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The interaction region and BEAST II

The interaction region and BEAST II. S. Tanaka (KEK). KEK VXD group S.Tanaka (VXD assembly coordinator: BP, shields, PXD liaison) H. Nakayama(BG simulation, BEASTII+BG monitors) K.Hara(SVD group leader) T.Tsuboyama (SVD) K.Nakamura (SVD)

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The interaction region and BEAST II

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  1. The interaction region and BEAST II S. Tanaka (KEK)

  2. KEK VXD group S.Tanaka (VXD assembly coordinator: BP, shields, PXD liaison) H. Nakayama(BG simulation, BEASTII+BG monitors) K.Hara(SVD group leader) T.Tsuboyama (SVD) K.Nakamura (SVD) T. Kohriki (mechanics designer: BP, CDC, TOP. ARICH) S.Koike (VXD mechanics designer) N.Sato(SVD mechanics engineer) K.Kanazawa (machine group: BP design)

  3. SuperKEKB (KEKB upgrade) e- (7 GeV) • BoostedU(4s) production by asymmetric e+e- collider • √s ~10.58GeV • Target luminosity: 8・1035cm-2s-1 • 40 times higher than KEKB • Nano beam scheme e+ (4 GeV) e- (7 GeV) e+ (4 GeV) Y(4S) dz~cbgtB Y(4S) ~200mm (Belle) ~130mm (Belle II) SuperKEKBbg=0.28 : e-(7GeV), e+ (4GeV) KEKB bg=0.42: e-(8GeV), e+ (3.5GeV) HER (8 GeV -> 7GeV): • Lower emittancelinac beam ∝ 1/E 2 • Lower Synchrotron radiation loss LER (3.5 GeV -> 4GeV): • Longer Touschek lifetime ∝ E 3 • Intra-beam scattering effect to emittance

  4. Nano beam scheme Lorentz factor Beam current Beam-beam parameter correction coefficient bfunction: aperture of beam s: Beam size ×20 ×2 DEPFET pixels as a vertex detector for the Belle II experiment

  5. 83 mrad Effective bunch length Vertical beam size KEKB superKEKB

  6. BelleII Design 8m×8m×8m ～1500ton Magnetic field： 1.5T

  7. DSSD strip layers pixel layers Vertex detector upgrade Belle II: Pixels (2 layers) + SVD (4 layers) Belle: SVD (4 layers) • Inner most layer: 2cm (Belle) -> 1.4cm (BelleII) • Outer coverage: 8cm (Belle) -> 13.5cm (BelleII) DEPFET Pixel Mockup Silicon Vertex Detector Beam pipe inner radius: 10mm (15mm : Belle)

  8. Belle II pixel detector • Belle II environment: • - Occupancy : 0.4 hits/mm2/s • - average particle momentum: ~500 MeV • - Radiation tolerance: > 1Mrad/year • - Acceptance: 170-1550 • - Higher vertex resolution -> lower material budget • (~0.21 % X0 for layer) To achieve 10 mm spatial resolution , pixel size is determined as ~50 x 50 mm 2 (Since Lorentz boost factor on Belle II is 67 % of Belle case, vertex resolution should be better according to this )

  9. PXD readout Two layers R=14 mm 8 ladders, R = 22mm 12 ladders 100 kB/ev. 1 MB/ev. 256 lines 1st:50 x 55 µm² 2nd:50 x 70 µm² Event Builder 512 lines 1st:50 x 60 µm² 2nd: 50 x 85 µm² Data reduction by RoI scheme 80Gbit/s 4 Gbit/s by Zero suppression DEPFET pixels as a vertex detector for the Belle II experiment

  10. Performance • Beam test by 120 GeV pion beam • Position resolution =8mm • S/N=30~40 Total Cluster=1 Cluster=2 6 mm gate length 4GeV electron beam test of VXD (2 PXD+ 4 SVD) with mini Belle II DAQ is scheduled in Jan. 2015. 4 mm gate length (Baseline) (gq ~ 1/L 3/2: L is gate length)

  11. Injection BG  Continuous injection from 2004 The injection BG is vetoed by revolution signal from machine. (The beam life time is ~600s for LER by Touschek effect) PXD case : to avoid injection hits Gated operation Charges from background drift directly to clear gate Normal operation: Signal charge drifts into internal gate

  12. BG sources and Radiation tolerance • Radiation environment • 4-fermion final state QED process • Touschek effect • Beam-gas interactions • Synchrotron radiation • Radiative Bhabha scattering Occupancy by each BG source: PXD case Synchrotron radiation(very preliminary): 0.14 % (one ladder in horizontal plane: ~1.8%) Still under investigation

  13. BG reduction

  14. VXD mechanics

  15. Overview of beam pipe design Ti Ta Ti Be Ta All of connection steps have been tested before production Inner design: (Machine group) Outer design: (Belle group)

  16. IP mechanics Beryllium PXD mount block

  17. VXD assembly steps Those procedure will be validated on BEAST assembly

  18. Current VXD design Koike BWD PXD service is just mirror image of FWD VXD mockup

  19. VXD mechanics sub-parts preparation Milestone: 2014 Autumn SVD ladder mount test start (2015 Jan. start) 2015 Summer VXD assembly 2016 Feb. BEAST (Belle II w/o VXD) Two sets of Beam pipes, heavy metal shields and CFRP supports Schedule tight Rough estimation of production period and cost have already done for each products • Producing beam pipes: • ~2014 Mar. Beam pipe for BEAST (2014 Jul. on global schedule) • ~2015 Mar. Beam pipe for physics run (2015 Jul. on global schedule) • Heavy metal shields • ~2014 Mar. Shields for BEAST • ~2015 Mar. Shields for physics run • End-flange, CFRP support cone, CFRP outer cover • ~2014 Mar. one of support parts (for physics run) • ~2014 summer second set production (for back-up, BEAST) • Production takes 2 month

  20. http://www.phys.hawaii.edu/~sevahsen/tdr_beast.pdf BEAST

  21. S.Vahsen (Hawaii)

  22. BEAST Setup Design is ongoing. Phase II Belle is roll –in position. No VXD detectors Phase I Main task is vacuum scrubbing of beam pipe. Belle will not roll-in

  23. Sensor activities • SR measurement by SDD, diamond sensor • Radiation monitor and deciding beam abort • PIN Diode Radiation Dose Monitors • BGO Crystal Luminosity Monitor • Neutron detection by MicroTPC • Thermal neutron detector (He-3 gas chamber)

  24. BEAST phase 2 (2016 Feb.) • DAQ commissioning • CDC, TOP, ARICH, ECL,KLM (some test ladders of SVD+PXD?) • BG monitoring • Measuring BG at each sub-detector position -> NSM2, EPICS(machine) • Measuring Injection noise (veto timing study) • Setting abort signal to machine for safety VXD operation • Hardwired optical line to machine • Movable mask control study • Measuring each BG component • Optimizing mask control procedure • Cooling test of VXD area (option)

  25. Belle/KEKB communication BELLE-1 KEKB control Belle solenoid field sensor, power outage Belle_abort Beam current/ lifetime measurement BEAM abort system Hard-wired Belle_abort SVD BG monitor (PIN,RADFET,RTD) Injection_inhibit PIN diode Injection system Inj. eff. Injection_inhibit Beam loss monitors @ collimators HV control CDC leak current CDC current alarm (“beep sounds”) CDC ECL BG level CATV ECL BG monitor CATV display (oscilloscope monitor) TOF single rate, Injection veto TRG Collimator control (BCG) Data Quality Monitor, Uehara-monitor, (NSM) KEKBlog (EPICS) Luminosity, z-vertex, Sub-detector BG levels, etc.. Conceptual discussion is just starting now

  26. Thank you!

  27. Snapshot of VXD mechanics preparation • VXD assembly procedure has almost defined • Beam pipe production (2012 Oct- ) • 1st pipe for BEAST will be produced by March 2014. • (2nd for physics: ready in March 2015) • All of production tool have prepared and mock-up test finished • Heavy metal part production (2013 Oct-, final 2D design before Dec. ) • 1st production for BEAST will be done by March. • 2nd production for physics run is schedule in next year. Then KEK-MPI group is keep discussing to optimize fine assembly work. • CFRP part production (2013 Oct-) • 1st production (for physics) should finished in this fiscal year (takes 3month after order) • End-flange production (Al or SUS) • 1st production (for physics) should finished in this fiscal year (takes 2 month) • Need optimization of some function for service (fixing or thermal isolation ) • BP+HM+PXD assembly (schedule in 2015 Aug) • Assembly procedure have prepared including service work • Service space • Space requirement by each service have almost finalized. • Discussion of service work procedure is ongoing

  28. KEKB-Belle interface

  29. KEKB operation using Belle information • Belle information is used by KEKB for • abort the beam(s) • stop/resume injection • optics knob tuning (by Kekb Commissioning Group) • open/close collimator (by Belle Commissioning Group) • etc..

  30. BelleKEKB • BELLE_ABORT • Issued by SVD hardware/software abort system • Belle solenoid field monitor, power outage • INJECTION_INHIBIT • Issued by SVD software abort system, HV system during ramp. Up • CDC dark current? • “CDC current limiter beep sounds” in KEKB control room • Display in KEKB control room, showing video of oscilloscope monitor • Showing timing structures, rather than trend • TOF single rate, ECL BG monitor (pure CSI), SVD BG monitor(PIN diode) • injection veto signal provided • Information sent from Belle-NSM to KEKBlog:EPICS • Rather slow update (<1Hz , or slower) • z-vertex, luminosity, sub-detector BG levels, etc…

  31. KEKBBelle • TRG system receives following information from KEKB • RF clock • Revolutional signal • Injection signal for generating injection veto • ~50us prior to injection

  32. BELLE-1 KEKB control Belle solenoid field sensor, power outage Belle_abort Beam current/ lifetime measurement BEAM abort system Hard-wired Belle_abort SVD BG monitor (PIN,RADFET,RTD) Injection_inhibit PIN diode Injection system Inj. eff. Injection_inhibit Beam loss monitors @ collimators HV control CDC leak current CDC current alarm (“beep sounds”) CDC ECL BG level CATV ECL BG monitor CATV display (oscilloscope monitor) TOF single rate, Injection veto TRG Collimator control (BCG) Data Quality Monitor, Uehara-monitor, (NSM) KEKBlog (EPICS) Luminosity, z-vertex, Sub-detector BG levels, etc..

  33. Info. used for KEKB collimator control <~1Hz At SuperKEKB, all information should be provided to the collimator control algorithm.Those information should be summarized and shown on BCG monitor.

  34. What’s new at SuperKEKB/Belle-II Not only VXD but also TOP might be killed. Loss at |s|~1m is also dangerous. • Beam_abort • Issued by PXD, SVD, IR loss monitor (, and other sub-detectors?) • Injection_inhibit • Issued by PXD, SVD, IR loss monitor (, and other sub-detectors?) • Collimator control • (Semi-)automatic control algorithm? • “Beep sound”, “oscilloscope monitor” are good for human eye/ear, but we also need to provide necessary information (as digital data) to the algorithm • IR loss distribution might tell us which BG source and which collimator to close

  35. Collimator algorithm • Optimization of 20~30 parameters • Asymmetric widths might be needed • Evaluated by: • beam lifetime • IR loss (Should be weighted by loss position) • loss at the final collimator • Required measurements • Beam current, loss monitor at all collimators, IR loss monitor, sub-detector BG level measurements • Quick enough feedback to perform iteration of collimator adjustments (moving 20um takes ~200ms) • Tsukuba-hall radiation level monitor

  36. - For Touschek/Coulomb/RBB BG sensor, above positions are proposed. (6 or 8 sensors in phi direction for each z position) - Type of sensor • Need quick feedback for collimator adjustment (espc. z=+-120cm) • PIN diode? Diamond? Specifications? • Thin plastic scintillator? • Neutron sensor?

  37. IR Service space

  38. Narrowest space between QCS and CDC

  39. PXD+SVD service Latest service space estimation with support structure around VXD is ongoing

  40. PXD and SVD docks SVD and PXD dock space requirements will be taken in CDC design. SVD dock PXD dock

  41. Space request by cooling pipes

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