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We present an ASIC for a [sup.3]He gas detector to be used in small angle neutron scattering experiments at the Spallation Neutron Source in Oak Ridge. The ASIC is composed of 64 channels with low noise charge amplification, filtering, timing and amplitude measurement circuits, where an innovative current-mode peak-detector and digitizer (PDAD) is adopted. The proposed PDAD provides at the same time peak detection and A/D conversion in real time, at low power, and without requiring a clock signal. The channels share an efficient data sparsification and derandomization scheme, a 30-bit 256 deep FIFO, and low voltage differential signaling. Index Terms--ADC, ASIC, gas detector, peak detector.

A bright neutron source such as the spallation neutron source (SNS) places extreme requirements on detectors including excellent 2-D spatial imaging and high dynamic range. Present imaging detectors have either shown position resolutions that are less than acceptable or they exhibit excessive paralyzing dead times due to the brightness of the source. A detector concept known as MicroMegas (MicroMEsh GAseous Structure) has been developed at CERN, Geneva, Switzerland, for high-energy physics charged-particle tracking applications and has shown great promise for handling high data rates with a rather low-cost structure. We are attempting to optimize the MicroMegas detector concept for thermal neutrons and have designed a 1-D neutron strip detector utilizing solid converters which we have tested. In addition, we are performing research into the compatibility of various converter coatings. Our goal is to develop a manufacturable detector that could be scaled to a 1 [m.sup.2], 2-D array for use at the SNS and other facilities. Index Terms--Neutrons, radiation detector.

Many design techniques have been incorporated into modern CMOS design practices to improve radiation tolerance of integrated circuits. Annular-gate NMOS structures have been proven to be significantly more radiation tolerant than the standard, straight-gate variety. Many circuits can be designed using the annular-gate NMOS and the inherently radiation tolerant PMOS. Bandgap reference circuits, however, typically require p-n junction diodes. These p-n junction diodes are the dominating factor in radiation degradation in bandgap reference circuits. This paper proposes a different approach to bandgap reference design to alleviate the radiation susceptibility presented by the p-n junction diodes. [ABSTRACT FROM PUBLISHER]