LHC during week 45 LHC delivered ~0.837 fb-1 in week 45 In total: 20.4fb-1 54 hours of downtime (32%): Cryo Pt 8 ~24 hours. ‘Recovery’ after injector TS & MD ~ 16 hours. SPS flooding ~16 hours. Injection line steering 6+ hours. SPS dump kicker ~4 hours. ALICE ~4 hours. Dump reasons: ATLAS weekly meeting 13.11.2012 Dominic Hirschbühl Bergische Universität Wuppertal

ATLAS Issues LAr FE cooling problem BCM side A noise: still present 2nd pump connected, running continously Access granted twice this week for visual inspection. Intervention during an appropriate moment is considered and discussed. Toroid needs to be off. BCM side A noise: still present noise hunting efforts not successful so far Inclusion of BCM into abort logic and injection permit: after a discussion with BCM, ID, and RC, it was decided to include the BCM again in the abort logic and injection permit will be done after approval of the machine protection panel, likely in two weeks VdM scan request: ATLAS requested a VdM scan early next week (exact time to be confirmed) at beta*=11m, with improved beam conditions (more gaussian tails). CMS will join the scan. Will take ~3 shifts (including setup time) Details to be finalised in the coming days. RPC firmware test with unstretched hits in the trigger requested 40k events for trigger studies in view of 25ns running to be discussed: whether one can use the CMS VdM scan (one trigger configuration, only pre-scale changes). Danger: impact on HLT? ATLAS weekly meeting 13.11.2012 Dominic Hirschbühl Bergische Universität Wuppertal

As per design, the water cooling circuit operates below atmospheric pressure to prevent damage to irreplaceable (and inaccessible) front-end electronics, should a small leak develop. Underpressure is maintained by a vacuum pump which runs briefly whenever the pressure exceeds 0.62 bar; and until the pressure has been brought back down to 0.60 bar. Partial power off of FEB HEC:L1 2nd vacuum pump installed

Schedule No changes w.r.t. to Schedule presented last week ! vdM? No changes w.r.t. to Schedule presented last week ! ~20 days of pp-physics data taking left to go (=3 fb-1?) Magnets: LAr FE cooling: if it is decided by LAr to intervene, we plan to switch off the toroid during MD4 and scrubbing in order to maximise chances for an access during a possible longer downtime of the LHC (e.g. cryo). During MD4: bring down toroid and solenoid for ~1 day for thermosiphon crane handling ATLAS weekly meeting 13.11.2012 Dominic Hirschbühl Bergische Universität Wuppertal

25 vs 50 ns "ATLAS arguments for running with 25 ns bunch spacing after LS1,“ 6/11/2012, ATL-COM-UPGRADE-2012-035: https://cdsweb.cern.ch/record/1484651 These public notes are not intended for journal publication or for submission to the arXiv. This document will form the basis of discussions w.r.t. future LHC running options. This note compares the implications for ATLAS of running the LHC after Long Shutdown 1 (LS1) with 25 ns or 50 ns bunch spacing. For the same instantaneous luminosity, 50 ns spacing gives twice the event pileup per bunch crossing, leading to higher detector occupancy, more combinatorics in the inner detector and higher pileup noise in the calorimeters. The implications for readout bandwidth (in particular for the Inner Detector), trigger, computing and physics are discussed. For all these reasons, ATLAS strongly prefers LHC operation in 2015–2017 at 25 ns from the beginning, both to maximise the utility of the initial 13–14 TeV data samples, and as an essential step on the path to future high luminosities of 2–3×1034 cm−2s−1 and beyond. The same arguments also apply for the period between LS2 and LS3, before the Phase-II tracker upgrade.

This week: Hadron Collider Physics conference First update on Higgs after July discovery announcement and paper

Next week is ATLAS Upgrade week Milano involvements in Phase0 and Phase1. Today: IBL, FTK Phase2: First draft of note "Letter of Intent for the Phase-II Upgrade of the ATLAS Experiment" ATL-COM-UPGRADE-2012-040: https://cdsweb.cern.ch/record/1491186 This will be submitted to the March LHCC and be publicly available at that point. From around 2022, the HL-LHC will operate at a nominal instantaneous luminosity of 5x1034 cm-2 s-1, around twice the expected Phase-I luminosity, with the aim of delivering an integrated luminosity of 2500 fb-1 over ten years. The increased instantaneous luminosity results in the number of interactions per event increasing from 55 to 140, assuming a beam crossing time of 25 ns