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TOF Monitor System Status

TOF Monitor System Status. F. Harris U. of Hawaii June 13, 2006. BESIII TOF. Crucial for particle ID Barrel Two layers, 88 counters each layer. 50mm x 60mm x 2500 mm (inner layer). Radius from 810 to 930 mm. BC408 Endcap 88 fan shaped pieces – each end. BC404

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TOF Monitor System Status

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  1. TOF Monitor System Status F. Harris U. of Hawaii June 13, 2006

  2. BESIII TOF Crucial for particle ID • Barrel • Two layers, 88 counters each layer. • 50mm x 60mm x 2500 mm (inner layer). • Radius from 810 to 930 mm. • BC408 • Endcap • 88 fan shaped pieces – each end. • BC404 • Time resolution 1-layer (intrinsic): • Belle: 70 to 80 ps • Beam tests: < 90 ps • Simulation: < 90 ps • K/ separation 2  separation up to 0.9 GeV/c TOF – IHEP TOF electronics - USTC

  3. TOF Calibration System • Hawaii is building a TOF calibration system for BESIII. (Fred Harris, Lucas Nguyen, Steve Olsen, Marc Rosen, and Gary Varner) • Built such systems for both BESII and Belle. • Proposal approved in March 2006. • Important as system monitor and for calibration. BESII system:

  4. BESIII TOF Calibration System • Replace N2-dye laser with Laser Diode (405 or 440 nm)? • Simpler to use and maintain. • Longer lifetime. • ~5 x 107 photons/pulse. • Peak power at low rep. rate: • 405B -- 0.3 W • 405M – 0.6 W (new) PicoQuant GmbH LDH-P

  5. Will it work? CLK Gate.G. Gate.G. NIM NIM TTL TTL attn. attn. LD driver U. Tokyo Measurement System Ushiwaka Dark box Magnet for R5924-70 Dark box for LD fiber diffuser bundle ... LD Ref. PMT in (ADC check) ADC gate stop TDC start

  6. CLK Gate.G. Gate.G. NIM NIM TTL TTL attn. attn. LD driver LD Generation of Laser Pulse When we providebias pulse and trigger pulse, LD generates intensive pulse ! threshold for LD Bias pulse Pulse!! Laser ～550mV ～400mV ～1μs Uses non-standard pulsing system. Safe for BESIII? ～1.8V (max.) Trigger pulse ～10ns

  7. Choice of Laser • LD has many advantages; but is light sufficient with standard pulser? • N2/dye laser has plenty of light and is considerably cheaper. • Tentatively choose N2/dye laser initially. LD may be an upgrade. • Measure efficiency of U. of Tokyo system to determine if LD with standard pulsing has enough light. Gary Varner.

  8. Electronic switch Fiber bundles Light splitter TOF endcap 48 fibers TOF endcap 48 fibers Laser TOF barrel 176 fibers TOF barrel 176 fibers fiber PMT connector TDC start Wrapped with steel tube ADC gate fiber Fiber TOF barrel PMT PMT TOF Monitor System • Use mirror to steer beam – like BESII. • Purchase fiber cable bundles (2 cables).

  9. BESIII TOF Calibration System Use Spiricon Beam Analyzer to analyze beam and design optics – laser into fiber bundle. Optimum design?

  10. Fiber Bundle Cables • Many companies interested: • Ogmentum Inc., Sales and Marketing for FiberLabs • CeramOptec • Romack • Fibertech-optica • Fiberguide Industries • Many choices: (tentative) • Fiber size (100 micron core). • Connectors (FC/PC). • Single fiber jacketing (PVC furcation). • Outer jacketing (SSTL stripwound). • Multiconnector type. • Ferrule.

  11. Fiber Bundle Cables (need 2) 106 (18 spares) cables 7.5 m long with connector on one end and ferrule on other. Barrel TOF Distribution boxes – one side clamps bundle cable; Other side has single feed through connectors 96 fibers with connectors (88 + 8 spares) 2-96 fiber bundles 5.4 m Total length = 21.6 m 8.7 m 9 m 248 fibers (cores + cladding only) with ferrule on end 2 - 28 fiber bundles (24 + 4 spares) EC TOF Total length = 19.7 m Distribution boxes – one side: multi connector Other: single connectors (box 40 mm thick max) 30 (6 spares) cables 2.0 m long with connector on one end and ferrule on other. Cable Dimensions (May 2, 2006)

  12. Fiber Connection to TOF

  13. Cable Routing? Have plan; need to check cable dimensions carefully

  14. Test Setup at UH • Need TOF counter and readout for testing TOF laser calibration system. • Have Belle BC408 TOF counter and 2 BES fine mesh phototubes. • Use cosmic ray telescope. • Have Caen VME TDC with computer to readout. • Caen VME QDC ordered. • Will use BESIII readout when ready.

  15. Test Setup PS711 scalers Delay boxes PS755 Top counter TB TDC trigger Bottom counter TBS 4 ns 50 mv, 28 ns out HV S = 1200 V HV N = 1150 V HV T = 1400 V HV B = 1450 V ~2 counts/min S 40 mv, 30 ns out T N S TOF B PMT

  16. Test Setup – first resultsTelescope near middle of TOF N – B time σ = 0.87 ns S – B time σ = 0.81 ns N – S time σ = 0.61 ns No time walk correction. Need to understand resolution.

  17. Much to do • Complete test setup. • Measure power out and pulse width of UT laser diode. Will laser diode work for us? • Decide on laser. Order by end of summer. • Finalize cable design, connectors, etc. Get quotes. - Order by end of summer. • Install N laser, fiber cables in UH test setup. Test and finalize design. – Summer 2006. • Test cable in Hawaii. Oct/Nov 2006. • Ship everything to IHEP – Dec. 2006. • Begin installation – Jan. 07

  18. Thanks

  19. Light Source ◆ Violet Laser Diode (LD) relative output Wave Length : 408nm wavelength (nm) Typical Spectrum (by Nichia) LD head LD driver Violet LD Unit

  20. LD Intensity Distribution Npe the diameter of the bundle x (mm)

  21. Cable • CeramOptec (Kevin Bakhshpour): • Fiber: step index MM • P/N UV90/100/107P (P-polyimide) (~20 – 25 K$/cable) • P/N UV200/210/235P (~25 – 30 K$/cable) • 6 – 8 weeks • Romack (Peter Gordon): • Fiber: step index • 100 micron ($1.5/m) • 50 micron ($2.5.m); graded index ($0.5) • PVC Furcation tubing for single fiber cables • FC/PC connectors • jacketing?

  22. Cable • Fibertech-optica (Rafal Pawluczyk) • Fiber • AS100/110UVPI ($0.9/m -> $9900 for fibers) • AS200/220UVPI ($1.35/m -> $14,850 ) • 65.2/125 ($0.13/m -> $1430) • Fiberguide Industries (Tom Christie) • Fiber • SFS100/110 • SFS200/220 (50% more) • AGI6.25/125T (13% more than SFS100) • Fiber Labs (Jake Weise) • Fiber: • 190 micron ($7K) • 100 micron (11K) • 62.5 micron ($14K) Poor efficiency

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