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We report on the recent development of a 32-channel low-noise analog front-end ASIC “KW03” for hard X-ray and gamma-ray detectors. The ASIC aims for the readout of strip or pixel (pad) detectors utilizing silicon and cadmium telluride (CdTe) as detector materials. Each readout channel includes a charge-sensitive amplifier, bandpass filters and a sample-and-hold circuit. It also includes a leakage current compensation and pole-zero cancellation circuits to meet the various detector requirements. The equivalent noise level of a typical channel reaches 89 e^- @ 0 pF (rms) and shows an input-capacitance characteristic of 7.5 e^-/pF between 0 pF and 10 pF with a power consumption of 3 mW per channel. We mounted the ASIC on a low-temperature co-fired ceramic (LTCC) package and evaluated the spectral performance by combining with a CdTe diode detector. As a result, the gamma-ray spectrum of radioactive source ^241Am was obtained with a good energy resolution of 2.23 keV (FWHM) for gamma rays of 59.5 keV at -\20~^\circC. [ABSTRACT FROM PUBLISHER]

A 4-sides buttable CdTe-ASIC hybrid module suitable for use in an X-ray flat panel detector (FPD) has been developed by applying through silicon via (TSV) technology to the readout ASIC. The ASIC has 128 × 256 channels of charge integration type readout circuitry and an area of 12.9 mm × 25.7 mm. The CdTe sensor of 1 mm thickness, having the same area and pixel of 100μm pitch, was fabricated from the Cl-doped CdTe single crystal grown by traveling heatermethod (THM). Then the CdTe pixel sensor was hybridized with the ASIC using the bump-bonding technology. The basic performance of this 4-sides buttable module was evaluated by taking X-ray images, and it was compared with that of a commercially available indirect type CsI(Tl) FPD. A prototype CdTe FPD was made by assembling 9 pieces of the 4-sides buttable modules into 3 × 3 arrays in which the neighboring modules were mounted on the interface board. The FPD covers an active area of 77 mm × 39 mm. The results showed the great potential of this 4-sides buttable module for the new real time X-ray FPD with high spatial resolution. [ABSTRACT FROM AUTHOR]

We are developing low noise analog ASICs for hard X-ray and gamma-ray astronomy. They are based on a sub-micron CMOS process. Our design includes a finely-adjustable high-resistance circuit, which, for example, enables us to realize a pole-zero- cancellation in the analog chain. A two-dimensional ASIC with a fast read-out scheme and a one-dimensional ASIC with an improved analog design are developed and verified. With the latter ASIC connected with a CdTe detector, we have obtained a radioactive source spectrum with an energy resolution of 4.6 keV(FWHM) at 59.5 keV. [ABSTRACT FROM AUTHOR]

We developed an eight-channel low-noise analog front-end application specific integrated circuit (ASIC), designated “KW01”, for solid-state radiation detectors. Each channel consists of a charge-sensitive amplifier, band-pass filters, a comparator, and a sample-and-hold circuit. To evaluate its noise performance, we designed a front-end carrier board for mounting the ASIC. By injecting test pulses, we confirmed that the equivalent noise level reaches 110±1.0 e- (rms) at -20 °C. The ASIC was also combined with a Schottky CdTe diode detector for spectral evaluation. As a result, a gamma-ray spectrum of the radioactive source 241Am was obtained with good energy resolutions of 2.43 keV (FWHM) for 59.5 keV gamma rays and 2.26 keV (FWHM) for 17.5 keV gamma rays at -20 °C. [ABSTRACT FROM AUTHOR]