Development of a new detector and DAQ systems for iBIX

A new photon-counting 2D detector and time-of-flight (TOF) data-acquisition (DAQ) electronics were developed as a system for iBIX diffractometer in J-PARC. The detector system is composed of two ceramic ZnS/(10)B(2)O(3) scintillator sheets, 256 x 2 wavelength-shifting (WLS) fibers, eight 64 ch multi-anode photomultipliers (PMT), a high-speed 512-channel amplifier and discriminator, and a 512-channel encoder module with FPGA for time and position determination. The scintillator sheets have high detection efficiency, 30% and 45% at 1.8 (A) over bar for 0.2 and 0.3 mm in thickness, respectively. The WLS fibers (0.5-mm square type) are arranged along X and Y directions with gaps of 0.02 mm; therefore the size of one pixel is 0.52 mm. The PMT have 17% of quantum efficiency for the light from WLS fibers. The detective region (133 x 133 mm(2)) has more than 66% in the front face of the detector. The amplifier and discriminator module has 300 MHz of frequency band, fixed gain (60), and 20-300 mV of discriminator level. The encoder module has many coincidence modes including various pattern-matching methods and a centroid-computation method. The pulse-pair resolution is 4-5 mu s. For the DAQ module, we can use both of histogram and event modes for measurement. The recording rate is 5 x 10(5) events/s for the event mode. Maximum number of the time-channel bins is 4096 for the histogram mode. (c) 2008 Elsevier B.V. All rights reserved.