2010/04/30 by Stefanos Dris, Dris, Stefanos
Computer Science · Decision Sciences · Engineering · Physics and Astronomy · #Advanced Data Storage Technologies #Advancements in PLL and VCO Technologies #Distributed and Parallel Computing Systems #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Particle Detector Development and Performance #Scientific Computing and Data Management
paper · pdf · doi:10.48550/arxiv.1004.5574
openalex publication_date 2010/04/30 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
(Abridged version) The CMS experiment at the LHC will begin operation in\n2007. The CMS Tracker sub-detector, comprises ~10 million detector channels\nread out by ~40 000 analog optical links. The optoelectronic components have\nbeen designed to meet the stringent requirements of a HEP experiment in terms\nof radiation hardness, low mass and low power. Extensive testing has been\nperformed on the components and on complete optical links in test systems.\nTheir functionality and performance in terms of gain, noise, linearity,\nbandwidth and radiation hardness is detailed. Particular emphasis is placed on\nthe gain, which directly affects the dynamic range of the detector data. It has\nbeen possible to accurately predict the variation in gain that will be observed\nthroughout the system. A simulation based on production test data showed that\nthe average gain would be ~38% higher than the design target at the Tracker\noperating temperature of -10\degC. Corrective action was taken to reduce the\ngains and recover the lost dynamic range by lowering the optical receiver's\nload resistor value from 100\Ω to 62\Ω. All links will have gains\nbetween 0.64 and 0.96V/V. The future iteration of CMS will be operated in an\nupgraded LHC requiring faster data readout. In order to preserve the large\ninvestments made for the current readout system, an upgrade path that involves\nreusing the existing optoelectronic components is considered. The applicability\nof Quadrature Amplitude Modulation (QAM) in a HEP readout system is examined.\nThe method for calculating the data rate is presented, along with laboratory\ntests where QAM signals were transmitted over a Tracker optical link. The\nresults show that 3-4Gbit/s would be possible if such a design can be\nimplemented (over 10 times the equivalent data rate of the current analog\nlinks, 320Mbits/s).\n