Particle Physics Detector Research and Development at Liverpool

1. Particle Physics Detector Research and Development at Liverpool Semiconductor detectors are based on segmented diodes which collect charges produced by ionising radiation The position resolution comes primarily from the granularity which exploits standard microchip processing technology Micron Semiconductor (UK) Ltd have fabricated 50 prototype 9cm  9cm single chip detectors forGLAST using masks designed and purchased by Liverpool Large Area High Granularity One of the 5000 Silicon Modules for the ATLAS Tracker High Radiation Tolerance At the LHC, with a billion high energy (14 TeV) proton collisions per second, radiation levels can easily run to  10 MRad. Better modelling of signal generation in radiation damaged silicon by Liverpool has shown that designs collecting electrons give better charge collection for a given operating voltage than those collecting holes. Prototypes provided by Micron Semiconductor Ltd. CCD-based Linear Collider Vertex Detector Monolithic Active Pixel Prototypes Detectors for the future linear collider will need to measure to a precision of  5m in both dimensions and be less than 50m thick. CCDs and Monolithic Active Pixel Sensors look to offer the required performance. Both options are being studies at Liverpool with RAL and Marconi. NASA’s Gamma-ray Large Area Space Telescope Tracker uses 80m2 of silicon strip detectors. Signal vs voltage for p-type and n-type sensors irradiated to 10 MRad. p-type detectors collect electrons, unlike the other detectors, so can operate efficiently at lower voltages. For areas > 103 m2, need to explore cheaper substrates. Liverpool is looking at the possibility of using diode strips fabricated on conjugated polymer material.

2. The JIF Liverpool Semiconductor Detector Centre (LSDC) The LHC-b Detector for high precision studies of b-quarks at the LHC The LSDC consists of 350m2 of Class 10,000 Clean Rooms plus 100m2 at Class 100 for high density fully automatic wire bonding (200 connections per cm) and probing The LSDC is being equipped with state-of-the-art automatic wire bonding, probing and large volume co-ordinate measuring equipment. Large area assemblies for the ATLAS silicon tracker and LHC-b vertex detector are Liverpool responsibilities, making use of the complex. LHC-b uses back-to-back thinned disks for < 10m precision rand measurement. Integrated thin metal lines route the signals to the electronics. Large area arrays based on sensor modules measuring particles tracks with precision of order 10mrequire low mass support structures of many m2 which do not compromise the intrinsic resolution. The LSDC is complemented by a substantially upgraded workshop with several additional large area, high precision automatic machine tools.