The Cylindrical GEM Detector of the KLOE-2 Experiment Instrumentation for Colliding Beams 2017 Alessandro Di Cicco, Roma Tre University February 27 th – March 3 rd For the KLOE-2 Collaboration Novosibirsk, Russia March 2nd 2017 - A. Di Cicco - INSTR17 1
Th The KLOE-2 2 experiment KLOE-2 is presently taking data at DA 𝜚 NE 𝜚 -factory e + e - collider at √s = 1019.4 MeV [Talk by D. Domenici] Physics Program [EPJ C68 (2010)] • K S , η, η S rare decays • γγ physics • Quantum Interferometry • Dark Photon searches March 2nd 2017 - A. Di Cicco - INSTR17 2
Th The KLOE-2 2 experiment KLOE-2 is presently taking data at DA 𝜚 NE 𝜚 -factory e + e - collider at √s = 1019.4 MeV [Talk by D. Domenici] Physics Program [EPJ C68 (2010)] • K S , η, η S rare decays • γγ physics • Quantum Interferometry HET 11 m from IP • Dark Photon searches ECAL Calorimeter System ECAL - Pb/Scint Fibers w PMTs • CCALT LET - LYSO+SiPMs • HET - Scint+PMTs [Talk by F. Curciarello] • QCALT - W+ Scint Tiles w SiPMs (Quads) • CCALT - LYSO+APDs (Low-beta) • LET QCALT March 2nd 2017 - A. Di Cicco - INSTR17 3
Th The KLOE-2 2 experiment KLOE-2 is presently taking data at DA 𝜚 NE 𝜚 -factory e + e - collider at √s = 1019.4 MeV [Talk by D. Domenici] Physics Program [EPJ C68 (2010)] DC • K S , η, η S rare decays IT • γγ physics • Quantum Interferometry HET 11 m from IP • Dark Photon searches ECAL Calorimeter System ECAL - Pb/Scint Fibers w PMTs • CCALT LET - LYSO+SiPMs • HET - Scint+PMTs [Talk by F. Curciarello] • QCALT - W+ Scint Tiles w SiPMs (Quads) • CCALT - LYSO+APDs (Low-beta) • LET Tracking System DC – 3.7x4 m 2 He:Iso 90:10 gas mixture • IT – 4 cylindrical GEM tracking devices • Superconductive Magnet 0.52 T axial magnetic field • QCALT March 2nd 2017 - A. Di Cicco - INSTR17 4
Th The Inner Tracker of KLOE-2 o Improve VTX reconstruction at IP The 4 cylindrical-GEM layers of the IT o First batch ever of GEM foils produced with a 41 cm 36 cm 31 cm 26 cm single-mask etching developed by CERN-TE-MPE-EM for large area foils o 70 cm active length Inner Tracker o 650 µm strips two-view readout o 25k channels GASTONE FEE [NIM A 732 (2013)] o 1.6k HV channels o FEE DAQ system [JINST 08 T04004 (2013)] o 1200 gas gain o 2% X 0 material budget March 2nd 2017 - A. Di Cicco - INSTR17 5
Th The Inner Tracker of KLOE-2 o Improve VTX reconstruction at IP The 4 cylindrical-GEM layers of the IT o First batch ever of GEM foils produced with a 41 cm 36 cm 31 cm 26 cm single-mask etching developed by CERN-TE-MPE-EM for large area foils o 70 cm active length Inner Tracker o 650 µm strips two-view readout o 25k channels GASTONE FEE [NIM A 732 (2013)] Each layer is a o 1.6k HV channels triple-GEM detector o FEE DAQ system [JINST 08 T04004 (2013)] with 3/2/2/2 mm o 1200 gas gain layout o 2% X 0 material budget March 2nd 2017 - A. Di Cicco - INSTR17 6
Th The Inner Tracker of KLOE-2 o Improve VTX reconstruction at IP The 4 cylindrical-GEM layers of the IT o First batch ever of GEM foils produced with a 41 cm 36 cm 31 cm 26 cm single-mask etching developed by CERN-TE-MPE-EM for large area foils o 70 cm active length Inner Tracker o 650 µm strips two-view readout o 25k channels GASTONE FEE [NIM A 732 (2013)] Each layer is a o 1.6k HV channels triple-GEM detector o FEE DAQ system [JINST 08 T04004 (2013)] with 3/2/2/2 mm o 1200 gas gain layout o 2% X 0 material budget Kapton/Copper flexible multilayer readout circuit 650µm built at CERN TE-MPE-EM, 300 µm tot thickness X-view : longitudinal strips ~ 30° V-view : connection of pads through conductive 600µm vias and common backplane March 2nd 2017 - A. Di Cicco - INSTR17 7
IT IT Operation Optimization Cosmic-ray muon DC tracks extrapolated to IT • Take closest reconstructed IT cluster • to expected position from DC track 26 cm Dips in occupancy due to Cosmic-ray muons GEM foil micro-sector structure 1.0 Efficiency ε 10% improvement with E IND =6kV/cm 0.9 2 2 χ χ / ndf / ndf 3.855 / 2 3.855 / 2 0.8 p0 p0 0.9771 0.9771 0.007135 0.007135 ± ± p1 p1 -0.5051 -0.5051 0.04709 0.04709 ± ± Efficiency X-view 0.7 p2 p2 0.07 0.07 0 0 ± ± Layer#1 p3 p3 0.0004 0.0004 0 0 ± ± E IND = 6 kV/cm 0.6 p4 p4 -10 -10 ± ± 0 0 0.5 5000 10000 15000 20000 Gain ε = 94% single-view @ Gain = 12000 Good compromise between IT clustering efficiency and detector operation with colliding beams March 2nd 2017 - A. Di Cicco - INSTR17 8
IT IT Operation Optimization Cosmic-ray muon DC tracks extrapolated to IT Bhabha scattering events selected using • • Take closest reconstructed IT cluster DC track information • to expected position from DC track 26 cm Bhabha scattering Efficiency vs z Dips in occupancy due to Cosmic-ray muons GEM foil micro-sector structure 1.0 Efficiency ε 10% improvement with E IND =6kV/cm 0.9 2 2 χ χ / ndf / ndf 3.855 / 2 3.855 / 2 0.8 p0 p0 0.9771 0.9771 0.007135 0.007135 ± ± p1 p1 -0.5051 -0.5051 0.04709 0.04709 ± ± Efficiency X-view 0.7 p2 p2 0.07 0.07 0 0 ± ± Layer#1 p3 p3 0.0004 0.0004 0 0 ± ± E IND = 6 kV/cm 0.6 p4 p4 -10 -10 ± ± 0 0 0.5 5000 10000 15000 20000 Gain z (cm) ε = 94% single-view @ Gain = 12000 Preliminary two-view efficiency measurement Good compromise between IT clustering efficiency with IT operating during collisions and detector operation with colliding beams in agreement with cosmic-ray data analysis March 2nd 2017 - A. Di Cicco - INSTR17 9
IT IT Operation with Co Collisions Online monitoring – IT operations with collisions Old HV scheme : 7 independent channels referred to ground, 26 cm possible discharge propagation among GEM stages when current saturates on one electrode New HV scheme : GEM voltages 7 independent floating channels, other decrease if voltages HV CAEN A1515CG successfully tested and current is unchanged above limit installed in Sep 2016 on all layers for safer (5000 nA) operation HV CAEN A1515CG Test on Layer#3 Single voltage adjustment allowed March 2nd 2017 - A. Di Cicco - INSTR17 10
IT IT Operation with Co Collisions Online monitoring – IT operations with collisions Old HV scheme : 7 independent channels referred to ground, 26 cm possible discharge propagation among GEM stages when current saturates on one electrode New HV scheme : GEM voltages 7 independent floating channels, other decrease if voltages HV CAEN A1515CG successfully tested and current is unchanged above limit installed in Sep 2016 on all layers for safer (5000 nA) operation HV CAEN A1515CG Test on Layer#3 Single voltage adjustment allowed Online monitoring – IT current of innermost layer IT L1 Current (nA) Current spikes over threshold may occur at beam injections without discharges propagating through GEM stages time March 2nd 2017 - A. Di Cicco - INSTR17 11
IT IT Calibration Strategy 1. NON-RADIAL TRACKS The angle 2. MAGNETIC FIELD 0.52 T B-field formed by a track and the radialE- orthogonalto GEM stages E-fields: field direction introduces shift & shift and larger spread of the 26 cm spread of the e - cloud electron cloud March 2nd 2017 - A. Di Cicco - INSTR17 12
IT IT Calibration Strategy 1. NON-RADIAL TRACKS The angle 2. MAGNETIC FIELD 0.52 T B-field formed by a track and the radialE- orthogonalto GEM stages E-fields: field direction introduces shift & shift and larger spread of the 26 cm spread of the e - cloud electron cloud Cosmic-ray muon data acquired with B-field OFF � Calibration of Non-radial track effect � Select DC tracks crossing IT at 2 points � Shifts and rotations to align the IT March 2nd 2017 - A. Di Cicco - INSTR17 13
IT IT Calibration Strategy 1. NON-RADIAL TRACKS The angle 2. MAGNETIC FIELD 0.52 T B-field formed by a track and the radialE- orthogonalto GEM stages E-fields: field direction introduces shift & shift and larger spread of the 26 cm spread of the e - cloud electron cloud Cosmic-ray muon data acquired with B-field OFF � Calibration of Non-radial track effect � Select DC tracks crossing IT at 2 points � Shifts and rotations to align the IT Cosmic-ray muon data acquired with B-field ON � Calibration of Non-Radial track & B-field effects � Corrections, Shifts and rotations from B-field OFF sample March 2nd 2017 - A. Di Cicco - INSTR17 14
IT IT Calibration Strategy 1. NON-RADIAL TRACKS The angle 2. MAGNETIC FIELD 0.52 T B-field formed by a track and the radialE- orthogonalto GEM stages E-fields: field direction introduces shift & shift and larger spread of the 26 cm spread of the e - cloud electron cloud Cosmic-ray muon data acquired with B-field OFF � Calibration of Non-radial track effect � Select DC tracks crossing IT at 2 points � Shifts and rotations to align the IT Cosmic-ray muon data acquired with B-field ON � Calibration of Non-Radial track & B-field effects � Corrections, Shifts and rotations from B-field OFF sample Bhabha scattering events � Check calibration of Non-radial track & B-field effects � Corrections , Shifts and rotations from cosmic-ray muon data analysis with B-field ON sample March 2nd 2017 - A. Di Cicco - INSTR17 15
Recommend
More recommend
