RPC with low-resistive phosphate glass electrodes as a candidate for the CBM TOF

Abstract

Usage of electrodes made of glass with low bulk resistivity seems to be a promising way to adapt the Resistive Plate Chambers (RPC) to the high-rate environment of the upcoming CBM experiment. A pilot four-gap RPC sample with electrodes made of phosphate glass, which has bulk resistivity in the order of 10 10 Ω cm, has been studied with MIP beam for TOF applications. The tests have yielded satisfactory results: the efficiency remains above 95% and the time resolution stays within 120 ps up to the particle rate of 18 kHz/cm 2 . The increase in rate from 2.25 to 18 kHz/cm 2 leads to an increase of estimated 'tails' fraction in the time spectrum from 1.5% to 4%.

Conceptual design of the CBM-TOF wall with real-size high-rate MRPC modules based on the newly developed chinese doped glass

“…Since the position resolution of this counter+electronics is known to be 0.8cm, we attribute the effect to multiple scattering, that is expected to be much larger here as compared to the hadron case [4], due to the very low momentum (p=30MeV/c). 2 The observed effect is indeed compatible with the one expected from the setup geometry and the material budget of the RPC itself and the first scintillator upstream. Fig.…”

“…For the purpose of hadron identification, a Time-of-Flight (TOF) wall placed 10m away from the target and with a polar angle coverage of 2.5°-25°, is imperative. The wall features a TOF resolution better than 80ps and an occupancy per cell below 5% over an area of 150m 2 . The challenge is to keep high efficiencies (above 90%) and good time resolutions (less than 80ps) at particle fluxes up to 20kHz/cm 2 , which is not accessible to conventional float-glass MRPCs.…”

“…The wall features a TOF resolution better than 80ps and an occupancy per cell below 5% over an area of 150m 2 . The challenge is to keep high efficiencies (above 90%) and good time resolutions (less than 80ps) at particle fluxes up to 20kHz/cm 2 , which is not accessible to conventional float-glass MRPCs. For this purpose, the R&D activities focus on the development of high-rate MRPCs [2][3][4][5][6].…”

“…The challenge is to keep high efficiencies (above 90%) and good time resolutions (less than 80ps) at particle fluxes up to 20kHz/cm 2 , which is not accessible to conventional float-glass MRPCs. For this purpose, the R&D activities focus on the development of high-rate MRPCs [2][3][4][5][6]. In order to improve the rate capability, a type of low-resistivity doped glass with bulk resistivity on the order of 10 10…”

Simulation on the response of new phosphate glass RPC for γ-rays and e+/e− particles using GEANT3

“…The properties and advantages of low resistive glass electrodes are reported in Ref. [11,12]. However, a phosphate glass RPC [11] is not yet easily produced, as this is the special type of glass which is available in small quantities.…”