BRAN at IR2 and IR8: status, commissioning and operation Enrico Bravin AB-BI Joint LHC Machine-Experiments Workshop on Very Forward Detectors 25 January 2007

Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 2 Introduction  Contrary to ATLAS and CMS where luminosity should be maximized, LHC-b and ALICE require optimal luminosity levels which are substantially lower than cm -2 s -1  This reduces the constraints on radiation hardness for the collision rate monitors at IP2 and IP8.  Using solid state CdTe detectors instead of the ionization chambers used in the other two IRs  As there is no TAN a converter/absorber block has to be installed in front of the detector (~20cm of copper)

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 3 Monitors principle

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 4 Status of the CdTe Detectors  The monitors consist of one box containing 10 CdTe disks with 16mm (14mm active) 350m thick disposed on two rows.  The monitors are the result of a collaboration between CERN and CEA-LETI Grenoble. LETI is producing and delivering the full monitors.  First full module delivered end of November 2006  Remaining 3 modules will be delivered by April 2007

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 5 CdTe monitors CdTe disks Contact pins 94 mm

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 6 Mechanics  Detectors will be mounted on fixed support  At ALICE the converter block has to be removed during ions runs.  Two different converter thicknesses will be better at LHC-b (low/high luminosity) to reduce dose to the monitor  Converter/Absorber in front of detector need support with 2 positions: Converter 1 / Converter LHC-b Converter IN / Converter ALICE

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 7 Detector/Converter Support status  Design finished  Parts produced  One support already assembled  3 more to be assembled  The first will be installed soon (IP 8R)

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 8 Support design

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 9 Monitor/Converter Support

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 10 p-p events  DPMJET3 simulation of p-p events (V.T)  a) Simple transport of neutrals in straight path of flight  b) Transport/decay/ineractions using FLUKA (Vadim Talanov) (Not yet ready)  Surprise: at 900GeV c.m. the number of events sending particles in the detectors is very small ~1% (at 14TeV ~100%)  FLUKA simulations of shower in converter/detector (E.Bravin, T.Lefevre)

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 11 Energy deposition 100GeV

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 12 p-p Events vs. Background I b, N b Beam halo scraping I b, N b Beam –Gas collisions I b 2, N b, Lp-p inelastic collisions Rate [s- 1 ] L= GeV 1 x Rate [s- 1 ] L= TeV 2808 x ScalingProcess

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 13 Signal level (CdTe)  Consider only neutral particles (,n) > 100 GeV (most particles are above this threshold)  dE/dx in copper  1GeV/cm  This corresponds to a signal v det  2mV  No need for special low noise Front- End electronics

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 14 Front-End electronics (CdTe)  Expected signal is rather big  Use existing 200MHz linear amplifiers  Original design by M.Gasior for the BPM of CTF3, then modified for the BLM of CTF3.  Simple, robust, “rad-hard” and tested  Need just to increase number of channels and add BIAS (300V)

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 15 F.E. Amplifier  Design adapted  Production is currently underway (16 boxes of 5ch. each)  Expected mid February

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 16 Acquisition chain

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 17 Analog signal processing  Each detector outputs 10 signals (1 per each CdTe disk)  Need to calculate Sum, Delta_H, Delta_V, Hit (Sum > Threshold) and Coincidence  2 DAQ racks per IP (300m apart) use optical fiber to carry Hit pulse from one to the other (for coincidence detection)  Threshold should be programmable  Everything done within one VME module

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 18 Analog processing (cont’d)  Design almost finished (S.Burger)  Design includes an FPGA for VME communication and Threshold control  Will integrate counting (bunch by bunch) in the FPGA  Modules expected Q2 2007

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 19 Signal acquisition  Acquisition (counting) done in the analog processing board  Sum signal acquired using the DAB+FBCT mezzanine (BI existing system), Bunch by Bunch  Delta signals could be acquired the same way, probably not used for first run (no crossing angle)

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 20 Data processing  Data (average and b-b rates) read through VME bus by CPU  FESA class will calculate and publish final values to users  Display applications for control room  Data exchange server dispatches measured values to the experiments

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 21 Detectors test and calibration  Each CdTe disk has been tested and qualified by LETI before assembly  Need to put detectors in test beam to verify correct functioning of the assembly and to calibrate transverse shower position measurement  Beam tests currently being planned

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 22 Detector commissioning  Not much can be tested without beam  After installation electrical tests will be performed by sending pulses on HV (BIAS) input and observing output signals  Possibility of testing detectors using a pulsed laser under investigation  Real commissioning will happen once the beam is there  Racks are not accessible during LHC operation, will use remote controlled scopes for direct signal observation during commissioning

25 January 2007Joint LHC Machine-Experiments Workshop on Very Forward Detectors - E. Bravin 23 Summary  The hardware and software needed for the monitors is underway and no major issue exists at the moment  At 900 GeV c.m. the number of hits in the detectors is very low  since only 1% of events generate a hit coincidence can not be used  No data exists (?) about the background situation. Measuring collision rates for Run 1 will be very difficult if possible at all.  Run 1 will anyway be useful in understanding the monitors for the future