1 / 21

RPC and LST at High Luminosity

RPC and LST at High Luminosity. Review the Babar muon detector configuration after 2005 Extrapolations based on background studies Large uncertainties Possible future improvements. Hawaii Super B Factory Workshop January 19-22, 2004 Giancarlo Piredda, INFN-Rome. RPC belt.

darleenw
Download Presentation

RPC and LST at High Luminosity

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RPC and LST at High Luminosity • Review the Babar muon detector configuration after 2005 • Extrapolations based on background studies • Large uncertainties • Possible future improvements Hawaii Super B Factory Workshop January 19-22, 2004 Giancarlo Piredda, INFN-Rome Giancarlo Piredda

  2. RPC belt Gap #19 (new) 10cm steel 5x2.54cm brass plates (Gaps 8,10,12,14,16) double gap RPC Easy access Forward Endcap Upgrade 2002 Giancarlo Piredda

  3. RPC UpperLimits on the Hit Rate • Set by electronics Strip signal held in FEC for 12.5 ms (deadtime) max rate 80 kHz/strip corresponding to about 30 Hz/cm2 • Set by the streamer mechanism Depending from the local RPC material and operating point believed to be somewhat lower but not much different than the electronics limit • RPC damage Degradation is also likely to start at similar values Giancarlo Piredda

  4. Aging – Graphite Layer Above 0.6 C/cm2 surface resistance rises rapidly Giancarlo Piredda

  5. Aging – Bakelite Resistance J. Va’vra 4*10^11 Wcm Above 0.5 C/cm2 bakelite resistance starts increasing Could be alleviated by flowing humid gas Giancarlo Piredda

  6. Counting rates in the forward endcaps Rate=A*I_HER+B*I_LER+C*LUMI R.Messner Outer Layer rates follow LER beam losses Inner Layer rates due to Luminosity and HER Special run Usually layer 15 is off Giancarlo Piredda

  7. Background is not uniform in the cross-section Layer 11 Layer 1 Layer 15 Layer 14 Giancarlo Piredda

  8. R.Messner 1C/cm2 1 year Lumi 6 12 18 20 35 10**33 Giancarlo Piredda

  9. Giancarlo Piredda

  10. Relevant remarks With the present rates and the present set-up the outermost layers are not safe. • Layer 14 rate is about 100 kHz/RPC which corresponds to 100 mA and to an integrated charge of 0.1 C/cm2 per year • The bulk contribution comes from the LER • Shielding is necessary to allow full exploitation of outermost layers • Layer 1 (middle) rate is about 40 kHz/RPC , could reach dangerous doses near the beam line • needs further investigation and possibly dedicated shielding Giancarlo Piredda

  11. Shielding • The LER beamline on the forward is almost unshielded • Planning for 20 cm steel wall (engineering project ready and approved) • Based on the effect of almost the same amount of steel in between layer 15 and 12, the background rate reduction is estimated to be a factor between 5 and 30 (say 20 in average) • A test wall (16” by 32”) installed in Oct 2003 and proven to be effective • Installation foreseen in Summer 2004 shut-down Giancarlo Piredda

  12. Shielding Wall Giancarlo Piredda

  13. Layer 15 projection with and without the shield wallIntegrated Charge/cm**2Linear Scale R.Messner Wall starts July 2004 Giancarlo Piredda

  14. The after 2005 muon detector • Barrel equipped with LST • Forward and (Backward) EndCap (and “Belts”) equipped with RPC • Shielding wall will be there • The annual charge will be of the order of .05 C/cm2 at 0.3*10^35 lumi in the worst case (layer 1 without additional shielding). • In any case the two outermost layers could be easily replaced (with RPC or LST). Giancarlo Piredda

  15. Conclusions • Extrapolations made on Pep-II ‘adiabatic’ upgrade (up to 0.35*10^35cm^-2s^-1) • Need full simulation for having more reliable predictions • RPC forward endcap could stand high luminosity with appropriate shielding. • Further improvement on the accumulated charge still possible (alternate gas mixture) Giancarlo Piredda

  16. ...and LST • Dec 2002 - LST choice for IFR Barrel • Nov 2003 - Module design finalized • Jan 2004 - Production starts • Aug 2004 - Installation of 2/6 sextants • Aug 2005 - Installation of remaining 4 sextants • Very Large Effort Giancarlo Piredda

  17. LST Tube Design The tube design has evolved into: Single-layer with a large cell (15 x 17mm) 8 wires/tube, 2 wires ganged together Readout wires for “f” coordinate eliminate cathode strips for f readout ground plane with embedded signal transmission line fabricated at Slac Transverse (“z”) coordinate readout via cathode strips z-strips planes fabricated at SLAC Tubes dimensions: ~ 20 x 154 x 3580 mm Tubes are manufactured and assembled in Italy (PolHiTech) QA/QC and Module Assembly in Princeton and OSU DAQ electronics includes FIFO buffer allowing multiple hit in the 12 ms trigger latency. Giancarlo Piredda

  18. LST rates • Maximal rate 100 Hz/cm • Extrapolation as follows - 30 Hz/cm at 2*10^35 cm^-2s^-1 (3% occupancy) - 150 Hz/cm @ 10^36 (30% ) - Not uniform in depth Aging souldn’t be a problem... Giancarlo Piredda

  19. In the Barrel annual dose less than 10 mC/cm Well below the ‘dangerous’ 100 mC/cm border Giancarlo Piredda

  20. Giancarlo Piredda

  21. Conclusion • No problem expected for the Barrel LST at luminosity up to a few 10^35cm^-2s^-1. • New detector supposed to have a long and safe life • Plan to study avalanche mode for high rate (forward endcap) environment. Giancarlo Piredda

More Related