科研之友
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摘要
An Integrated Circuit (IC) for processing the signals from CdTe/CdZnTe X-ray detectors in the 5-100 keV energy range is presented. The IC, named CCA, is designed to operate in a capsule for colon 3D-imaging as a diagnostic tool for cancer prevention. The CCA is composed of a low-power consumption analog and a digital sections for counting photons within two energy windows to a maximum of 130 x 10(3) photons per second. The analog section consists of a preamplifier optimized for detectors with 8 pF capacitance, a pulse shaper with 4 shaping times selectable between 0.5 mu s and 2 mu s, a peak stretcher and an analog buffer able to drive up to 15 pF load. The digital section is composed of a two energy windows discriminator fully configurable in the 8.5-120 keV range with 7 bits energy thresholds resolution, two 12 bits counters, two memory registers and an SPI interface for IC configuration and data transfer. The CCA guarantees stable spectroscopic-grade performance allowing for supply voltage variations between 3.1 V to 2.5 V, as is the case of the battery powered capsule during its operation; this feature has been achieved with no voltage regulator for power saving. The CCA has been designed and manufactured in CMOS 0.35 mu m technology, the chip dimensions are 1.25 mm x 0.95 mm. The CCA shows an intrinsic noise of 151 electrons r.m.s. (1.6 keV FWHM in CdTe), a linearity error lower than 1% and a power consumption of 950 mu W at 2.5 V.
- 出版日期2013-10
