1. March 2004LCWS Stanford Instrumentation of the Very Forward Region of a Linear Collider Detector Wolfgang Lohmann, DESY

2. -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0 11.522.533.5 4 QD0 Inst. Mask HCAL ECALECAL YOKE W W 46mrad 113mrad Support Tube Pair- LuMon BeamPipe LowZ Mask Exit radius 2cm @ 3.5m W W 5 Tesla SiD Forward Masking, Calorimetry & Tracking, T. Maruyama Simulation studies on several designs Used by H. Yamamoto

3. Functions of the very Forward Detectors Fast Beam Diagnostics Detection of Electrons and Photons at very low angle – extend hermeticity (Important for Searches ) Shielding of the inner Detectors IP VTX Measurement of the Luminosity with precision O(<10 -3 ) LumiCal BeamCal FTD L* = 4m 300 cm LumiCal: 26 <  < 82 mrad BeamCal: 4 <  < 28 mrad PhotoCal: 100 <  < 400  rad

4. Measurement of the Luminosity Goal: <10 -3 Precision Gauge Process: Technology: Si-W Sandwich Calorimeter MC Simulations e + e - e + e - (  ) Optimisation of Shape and Segmentation, Key Requirements on the Design Physics Case: Giga-Z, Two Fermion Cross Sections at High Energy, e + e - W + W -

5. Inner Radius of Cal.: < 1-4 μm Distance between Cals.: < 60 μm Radial beam position: < 0.7 mm Requirements on Alignment and mechanical Precision (rough Estimate) LumiCal IP < 4 μm  < 0.7 mm Requirements on the Mechanical Design

6. Decouple sensor frame from absorber frame Sensor carriers Absorber carriers Concept for the Mechanical Frame

7. Jagiellonian Univ. Cracow Photonics Group reconstruction of the laser spot (x,y) position on CCD camera CCD camera, He-Ne red laser, Laser translated in 50  m steps Laser Alignment Test

8.  Constant value 0.11e-3 rad 0.13e-3 rad  30 layers 15 rings 20 rings 10 rings  4 layers 15 layers 11 layers 10 rings Performance Simulations for e + e - e + e - (  ) Event selection: acceptance, energy balance, azimuthal and angular symmetry. Simulation: Bhwide(Bhabha)+CIRCE(Beamstrahlung)+beamspread

9. Determination of the Acceptance region Out In  Eout-Ein  Eout+Ein P = 1 ring 2 rings 3 rings P

10. ΔE~0.31 √ E Determination of shower Coordinates Strip version

11. Fast Beam Diagnostics e+e+ e-e- 15000 e + e - per BX 10 – 20 TeV 10 MGy per year Rad. hard sensors Technologies: Diamond-W Sandwich Scintillator Crystals e + e - Pairs from Beamstrahlung are deflected into the BeamCal GeV Gas Ionisation Chamber direct Photons for  < 200  rad

12. Heavy crystals W-Diamond sandwich sensor Space for electronics Schematic Views

13. first radial moment thrust value total energy angular spread L/R, U/D F/B asymmetries Observables Quantity Nominal Value Precision xx 553 nm1.2 nm yy 5.0 nm0.1 nm zz 300  m4.3  m yy 00.4 nm Beam Parameter Determination with BeamCal

14. nominal setting (550 nm x 5 nm)  >100m IP L/R, U/D F/B asymmetries of energy in the angular tails Quantity Nominal Value Precision xx 553 nm4.2 nm zz 300  m7.5  m yy 00.2 nm Heavy gas ionisation Calorimeter and with PhotoCal Photons from Beamstrahlung

15. Detection of High Energy Electrons and Photons √s = 500 GeV Single Electrons of 50, 100 and 250 GeV, detection efficiency as a function of R Detection efficiency as a function of the electron energy for different positions Message: Electrons can be detected!

16. Includes seismic motions, Delay of Beam Feedback System, Lumi Optimisation etc. (G. White) Efficiency to identify energetic electrons and photons (E > 200 GeV) Fake rate √s = 500 GeV Realistic beam simulation

17. Sensor prototyping, Crystals Light Yield from direct coupling Similar results for lead glass Crystals (Cerenkov light !) and using a fibre ~ 15 % Compared with GEANT4 Simulation, good agreement

18. Sensor prototyping, Diamonds  ADC Diamond (+ PA) Scint.+PMT& signal gate May,August/2004 test beams CERN PS Hadron beam – 3,5 GeV 2 operation modes: Slow extraction ~10 5- 10 6 / s fast extraction ~10 5 -10 7 / ~10ns (Wide range intensities) Diamond samples (CVD): - Freiburg - GPI (Moscow) - Element6 Pm1&2 Pads

19. Linearity Studies with High Intensities Response to mip Diamond Sensor Performance Pm-Pm Pm-Pads Pm-Pad1 Pm-Pad2 Pm-Pad3 Pm-Pad4

20. Summary A lot of activity in simulations/design studies…… Concept for a Luminometer is progressing Studies with sensors started- needs more effort High energy electron detection down to small polar angles is feasible with compact and fine segmented calorimeters Prototype tests mandatory Remarks The instrumentation of the forward region is independent of the detector concept, but it depends on the crossing angle scheme

21. Shower in LAT (TDR design) Shower LEAKAGE in old (TDR) and new LumiCal design Shower in LumiCal (new design)

22. Diamond performance as function of the absorbed dose Linearity of a heavy gas calorimeter (IHEP testbeam)

23. Comparison Sampling Heavy Crystal Comparison Sampling Heavy Crystal Comparison 500 GeV - 1TeV