Development of large area and of position-sensitive timing RPCs

Abstract

Resistive Plate Chambers (RPC) made with glass and metal electrodes forming accurately spaced gas gaps of a few hundred micrometers have reached timing accuracies below 50 ps s with efficiencies above 99% for MIPs. This type of detector, operating at atmospheric pressure with non-flammable gases, seems well suited for large TOF systems, providing performances comparable to the scintillator-based TOF technology with significantly lower price per channel and being compatible with magnetic fields.In this work, we report recent developments of the timing RPC technology, including a large area counter (0.16 m 2 ) and smaller, position-sensitive, single-gap counters. The latter devices are aimed to be applied in small and accurate TOF systems using a multilayer structure.The large counter has shown a timing resolution between 50 and 75 ps s over the whole active area, with 96% efficiency and very small timing tails, along with a longitudinal position-resolution of 1.2 cm s: The single-gap counters had a timing resolution of 55 ps s and a bi-dimensional position-resolution better than 3 mm FWHM. It was calculated that a 4-layer configuration of such counters would yield a time resolution of 33 ps s essentially free from timing tails. r

Special features of detectors, electronics, and trigger system of the ALICE setup

“…As was mentioned above, the time of flight detec tor has a 7 m length. The radius of the barrel is 3.7 m. The total surface area of the time of flight detector (equal to 160 m 2 ) is divided into 160000 readout chan nels with a 10 m 2 active surface [100,101]. In the final version, microstrips, from which signals are read out, have a surface area of 1.2 × 7 cm 2 .…”

Perspectives for positron emission tomography with RPCs

“…The RPC TOF-PET concept is based on the converter-plate principle [7] and takes advantage of the naturally layered structure of RPCs, of its simple and economic construction, excellent time resolution (60 ps s even for single gaps equipped with position-sensitive readout [8,9]) and very good intrinsic position accuracy (50 mm online in digital readout mode [10]). …”

“…Since such counters are known to deliver a resolution s t E60 ps [8] when irradiated with minimum ionising particles and no optimisation of the mechanical and operational parameters for this application was done yet, further improvements are reasonably to be expected.…”

Single-gap timing RPCs with bidimensional position-sensitive readout for very accurate TOF systems

“…Further details concerning the experimental setup, gas mixture, time readout circuitry and data analysis may be found in Ref. [7].…”