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Diamond Beam Conditions Monitor for ATLAS (H. Pernegger, CERN). People involved sofar from ATLAS Inner Detector. JSI, Ljubljana G. Kramberger, I. Mandi ć, M. Zavrtanik, V. Cindro, M. Mikuz CERN H. Pernegger Fotec, Wiener Neustadt E. Griesmayer, H. Frais-K ö lbl.
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Diamond Beam Conditions Monitor for ATLAS(H. Pernegger, CERN)
People involved sofar from ATLAS Inner Detector • JSI, Ljubljana • G.Kramberger, I.Mandić, M. Zavrtanik, V. Cindro, M. Mikuz • CERN • H. Pernegger • Fotec, Wiener Neustadt • E. Griesmayer, H. Frais-Kölbl
Part of the ATLAS Radiation Monitoring System • Instantaneous • Beam Condition Monitor – BCM Draft EDMS document ATL-IC-ES-0012 • Integrating – on-line • Total Ionization Dose - TID • Non-Ionizing Energy Loss – NIEL • Thermal Neutrons EDMS document in preparation • Integrating – off-line • TLD – not discussed today
ATLAS BCM goal • Goal of the BCM detector system inside the ATLAS Inner Detector • Monitor normal operation conditions • Measure rate of collision • Measure background rate close to vertex • Protection • Detect early signs of beam instabilities • Issue warning and alarm signals for equipment protect • Input to ATLAS Detector Safety system and LHC beam abort
ATLAS BCM - beam loss scenarios Simulations of beam orbits with wrong magnet settings (D. Bogdan) exhibit scenarios with beam scrapping TAS Time constants of D1 & D2 dipoles large Can abort beam if detected early
12ns Time difference ATLAS BCM during normal running • Time-Of-Flight measurement to distinguish collisions from back ground Need to measure single MIPs fast!
Timing of Hits on Collimators 2x4 detector stations, symmetric in z TAS events: Δt = 2z/c Interactions: Δt = 0, 25, … ns
CMS simulations of 7 TeV p on TAS From M. Huhtinen Zoom on ID ~ MIPs/cm2 per proton (ATLAS simulations by M Schupe in progress)
ATLAS BCM requirements • Distinguish TAS events from interaction events • Installation at Dt = 12.5 ns -› Dz = 3.75 m • Rise-time < 1 ns • Pulse-width < 3 ns • Base-line restoration < 10 ns • Single MIP sensitivity • S/N for MIP’s 10:1 before irradiation
BCM mounting points BCM installation in ATLAS Pixel Support Pixel support tube: mid crucifix at z = 1838 mm, r > 100 mm Detectors to be mounted at 45 degrees Cables: 4 mm coax up to PP1, 8 mm to USA15 HV, LV: custom Kapton insulated shielded TP Routing through single pixel phi sector/side
Detector 90Sr source test at CERN • Diamond detector • w =470 µm, CCD ~ 200 µm • HV Bias 1000 V • Different versions of FE electronics from Fotec • 500Mhz (40 dB) (2 stages) • 1 Ghz (60 dB) (3 stages) • LeCroy 1 GHz scope 90Sr source Pb collimator Diamond on support Scintillator
Readout for characterization with fast current amplifier • Based on LabView
Diamond + electronics Tests in Testbeam • MIP signal (testbeam & Sr90 source) • after 16m of cable • perpendicular to beam, double diamond assembly • Rise time 900ps, FWHM = 2.1ns SNR = 7.3:1
Preliminary Detector & Electronics Tests: Sr90 • MIP signal in CDS 113 • Perpendicular • Tested with source in Lab • Results: • “ENC” = 1400 e- • SNR = 5.4:1
Amplifier radiation test in Ljubljana Tested 1 stage of 1 GHz amplifier (20dB) ( test of 500MHz just started) Bi-polar InGaP transistor Irradiated to Φeq = 1, 5, 10 x 1014 n/cm2 in reactor Verdict: Amplifier still usable after 1015 n/cm2
BCM Logic Scheme ADC-> Intensity Warning/Alarms TDC->TOF
ATLAS BCM Next steps • Finalizing design of FE-end part • Continue with diamonds back-to-back assembly & amplifier irradiation • Finalize required diamond material parameters • Optimize amplifier design (S/N 10:1) • Started to look at Integration aspects • Mounting of detector + FE electronics • Design of readout logic