NLC - The Next Linear Collider Project Discussion Detector Multiplicities & Timing Requirements Warm vs. Cold Tom Markiewicz SLAC ALCPG SLAC 8 January 2004

Tom Markiewicz NLC - The Next Linear Collider Project Backgrounds and IR Layouts Incoherent production of e+e- pairs. –# pairs scales with luminosity and is ~equal for both designs. –Detector occupancies depend on machine bunch structure and relevant readout time –IR Designs are similar in the use of tungsten shielding, instrumented masks, and low Z material –GEANT and FLUKA based simulations indicated that in both cases occupancies are acceptable TESLA-500JLC/NLC-500 N 2.0 x x xx 550 nm243 nm yy 5 nm3 nm zz 300  m110  m

Tom Markiewicz NLC - The Next Linear Collider Project NLC/TESLA Beam-Beam Comparison NLC500TESLA500 DyDy 1425  nn bb 4.6%3.2% HDHD # pairs/bunch 49,000130,000 _pair e4.1 GeV2.8 GeV #pairs/ sec1.1E91.8E9 #pairs/ Lum5.5 fm fm 2 Larger  z for TESLA More time for disruption larger luminosity enhancement more sensitivity to jitter Lower charge density lower energy photons

Tom Markiewicz NLC - The Next Linear Collider Project Detector Occupancies from e+e- 500 GeV fcn(bunch structure, integration time) DetectorPer bunchR. O.Eff #B OccupancyComment VXD-L136E-3/mm 2 50  s1485.3/ mm 2 1.5cm, 4T VXD-L23.1E-3/mm  s / mm 2 2.6cm, 4T TPC1336 , 5trks55  s160Few per mil Barrel ECAL 1176 , 0.63GeV150 ns GeV101  >3MeV Endcap ECAL1176 , 1.29GeV150 ns GeV91  >3MeV VXD-L138E-3/mm 2 8 ms1927.2/ mm 2 1.2cm, 3T VXD-L23.1E-3/mm 2 8 ms1920.6/ mm 2 2.4cm, 3T TPC1377 , ?trks8 ms192 “Few per mil” Needs Study Barrel ECAL 547 , 0.73 GeV 8 ms GeV Needs Study Endcap ECAL597 , 0.9 GeV 8 ms GeV Needs Study TESLATESLA NLCNLC TESLA=TDR; NLC=Snowmass 2001