The radiation hardness of specific multi-mode and single-mode optical fibres at -25°C beyond a full SLHC dose to a dose of 500 kGy(Si)
Journal of Instrumentation 5 (2010) 11
Abstract:
The optical fibres that will be used in SLHC detectors will be exposed to high doses and low temperatures in the inner detectors. A number of Single-Mode (SM) and Multi-Mode (MM) fibres have been tested for radiation hardness by exposure beyond a full SLHC dose to 500 kGy(Si) in the -25°C operating temperatures expected in the upgraded inner detectors. From these measurements conservative estimates of the level of Radiation Induced Absorption (RIA) have been calculated for these fibres in realistic paths through an upgraded inner detector. Two SM fibres have been found whose total calculated RIAs were much lower than the budgeted 1 dB, despite the high dose rates used in the experiment. The RIAs for the DrakaElite Super RadHard Single-Mode Fiber and Fibre X were calculated to be 0.142 and 0.064 dB respectively. Another SM and a MM fibre showed high levels of RIA during the experiment, however they cannot be ruled out as candidate fibres due the the high dose rate of 27 kGy(Si)/hr used.The radiation hardness of certain optical fibres for the LHC upgrades at -25°C
Proceedings of the Topical Workshop on Electronics for Particle Physics, TWEPP 2009 (2009) 333-337
Abstract:
A luminosity upgrade is planned in the future for the Large Hadron Collider at CERN (called SLHC). Two optical fibres have been tested in a bespoke cold container achieving a constant temperature of ≃ -25°C during the entire exposure. The motivations and results of these tests are presented and two mul-timode and one single mode optical fibre have been identified as candidates for optical links within the joint ATLAS and CMS Versatile Link project.The radiation tolerance of specific optical fibres exposed to 650 kGy(Si) of ionizing radiation
Journal of Instrumentation 4 (2009) 07
Abstract:
The LHC upgrade will extensively increase the area of silicon detectors used in the ATLAS experiment and require substantial changes to the readout system of both the ATLAS and CMS experiments. The two experiments are expected to use optical systems for part of the data and control paths which must withstand levels of radiation equivalent to a dose of approximately 400 kGy(Si) at 30 cm from the collision region (including a safety factor of 1.5). As part of the search for acceptably radiation hard optical fibres, four Graded Index multimode (GRIN) optical fibres and one single-mode (SM) fibre were tested to 650 kGy(Si) equivalent dose. One of the GRIN fibres was also tested at 5 different dose rates, in order to understand the dose rate effects. These tests have validated the radiation tolerance of a single-mode fibre and two multimode fibres for use at the SLHC for warm operation. Some interesting features of the time dependence of the fibre radiation damage and future plans are discussed.Alignment of the pixel and SCT modules for the 2004 ATLAS combined test beam
Journal of Instrumentation 3:9 (2008)