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Sensitivity of HO to Muons

Sensitivity of HO to Muons. Shashi Dugad for HO group India-CMS Meeting 6-7 Oct.-2003. Sensitivity of HO to Muons. Shashi Dugad India-CMS Meeting 6-7 Oct.-2003. HO Setup. 1 Sector (6 Trays) of Ring-1, Ring-2 and 5-Trays of Ring-0 hooked up in the testbeam

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Sensitivity of HO to Muons

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  1. Sensitivity of HO to Muons Shashi Dugad for HO group India-CMS Meeting 6-7 Oct.-2003

  2. Sensitivity of HO to Muons Shashi Dugad India-CMS Meeting 6-7 Oct.-2003

  3. HO Setup • 1 Sector (6 Trays) of Ring-1, Ring-2 and 5-Trays of Ring-0 hooked up in the testbeam • 2 Readout Box (RBX) of HB configuration containing 4 HPD each were provided for optical readout of HO towers • 20,30,30 towers each in Ring-0,1,2 respectively • Eta-tower=5 (Ring-1) cannot be connected due to constraints from RBX

  4. HO Readout • Only 4-HPD (18 towers each) could be connected to DAQ system at any time • Depending on the beam direction, following configuration chosen;

  5. HO Read Out • Signal Flow: • Tile  Pigtail  Optical Cable  HPD  QIE  Transducer  Optical fiber communication cable  HTR • Charge data from each tile is readout at every 25 nSec and stored on trigger • Data from 20 time slices (500 nSec) is stored for each event

  6. Muon Runs • Muons of 225 GeV shooted in each tower • 10 K events taken for each tower • Data is stored in root-tuple • Data read through HTBDAQ library • All HB towers upto Phi_tower = 6 scanned • All HO towers from Phi=2-6 scanned except one tower in each phi-strip

  7. Analysis • Average charge/slice distribution obtained • Latency: Distribution of Slice# giving max. charge obtained • Signal contained in 5-time slice for HO and 7-time slices for HB detector • Higher signal width as compared to last year data • Signal charge obtained by summing 10-14 time slices in HO • Signal charge obtained by summing 0-4 time slices in HO • S/B Ratio = Signal Peak/Ped. RMS

  8. S/B Ratio Study • Charge readout by 4 different capacitor banks • Each of them may have different ped. peak and RMS • Obtain noise distribution as per Cap-ID • S/B does not change with Cap-ID correction • Signal charge is dominantly coming from 3-time slices • Obtain S/B for 3- time slices • Obtain S/B by choosing slice with max. charge and then summing in 3-slices • Signal increases with HV • Obtain S/B at diff. HV

  9. Summary of S/B Ratio Study • Signal Strength and S/B Ratio for HO Detector • 3d Dynamic selection of 3-slices

  10. HO for Muon Trigger • Important to see effect of noise on trigger efficiency • Signal Eff.(Q) = Fractional area beyond Q for signal run • Purity(Q) = 1. – Fractional area beyond Q for pedestal run • Signal Eff. And Purity obtained at different values of Q for each tile • Ring-1 has low purity at moderate efficiency, need to enhance signal strength • Sort HPD’s by QE • Enhance HV to HPD

  11. Summary • Clean muon signal seen in all HO towers • No dead channels • S/B Ratio: • 4.5 for Ring-0, 2.2 Ring-1 and 3 for Ring-2 • No significant improvement with 3-time slice signal size or CapID criteria • Latency: Signal Peak Charge has a spread in 3-slices • Ring0, Ring2 has reasonable purity at high efficiency, Ring-1 needs improvement • 30% improvement in S/B @10 KV • Pre-selection of HPD expected to improve S/B by another 20-30%

  12. LASER CALIBRATION SETUP • Only 1 of the RBX (HO-1, located behind Ring-2) was lighted with laser light pulses • Data from Spigot=11,12,13 used for analysis • Spigot-14 had problem with 3-channels in the readout

  13. High Intensity LASER Runs • Light Intensity correction using PIN is important and depends upon the accuracy with which PIN signal is measured? • Should be much better than statistical accuracy of HPD pixel signal (~1% at high intensity) • Light intensity correction can be obtained by summing of normalized HPD pixel signal • Statistical accuracy of this would be 1/Sqrt(N) better than the pixel (N=3*18 for this dataset) • This will work provided systematic effects are much smaller than statistical accuracy • Usage of high intensity runs depends on deeper understanding of these issues • LOW intensity runs (9535, 9537) are used in the current analysis

  14. Analysis • Get ped. and signal distribution for each HPD pixel and PIN diode at different LASER intensity. • 7-time used for obtaining signal charge (7-13 for HPD and 3-9 for PIN) • Get intensity correction using normalized PIN and HPD signal distribution • Apply intensity correction and re-obtain signal distribution • Get peak and sigma using gaussian fit • Tails seen signal distribution • Using these parameters, obtain # of p.e. and calibration factor (#of p.e./fC) for each pixel at each intensity

  15. Results • Low intensity runs gives calibration factors of 3.6  0.2 p.e./fC • Variation of calib factors among different pixels are not very high • Intensity corrections can be obtained form HPD itself • Bright intensity runs could not be used for obtaining calibration factors

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