Diamond Beam Conditions Monitor for ATLAS H Pernegger

Diamond Beam Conditions Monitor for ATLAS (H. Pernegger, CERN) H. Pernegger, CERN, RD 42 coll. Meeting May 2004

People involved sofar from ATLAS Inner Detector z JSI, Ljubljana u G. Kramberger, I. Mandić, M. Zavrtanik, V. Cindro, M. Mikuz z CERN u H. Pernegger z Fotec, Wiener Neustadt u E. Griesmayer, H. Frais-Kölbl H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Part of the ATLAS Radiation Monitoring System z Instantaneous u Beam Condition Monitor – BCM Draft EDMS document ATL-IC-ES-0012 z Integrating – on-line u Total Ionization Dose - TID u Non-Ionizing Energy Loss – NIEL u Thermal Neutrons EDMS document in preparation z Integrating – off-line u TLD – not discussed today H. Pernegger, CERN, RD 42 coll. Meeting May 2004

ATLAS BCM goal z Goal of the BCM detector system inside the ATLAS Inner Detector z Monitor normal operation conditions u Measure rate of collision u Measure background rate close to vertex z Protection u Detect early signs of beam instabilities u Issue warning and alarm signals for equipment protect u Input to ATLAS Detector Safety system and LHC beam abort H. Pernegger, CERN, RD 42 coll. Meeting May 2004

ATLAS BCM - beam loss scenarios Simulations of beam orbits with wrong magnet settings (D. Bogdan) exhibit scenarios with beam scrapping TAS Time constants of D 1 & D 2 dipoles large Can abort beam if detected early H. Pernegger, CERN, RD 42 coll. Meeting May 2004

ATLAS BCM during normal running z Time-Of-Flight measurement to distinguish collisions from back ground 12 ns Time difference Need to measure single MIPs fast! H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Timing of Hits on Collimators 2 x 4 detector stations, symmetric in z TAS events: Δt = 2 z/c Interactions: Δt = 0, 25, … ns H. Pernegger, CERN, RD 42 coll. Meeting May 2004

CMS simulations of 7 Te. V p on TAS From M. Huhtinen Zoom on ID ~ MIPs/cm 2 per proton (ATLAS simulations by M Schupe in progress) H. Pernegger, CERN, RD 42 coll. Meeting May 2004

ATLAS BCM requirements z Distinguish TAS events from interaction events u Installation at Dt = 12. 5 ns -› Dz = 3. 75 m u Rise-time < 1 ns u Pulse-width < 3 ns u Base-line restoration < 10 ns z Single MIP sensitivity u S/N for MIP’s 10: 1 before irradiation H. Pernegger, CERN, RD 42 coll. Meeting May 2004

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 BCM mounting points Cables: 4 mm coax up to PP 1, 8 mm to USA 15 HV, LV: custom Kapton insulated shielded TP Routing through single pixel phi sector/side H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Detector n 90 Sr source test at CERN Diamond detector w =470 µm, CCD ~ 200 µm n. HV Bias 1000 V n n Different versions of FE electronics from Fotec n n n 500 Mhz (40 d. B) (2 stages) 1 Ghz (60 d. B) (3 stages) Le. Croy 1 GHz scope 90 Sr source Pb collimator Diamond on support Scintillator H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Readout for characterization with fast current amplifier z Based on Lab. View H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Diamond + electronics Tests in Testbeam z MIP signal (testbeam & Sr 90 source) u after 16 m of cable u perpendicular to beam, double diamond assembly u Rise time 900 ps, FWHM = 2. 1 ns SNR = 7. 3: 1 H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Preliminary Detector & Electronics Tests: Sr 90 z MIP signal in CDS 113 u Perpendicular u Tested with source in Lab z Results: z “ENC” = 1400 ez SNR = 5. 4: 1 H. Pernegger, CERN, RD 42 coll. Meeting May 2004

Amplifier radiation test in Ljubljana Tested 1 stage of 1 GHz amplifier (20 d. B) ( test of 500 MHz just started) Bi-polar In. Ga. P transistor Irradiated to Φeq = 1, 5, 10 x 1014 n/cm 2 in reactor Verdict: Amplifier still usable after 1015 n/cm 2 H. Pernegger, CERN, RD 42 coll. Meeting May 2004

BCM Logic Scheme ADC-> Intensity Warning/Alarms TDC->TOF H. Pernegger, CERN, RD 42 coll. Meeting May 2004

ATLAS BCM Next steps z Finalizing design of FE-end part u Continue with diamonds back-to-back assembly & amplifier irradiation u Finalize required diamond material parameters u Optimize amplifier design (S/N 10: 1) z Started to look at Integration aspects u Mounting of detector + FE electronics u Design of readout logic H. Pernegger, CERN, RD 42 coll. Meeting May 2004