With the first three years of the LHC running well underway, and luminosity upgrades expected towards the end of the decade, ATLAS and CMS are planning to upgrade their innermost tracking layers with the utmost radiation hard technologies. Chemical Vapour Deposition(CVD) diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for the innermost layer(s) of the upgraded trackers. Recently the CERN RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal CVD diamond sensors to the highest fluences expected at the innermost tracking layers of the HL-LHC. We present beam test results of chemical vapour deposition diamond to fluences in excess of 10^16 protons/cm^2 illustrating that both polycrystalline and single-crystal chemical vapour deposition diamonds follow a single damage curve. We briefly describe the performance of the diamond-based ATLAS beam monitoring devices and discuss plans for their upgrade to a diamond tracker during the 2013/14 LHC consolidation shut-down.
This paper describes the design and implementation of the grounding and shielding system for the ATLAS SemiConductor Tracker (SCT). The mitigation of electromagnetic interference and noise pickup through power lines is the critical design goal as they have the potential to jeopardize the electrical performance. We accomplish this by adhering to the ATLAS grounding rules, by avoiding ground loops and isolating the different subdetectors. Noise sources are identified and design rules to protect the SCT against them are described. A rigorous implementation of the design was crucial to achieve the required performance. This paper highlights the location, connection and assembly of the different components that affect the grounding and shielding system: cables, filters, cooling pipes, shielding enclosure, power supplies and others. Special care is taken with the electrical properties of materials and joints. The monitoring of the grounding system during the installation period is also discussed. Finally, after connecting more than four thousand SCT modules to all of their services, electrical, mechanical and thermal within the wider ATLAS experimental environment, dedicated tests show that noise pickup is minimised.
COBISS.SI-ID: 25962791