| Paper | Title | Other Keywords | Page |
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| THPPC123 | Online Luminosity Optimization at the LHC | experiment, controls, target, proton | 1351 |
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| The online luminosity control of the LHC experiments consists of an automatic slow real-time feedback system controlled by a specific experiment software that communicates directly with an LHC application. The LHC application drives a set of corrector magnets to adjust the transversal beam overlap at the interaction point in order to keep the instantaneous luminosity aligned to the target luminosity provided by the experiment. This solution was proposed by the LHCb experiment and tested first in July 2010. It has been in routine operation during the first two years of physics luminosity data taking, 2011 and 2012, in LHCb. It was also adopted for the ALICE experiment during 2011. The experience provides an important basis for the potential future need of levelling the luminosity in all the LHC experiments. This paper describes the implementation of the LHC application controlling the luminosity at the experiments and the information exchanged that allows this automatic control. | |||
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Poster THPPC123 [1.344 MB] | ||
| THCOBB01 | An Upgraded ATLAS Central Trigger for 2015 LHC Luminosities | detector, timing, electronics, interface | 1388 |
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The LHC collides protons at a rate of ~40MHz and each collision produces ~1.5MB of data from the ATLAS detector (~60TB of data per second). The ATLAS trigger system reduces the input rate to a more reasonable storage rate of about 400Hz. The Level1 trigger reduces the input rate to ~100kHz with a decision latency of ~2.5us and is responsible for initiating the readout of data from all the ATLAS subdetectors. It is primarily composed of the Calorimeter Trigger, Muon Trigger, and the Central Trigger Processor (CTP). The CTP collects trigger information from all Level1 systems and produces the Level--1 trigger decision. The LHC has now shutdown for upgrades and will return in 2015 with an increased luminosity and a center of mass energy of 14TeV. With higher luminosities, the number and complexity of Level1 triggers will increase in order to satisfy the physics goals of ATLAS while keeping the total Level1 rates at or below 100kHz. In this talk we will discuss the current Central Trigger Processor, the justification for its upgrade, including the plans to satisfy the requirements of the 2015 physics run at the LHC.
The abstract is submitted on behalf of the ATLAS Collaboration. The name of the presenter will be chosen by the collaboration and communicated upon acceptance of the abstract. |
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Slides THCOBB01 [10.206 MB] | ||
| THCOCB05 | The LHCb Online Luminosity Monitoring and Control | controls, detector, experiment, target | 1438 |
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| The LHCb experiment searches for New Physics by precision measurements in heavy flavour physics. The optimization of the data taking conditions relies on accurate monitoring of the instantaneous luminosity, and many physics measurements rely on accurate knowledge of the integrated luminosity. Most of the measurements have potential systematic effects associated with pileup and changing running conditions. To cope with these while aiming at maximising the collected luminosity, a control of the LHCb luminosity was put in operation. It consists of an automatic real-time feedback system controlled from the LHCb online system which communicates directly with an LHC application which in turn adjusts the beam overlap at the interaction point. It was proposed and tested in July 2010 and has been in routine operation during 2011-2012. As a result, LHCb has been operating at well over four times the design pileup, and 95% of the integrated luminosity has been recorded within 3% of the desired luminosity. This paper motivates and describes the implementation and the experience with the online luminosity monitoring and control, including the mechanisms to perform the luminosity calibrations. | |||
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Slides THCOCB05 [1.368 MB] | ||