on CMS information server CMS NOTE 1997 / 061 The Compact Muon Solenoid Experiment
The high radiation environment at the LHC will require the use of radiation hardened microelectronics for the readout of inner detectors. Two such technologies are a Harris bulk CMOS process and the DMILL mixed technology process. Transistors have been fabricated in both of these and have been tested before and after irradiation to 10 Mrads, the total dose expected in the innermost silicon microstrip layers. Several processing runs of Harris transistors have been carried out and samples from one have also been irradiated to 100 Mrads. A preamplifier-shaper circuit, to be used for readout of the CMS microstrip tracker, has been tested and the noise performance is compared with individual transistors.
Measurements of transistors and silicon microstrip detector readout circuits in the Harris AVLSIRA rad-hard CMOS process
Abstract The RD20 collaboration has been developing silicon detectors and front end electronics for inner tracking applications at the proposed Large Hadron Collider (LHC) accelerator at CERN. Prototype amplifier circuits and test structures have been designed and fabricated in a radiation hard bulk CMOS technology (Harris AVLSIRA). Results from measurements of individual transistors and circuits from the first fabrication run in this process are presented, before and after irradiation. The noise performance of the prototype amplifiers is compared with predictions from the transistor noise spectrum measurements, and the optimised performance is predicted.
Radiation tolerance of single-sided silicon microstrips
Abstract The RD20 collaboration is investigating the design and operation of an LHC inner tracking detector based on silicon microstrips. Measurements have been made on prototype detectors after irradiation with electrons, neutrons, photons, and protons for doses up to 5 Mrad and fluences up to 10 15 particles/cm 2 . The annealing of effective doping changes caused by high neutron fluences, one of the major limits to detector lifetime at the LHC, is shown to be strongly inhibited by cooling below room temperature. Detailed results are presented on the critical issue of microstrip capacitance. We have also investigated bulk damage caused by high-energy protons, interstrip isolation after neutron irradiation, and MOS capacitors irradiated with electrons and photons.