of the STAR experiment at RHIC in order to reduce the working High Voltage (HV) of previous design. Technical specifications related to the final infrastructure present in the experiment have motivated this effort. Its performance has been measured with cosmic rays. The efficiency of this prototype can reach 98% and the time resolution is around 95 ps. It shows a good uniformity among strips. The noise level is less than 0.2 Hz/cm 2 . The signal transmission and crosstalk of the modules was measured with a vector network analyzer, showing a good match with simulations within the amplifier bandwidth. A new cosmic-ray test system with long scintillators has been developed to accelerate the Quality Control (QC) process during the mass production of STAR-MTD. A selection of perpendicular cosmic-ray events for more accurate evaluation of the time resolution is achieved. The time resolution with this method is better, albeit with larger error, than the result obtained without any selection. A new spacer is used, resulting in a much reduced streamer ratio at comparable fields. Thirty-two modules have been built with the new spacer by the middle of April of 2012. They have been tested and they all have passed the QC.

Detectors and Concepts for sub-100 ps timing with gaseous detectors

“…We refer to the restoration of this ideal situation as 'compensation'. Compensation in timing RPCs was demonstrated in [12], and later employed in the STAR-MTD detector [47]. In the LEPS2 case (figure 2), it is relatively simple to modify the detector geometry by interleaving a thin teflon sheet around the central electrodes, thus decreasing the modal dispersion to about 2 ps/cm, and enabling again a reasonable transmission over 2 m. Main signal characteristics as a function of the propagation distance for the LEPS2 detector.…”

Challenges for resistive gaseous detectors towards RPC2014

“…Some compromise must be accepted then in terms of a reduced efficiency plateau, higher presence of streamers and the subsequent degradation of time resolution. In practice, operation at 90-95% efficiency with resolutions in the range 90-110 ps under SF 6 -free gas mixtures has been convincingly demonstrated up to 1 m-long strip counters [41].…”

Measuring attenuation in signal propagation in Resistive-Plate Chambers

“…For RPCs with the surface resistivity of graphite layers in excess of 1 MΩ/square, signal losses in both induction and propagation have been extensively studied [3,4]. When the surface resistivity of graphite layers is in the region of a few hundred kΩ/square, which is the case for RPCs equipped on LHC detectors [2,5,6], signal loss during the induction process in the RPC has been studied [7,8], while the attenuation in signal propagation, i.e., the loss of charge during signal propagation along the main readout strip, remains unclear.…”