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Scintillation counters for the CDF Muon Upgrade DPF 2000, Columbus Ohio

Scintillation counters for the CDF Muon Upgrade DPF 2000, Columbus Ohio G. Pauletta, for the CDF Collaboration. Outline : Overview upgrade objectives and the role of the scintillation counters The Run I counters Characteristics, performance and problems

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Scintillation counters for the CDF Muon Upgrade DPF 2000, Columbus Ohio

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  1. Scintillation counters for the CDF Muon Upgrade DPF 2000, Columbus Ohio G. Pauletta, for the CDF Collaboration • Outline: • Overview • upgrade objectives and the role of the scintillation counters • The Run I counters • Characteristics, performance and problems • Filling the holes and extending the coverage: New counters • design and performance • Refurbishing old counters • method and results

  2. Muon Upgrade objectives • Trigger on muons at increased luminosity ( >1032) and shorter bunch crossings (396 ns, 132 ns) • Increase coverage RUN I -------- > RUN II CMU CMP/CSP CMX/CSX BMU/BSU Coverage 0<h<0.6 0<h<0.6 0.6<h<1 1<h<1.5 drift time 800 ns 1.4 ms 1.4 ms 800 ns

  3. The muon trigger scintillation ctrs. serve to “time stamp” and/or reduce uncorrelated b.g. at level 1

  4. Muon Upgrade subdetectors Intermediate Muon BMU + BSU + TSU (new) Central Muon eXtension (CSX + CMX) CentralMuon uPgrade (CSP + CMP) (new) (old) Central Muon chambers “miniskirt” (new) lower 90o

  5. Old counter design PVT - base scintillator (NE114) CSPs 30 cm 3 m long EMI 9815 PMT 2 cm thick CSX “minskirt counter” ~ 2m CSX “arch” counters ~ 2 m

  6. New counter design Scintillator: UPS-923A from Monokristal, Kharkov, Ukraine. Polystyrene doped with PTP(2%) and POPOP(.03%) Wls fiber: double - clad Y11 fiber from Kuraray fiber “mirrored at far end. Hamamatsu H5783 photomultiplier + Cockroft - walton base Ctr. type number dimensions CSP 150 320cm x 30.5cm x 2 cm BSU 432 164 cm x 17 cm x 1.5 cm

  7. Counter readout Wls fiber PAD

  8. New counter assembly LED LED PAD

  9. Counter output calibration Each counter output is calibrated in absolute terms (number of photoelectrons/ADC channel) by exposing it to low - level pulsed light ( ~1 p.e./pulse) and locating the centroid single p.e. distribution.

  10. Counter response ( in photoelectrons) to cosmic muons is measured in steps of ~20 cm and the results are fitted to extract counter characteristics Measurements are automated (4 ctrs at a time) npe Offline fit distance (x) from pmt From the fit , one extracts: n0 (zero extrapolation) r (reflection coefficient of fiber mirrors) keeping known fiber attenuation constant at 3 m npe(x) = n0(exp(-x/l) + r * exp(-(2L -x)/l))

  11. Counter parameters and test results using cosmic muons

  12. Problems with “Old” counters: efficiencies were lower than expected CSP efficiencies CSX efficiencies time dependence evident

  13. Attenuation - length for good an bad counters Or LED Response to cosmic muons confirms degradation in attenuation-length and reveals a corresponding degradation in light yield

  14. We unwrap some counters Most of the counters display pronounced aging effects Good NE114 Bad NE114

  15. Old Counter refurbishment: wls fiber ribbon addes to one side and routed to existing pmt

  16. CSP Repair: Work at Lab 5

  17. Distributions of fixed counter outputs Average npe = 16 p.e. Average npe = 58 p.e.

  18. Muon Upgrade objectives • Trigger on muons at increased luminosity ( >1032) and shorter bunch crossings (396 ns, 132 ns) • Increase coverage RUN I -------- > RUN II CMU CMP/CSP CMX/CSX BMU/BSU Coverage 0<h<0.6 0<h<0.6 0.6<h<1 1<h<1.5 drift time 800 ns 1.4 ms 1.4 ms 800 ns

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