DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI1 Forward Detectors DCS Forward Detectors (FWD): T0- quartz Cherenkov V0 - plastic scintillator FMD - Si strips Disclaimer: Detector layout and technology details not finalised DCS has not been given much thought ”Small, simple detectors” without very particular requirements - should be able to take many solutions from others

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI2 Forward detectors in ALICE Si-1 Si-2 Si-3 V0-R T0-R

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI3 T0 detector  Precise event timing (  =50ps)  Start detector for ALICE-TOF  Main LVL0 event trigger  Pre-trigger for TRD  Rough on-line vertex determination <1.5 cm  Beam-gas suppression  Output Signals:  T0 = (t r +t l )/2+t d  T0v = t r -t l  T0-L, T0-R  Time and energies  3 levels of sum energy (low, medium, high)

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI4 T0 controls  High voltage:  PM tubes: V  1 supply per counter  24 channels total  Electronics:  48 discriminator channels  24 ADC + 27 TDC channels  parameter loading & monitoring ?  Calibration  laser: parameters & controls?  Trigger circuitry:  parameters & monitoring ?

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI5 V0 detector  Two segmented scintillator hodoscopes on either side of IP Minimum bias trigger: p-p and Pb-Pb Main on-line LVL0 centrality trigger: Pb-Pb Background filter for the dimuon spectrometer Two arm for beam-gas rejection Luminosity control Multiplicity measurement (high occupancy) V0-R Absorber

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI6 V0 layout  V0-L and V0-R: 5 rings each  Rings 1-4: 30° sectors (12)  Ring 5: 15° sectors (24)  Plastic scintillator  Wave-length shifting fibers in groove  Clear optical fibers for light transport (25 m)  Photomultiplier

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI7 V0 controls  High voltage:  PM tubes: V  1 supply per counter  144 channels total  Back-end electronics:  parameters & controls ?  Trigger circuitry:  parameters & monitoring ?

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI8 FMD detector Si2 Si3 Si1

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI9 FMD ring layout 256 Inner: Rin=4.2 cm Rout=17.2 cm Outer: Rin=15.4 cm Rout=28.4 cm 20x2x128= x2x256= Full FMD = 3 inner rings + 3 inner rings + 2 outer rings 2 outer rings

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI10 FMD ring assembly Si FEE Hybrid Support Honeycomb

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI11 FMD Si sensor 256 strips 2  sectors VA-32 pre-amp. chip Connector Daisy chain 256 ch => 25  sec DT

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI12 FMD channels and cables Segments (wafers) Phi sectors Radial strips Hybrids Chips/ Hybrid FE ChipsFE Channels Si 1 inner ,120 Si 1 outer ,120 Si 2 inner ,120 Si 2 outer ,120 Si 3 inner ,120 Total system ,600 Cable function # lines Cable type # cables for inner ring # cables for outer ring FE controls10Shielded twisted pair22 Analog data out1Shielded twisted pair20 FE power4Shielded twisted pair20 (or 10?)20 Bias voltage1Shielded twisted pair ??1020 FMD channel count: FMD cable count:

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI13 FMD controls  High voltage:  bias voltages for Si strips: V  minimum 1 supply per half ring  10 channels total  maximum 1 supply per segment  70 channels total  Low voltage:  power for front end electronics: 5 V ?  1 supply per segment  70 channels total  Front end electronics:  design still very uncertain, only preamp type chosen  options: analog or digital read-out  monitor a few temperatures  down-loading of parameters  Back end electronics: ???

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI14 TPC laser DCS Details:

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI15 TPC laser UV Laser UV Laser: power supply and cooling supplied by Spectron Lasers. Controlled by RS232 to simple DOS program - reprogramming desirable.

DCS meeting, CERN, 17 June 2002Børge Svane Nielsen, NBI16 TPC laser controls  High voltage and cooling of laser:  HV and flash pulse circuit  cooling water circulation unit  control interface to RS232 Rack unit supplied by Spectron Lasers company  Movable optics controls:  picomotor drives (a la stepping motors)  individual motors  Cameras:  CCD cameras for beam position monitoring  8-10 cameras