Accurate timing of gamma rays with high-rate Resistive Plate Chambers

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2007-04, Vol.573 (1), p.4-7
• Main Authors: Lopes, L., Pereira, A., Fonte, P., Ferreira Marques, R.
• Format: Article
• Language: English
• Subjects: High-rate; RPC; TOF
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2006.10.245

The counting rate capability of RPCs is strongly conditioned by the availability of suitable resistive materials for the electrodes. For time-of-flight measurements in heavy-ion high-energy physics, the extension of the counting rate capabilities achievable with glass electrodes, around 2 kHz/cm 2, to much higher values is of fundamental importance. To address this issue we developed single-gap tRPCs with electrodes made from metal and from a commercially available ceramic material free of charge-depletion effects. Tests performed with 511 keV photons yielded a time resolution around 90 ps σ. Neither the time resolution nor the efficiency have been affected by background rates of up to 20 kHz/cm 2 produced with photons from an X-ray generator. The present result establishes the practical feasibility of accurate timing measurements with RPCs at rates up to 20 kHz/cm 2, while keeping a time resolution below 100 ps σ.