Apr 3 – 4, 2008
Europe/Zurich timezone
Combined LHC machine + experiments workshop to: - review the experience from TEVATRON/RHIC/HERA - see what we can expect and optimise from the machine side - see what the LHC experiments require and provide as signals for optimisation Work together to optimise the running conditions aiming at: - safe and stable operation with tolerable backgrounds and radiation - optimisation of the physics potential (maximum integrated luminosity with acceptable background) Notes for writeups and proceedings ===================== It was agreed to prepare written workshop proceedings in "Chamonix workshop" like style, with : 1. Short write ups of each talk by the speaker, about 3 - 5 pages each - to be submitted to the scientific secretaries of the session. In particular for the speakers from outside CERN - please include references or links to relevant talks and papers. 2. Short write up of the discussion sessions by the scientific secretaries - send to the organisers 3. Short written summary by the organisers - H.B. and M.F-L. - and AB-Seminar at CERN on 15 May. http://ab-seminar.web.cern.ch/AB-seminar/talks/AB.Seminar.bgd1.pdf http://ab-seminar.web.cern.ch/AB-seminar/talks/AB.Seminar.bgd2.pdf Format: The format is the same as the Chamonix and Accelerator Conferences, and can be found at http://accelconf.web.cern.ch/AccelConf/JACoW/templates/templates.htm For all contributions, please use the A4 version of this template.
AT Auditorium
The idea for this workshop was triggered by the LHC Machine Advisory Committee. From the executive LHCMAC 21 summary, following a presentation by H. Burkhardt on "Experimental Conditions and Detector Beam Induced Background": The MAC is pleased to see this important activity being carried out as a joint Detector-Accelerator concern. Given the wide experience with these matters at other cryogenic hadron colliders such as the Tevatron, HERA and RHIC, the MAC suggests that a workshop involving the detector and accelerator experts from the corresponding laboratories would be very beneficial in highlighting the various effects and their cures. Beam induced detector backgrounds have been a challenge at all colliders. Catalog of questions ------------------------ Questions to the external machine experts: Are / were machine backgrounds an issue ? Which type ? How was it solved ? Halo : what are the sources. Scraping halo : needed, useful ? Request from the LHC machine to the experiments: It is foreseen to receive detailed signals from the experiments which should allow us to monitor backgrounds. In addition to many, detailed signals, we request few (say two, BKG1, BKG2) normalised figure of merit background signals from each detector. Ideally, they should be representative of backgrounds in the detectors, the running and data quality, and be somewhat complementary. They should be available before stable collisions are declared. Invalid or missing information should be clearly flagged (i.e. flagged with a negative number). If some detector components are reduced in sensitivity or turned off during injection/ramp/squeeze: when will they be turned on based on which information ? Consider to use LHC machine mode and BKG1/2 ? Possible issues , things to be kept in mind : Non-uniformity in the distribution of the backgrounds around the ring depending on positions of collimators and optics phase advance. Scaling of backgrounds with intensity. Increased relative backgrounds for lower luminosity interaction regions. Out off bucket particles, off momentum background.