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RPC operation and Hardware Performance. Annual HV module recalibration – all CAEN A3512N HV module offsets recalibrated No current drift in the Endcap RPC after the lowering of the UXC environmental Temperature
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RPC operation and Hardware Performance • Annual HV module recalibration – all CAEN A3512N HV module offsets recalibrated • No current drift in the Endcap RPC after the lowering of the UXC environmental Temperature • The average RPC chamber current per wheel or disk is lower than 3 µA for high luminosity beams. • Number of RPC operated in Single Gap mode is unchanged in 2011: 6 in the Barrel and 20 in the Endcap • Number of active electronic channels is very stable ~ 98.5% • A dedicated HV scan was performed to identify the working point (WP) of each RPC roll and each HV channel • Additional Pressure correction is foreseen to be implemented next TS in order to compensate the P-variations • Stable and Reliable performance of RPC detector during the CMS operation - No RPC DEAD time during recent CMS operation, only 2 RPC problems have caused a downtime to CMS data taking! Defined plateau region Knee 95% HV scan fit ε(HV) = εmax/(1 + eSlope (HV-HV50%)) WP=knee+150V
RPC Trigger Performance • In 2011 the RPC Trigger Efficiency has improved due to: • New 3/6 RPC PAC trigger algorithm: in the barrel at least 3out of 6 available layers are required to be fired in order a muon candidate to be generated. 4 layers were required in 2010. efficiency in the barrel increased • Improved geometrical acceptance: The optical links were rearranged to obtain better geometrical coverage in the gap region between RB0 and RB+/- 1 additional increase of the efficiency in the || ~0.3 • The Entire Online Software was migrated from XDAQ to Trigger Supervisor • Front-end Electronics Threshold Configuration from database • HSCP trigger enabled: The PAC is now able to trigger “slow” particles, which reach the muon system in the next BX . It looks for the coincidence of hits in two consecutive BX, the candidate BX is determined by the BPTX trigger veto. OfflinemuonpT>8GeV/c OfflinemuonpT> 7GeV/c L1 RPC Trigger Efficiency including detector geometrical acceptance and hit efficiency vs L1 CSC or DT trigger
RPC Detector Performance Very Stable Performance after RUN 163233 All RPC chambers working at a fixed applied HV: HV barrel = 9350 Volts SF6 problem + HV scan All RPC chambers working at a fixed applied HV: HV endcap = 9550 Volts SF6 problem + HV scan 20 April 2011 Datataken during the HV scan are analysed and used to define the HV settings per individual HV channel. 3 May 2011 20 April 2011