GAPDs in standard CMOS technologies for tracker detectors
by
Eva Vilella(Barcelona)
→
US/Pacific
70A-3377
70A-3377
Description
Amongst other novel sensor technologies, GAPD (Geiger-mode Avalanche PhotoDiode) detectors are being developed to track high energy particles at future linear colliders. These sensors offer outstanding qualities, such as an extraordinary high sensitivity, ultra-fast response time and virtually infinite gain, apart from compatibility with standard CMOS processes. In particular, GAPD detectors enable the direct conversion of a single particle event into a CMOS digital pulse in the sub-nanosecond time scale. As a result, GAPDs can be read out after each single bunch crossing. However, the generated pulses are due not only to the absorbed radiation, but also to the intrinsic noise phenomena of the sensor. Because the noise pulses cannot be distinguished from real particle events and also worsen the detector occupancy, solutions to reduce the sensor noise that are compliant with the severe requirements of the next generation of particle colliders are investigated.
In this talk, a GAPD detector designed and fabricated as a proof of concept of such devices for particle tracking at future linear colliders will be presented. The detector consists of a GAPD pixel array in which the sensors and the readout electronics have been monolithically integrated with a conventional 0.35 µm HV-CMOS process. To reduce the probability of detecting the noise pulses generated by the sensors, the array is operated in a time-gated mode. Measured results demonstrate that the proposed technique, together with the reduction of the working temperature, is advantageous for improving the SNR (Signal-to-Noise Ratio), dynamic range and spatial resolution of the detector. The performance of the GAPD detector in beam-tests at CERN has also been explored. Details about the design and experimental characterization of the GAPD detector will be given at the talk
