Development of an imaging microstrip gas chamber with a 5 cmx5 cm area based on multi-chip module technology

We have developed a two-dimensional MicroStrip Gas Chamber (MSGC) with a 5 cm x 5 cm detection area based on Multi-Chip Module (MCM) technology. It has a 17 mu m thin substrate, 254 anodes, and 255 back strips both with a 200 mu m pitch. The MSGC was mounted on a large Pin Grid Array (PGA) package having more than 500 pins, which allowed us to readily connect a large number of signals of an imaging MSGC with readout electronics. In this article, we report on the capability of the MSGC as an X-ray imaging detector operated near an intense X-ray source, In order to get stable operation at high X-ray intensity, we found one solution using a similar to 20 mu m substrate and a surface resistivity of similar to 10(15) Omega/square. The control of the surface resistivity was carried out by coating the polyimide substrate with organic titanium. This improvement enabled the MSGC to be stably operated for similar to 10(3) s under a very high counting rate of 10(7) Hz/mm(2). The MSGC is also being operated for several months under medium intensity X-rays from an X-ray generator. In this measurement, high quality digital X-ray images with similar to 60 mu m RMS (Root Mean Square) position resolution were obtained with a simple-readout method of recording only the positions of hit electrodes.