Characteristic study and development of a surface resistivity measuring device for the Resistive Plate Chamber detector

Abstract

The India-based Neutrino Observatory (INO) is an approved multi-institutional experiment of India. It will use maximum 30,000 Resistive Plate Chamber (RPC) of size 2 m × 2 m as an active detector in which each will be sandwiched between two iron plates. Each RPC detectors will be made up of 3 mm thick glass (or Bakelite) plates whose one surface will be coated with graphite paint to work as electrode. To achieve effective and uniform electric field, the coated graphite paint must have uniform distribution over the glass surface. Uniformity can be demonstrated by measuring the surface resistance of the coated graphite paint. However, manual measurement of 60,000 electrodes with the help of multimeter and the jig demands huge amount of person-hour with compromised accuracy, and therefore that requires the need and importance of the automatic scanning system. We have designed an advanced automatic scanning system (ASS) has been developed to fulfill the required needs and overcome the shortcomings of the initially developed system. Measurements are sensitive to the contact pressure between the jig and RPC electrode surface. In this paper, various parameters of the ASS have been precisely fixed. Obtained results are compared with the standard one and found satisfactory within error. It is observed that for obtaining the correct and safe value of surface resistance, applied pressure value in terms of force should be in the range of (9–11) Newton.