CERN Accelerating science

LHCb Note
Report number	LHCb-PROC-2011-027 ; CERN-LHCb-PROC-2011-027
Title	Kali: The framework for fine calibration of LHCb Electromagnetic Calorimeter
Author(s)	Puig, A (U. Barcelona (main)) ; Savrina, D (Moscow, ITEP) ; Graciani, R (U. Barcelona (main)) ; Belyaev, I (Moscow, ITEP)
Submitted to	Conference on Computing in High Energy and Nuclear Physics 2010, Taipei, Taiwan, 18 - 22 Oct 2010
Submitted by	[email protected] on 03 May 2011
Subject category	Computing and Computers
Accelerator/Facility, Experiment	CERN LHC ; LHCb
Free keywords	LHCb ; Kali
Abstract	The precise calibration (at a level of below 1 %) of the electromagnetic calorimeter (ECAL) of the LHCb experiment is an essential task for the fulfilment of the LHCb physics program. The final step of this task is performed with two calibration methods using the real data from the experimental setup. It is a very CPU-consuming procedure as both methods require processing of $\mathcal{O}10^8$ events which must be selected, reconstructed and analyzed. In this document we present the Kali framework developed within the LHCb software framework, which implements these two final calibration methods. It is integrated with Grid middleware and makes use of parallelism tools, such as python parallel processing modules, to provide an efficient way, both time and disk wise, for the final ECAL calibration. The results of the fine calibration with the very first data collected by the LHCb experiment will also be presented. With the use of the Kali framework it took only two days of processing and allowed to achieve a calibration accuracy of 2-2.5 % for the different ECAL areas.
Copyright/License	Preprint: © 2011-2025 CERN (License: CC-BY-3.0)

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