Multichannel integrated system for fast X-ray imaging applications

We present an integrated system based on a silicon strip detector and integrated circuits (IC) called RG64 for low energy X-ray imaging application. This system is used in fast position sensitive measurements with the possibility of selecting X-ray photons according their energy. The silicon strip detector used in this system has 128 strips with a pitch of 100 μm. The readout integrated circuit RG64 has 64-channel architecture and operates the single photon counting mode. Each channel is built of a charge sensitive amplifier with a second order shaper of 75 ns peaking time, two independent discriminators with an 8-bit offset correction circuit and two independent 20-bit counters with RAM memory buffers. The integrated circuit is optimized for low noise operation in with high frequency of input pulses. The equivalent noise charge of the circuit is equal to 126 el. rms (with 1 pF input load and 5 mW power consumption per single channel) and it operates up to 2 Mcps of average rate of input pulses. The mean gain in the multichannel IC is about 50 μV/el. and the effective threshold voltage spread for given energy calculated to the input is less than 7 el. rms.