Large-area HgI2 pixel detector experiments

The direct deposition of polycrystalline semiconductor HgI2 detectors on pre-deposited specially designed pixel electrodes is described, using two methods, the hot wall vapor deposition, HWVD, and thick film screen print (SP) methods. Some characterization results of the HgI2 material used to facilitate the detectors are described. The pre-deposited substrate is made by standard hybrid technology. The electrode pattern is a 16*16 pixel square pattern each with a size of 1.48 mm and with 0.1 mm spacing; the total area covered by the pixels is (25.28 mm)2 equals 639.078 mm2. In order to fan out the pixels to read-out electronics, holes were made through the ceramic thickness and connecting lines were drawn on the opposite side of the ceramic alumina substrate, where complicated patterns can be produced. The pixel detector is tested with beta particles, and data showing the leakage current vs. bias, are given showing a resistivity of about 2*1012 ohm cm. The current and the average charge signal are reported for three different HgI2 pixel detectors. The signal for one of the detectors is about 1100 electrons at 800 V bias voltage and for the second detector, the resistivity is in the same order of magnitude and the charge collection is somewhat better, reaching 1600 electrons at 700 V. One of the detectors was connected to a second hybrid designed for mounting of 8 castor 1.0 chips. CASTOR 1.0 is a VLSI circuit designed for imaging and the results are being evaluated.

[1]  Claude Colledani,et al.  Castor 1.0, a VLSI analog-digital circuit for pixel imaging applications , 1997 .

[2]  Michael M. Schieber,et al.  Polycrystalline mercuric iodide detectors , 1997, Optics & Photonics.

[3]  Ralph B. James,et al.  CHAPTER 15 - Summary and Remaining Issues for Room Temperature Radiation Spectrometers , 1995 .

[4]  Claude Colledani,et al.  A submicron precision silicon telescope for beam test purposes , 1996 .

[5]  T. Schlesinger,et al.  Semiconductors for room temperature nuclear detector applications , 1995 .

[6]  Towards Imaging with Polycrystalline Mercuric Iodide Semiconductor Detectors , 1997 .

[7]  S. Masciocchi,et al.  VIKING, a CMOS low noise monolithic 128 channel frontend for Si-strip detector readout , 1994 .

[8]  R. Turchetta,et al.  Novel mercuric iodide polycrystalline nuclear particles counters , 1996, 1996 IEEE Nuclear Science Symposium. Conference Record.

[9]  M. Braiman,et al.  Ceramic mercuric iodide semiconductor particle counters , 1997, Conference on the High Energy Radiation Background in Space. Workshop Record.

[10]  M. Braiman,et al.  Evaluation of mercuric iodide ceramic semiconductor detectors , 1998 .

[11]  J. Kaplon,et al.  CASTOR a VLSI CMOS mixed analog—digital circuit for low noise multichannel counting applications , 1996 .

[12]  R. Turchetta,et al.  Spatial resolution of silicon microstrip detectors , 1993 .

[13]  Leonid Melekhov,et al.  Radiation-hard polycrystalline mercuric iodide semiconductor particle counters , 1998 .