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Pileup Background Rejection

Fast Timing Detectors for FP420. FPF420@UTA. WHO?. UTA ( Brandt ), Alberta (Pinfold), Louvain (K.P.), FNAL (Albrow) + SACLAY (Royon), Stoneybrook (M. Rij). WHY?. Pileup Background Rejection. Ex, Two protons from one interaction and two b-jets from another. How?. Compare z-vertex

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Pileup Background Rejection

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  1. Fast Timing Detectors for FP420 FPF420@UTA WHO? UTA (Brandt), Alberta (Pinfold), Louvain (K.P.), FNAL (Albrow) + SACLAY (Royon), Stoneybrook (M. Rij) WHY? Pileup Background Rejection Ex, Two protons from one interaction and two b-jets from another How? Compare z-vertex for SVX with TOF z=c(TR-TL)/2 How Fast? z (mm) =0.21 t (psec) (2.1 mm for t=10 psec) 10 psec -> x40 to x30 rejection

  2. The Detectors : 1) GASTOF (Louvain) http://www.fynu.ucl.ac.be/themes/he/ggamma/Cherenkov/

  3. 5 psec GASTOF • Advantages: • Presents little material to beam • Extremely fast • Disadvantages: • No segmentation • Long

  4. The Detectors : 2) QUARTIC proton • 8 fused silica rods in z (my fused silica!) Mike’s idea Jaak’s drawing

  5. Spread in timing as f() since n() 60 psec Fused Silica Bars • 9 cm bars • Some converted to mini-bars

  6. Sketch of Mini-bar Solution 6 20 p 6 dimensions in mm, not to scale (mini-bar at 50 deg to p) ~ 60 Fused Silica ~ 10 Air light guide (Jim’s) (Aluminium box, or mylar lined plastic) 4 4 Taper 6  4 (4 is a guess) (Crude “Winston Cone”) Match to photocathode “sweet spot” UTA simulations showed this solution superior to long bars

  7. beam 3.7 cm QUARTIC Preprototype side view 9.0 cm 4.7 cm 1.97 cm 2.57 cm 50º 2.54 cm 2.54 cm 2.54 cm top view MCP-PMT 6.4 cm 1.53 cm top view (photo)

  8. 20 psec QUARTIC (V2) • Advantages: • Segmentation (8 x 4) • Compact • Disadvantages: • More material • Not as fast

  9. Baseline Plan 2 QUARTICs Lots of silicon 1 GASTOF

  10. T958 • Fermilab Test beam experiment to study fast timing counters for FP420 (Brandt spokesman) • Used prototype/preprototype detector with expensive or Louvain-made amplifiers and NIM/CAMAC discriminator/TDC to test concept • Sporadic mostly parasitic running Aug 12- Sep 14 (primary user Sep 7-10, 14) Time resolution for the full detector system: 1. Intrinsec detector time resolution 2. Jitter in PMT's 3. Electronics (AMP/CFD/TDC)

  11. First TB Initial Results For QUARTIC bar at 2300V Get 110 psec after correcting for variable height in bar (compared to 90 psec for G at same voltage); Efficiency typically .5 to .6/bar, low of .2, high of .9, at least part of dependence due to CFD performance G1-G2 For events with a few bars on see anticipated √N dependence <70 psec/Gastof (2500V) >90% efficiency

  12. Upgrade for T958 Phase II March 7-20 • New detector prototypes • New electronics • Improved DAQ • Improved alignment • Automated analysis and database routines, to allow instant and easier analysis • Improved tracking

  13. T958 Electronics Phase I: Amplifier : Hamamatsu Ortec Phillips Burle 8x8 MCP-PMT 25 um pore Constant Fraction Discriminator Ortec 934 (9307) TDC (Phillips 7186) SMA SMA Lemo 10 um Burle or 6 um Hamamatsu HPTDC Phase II: New boards (Louvain/Alberta) Phase III:

  14. Extrapolating Suppose we did no better than first test beam: 67 psec/GASTOF +8bars *.6 eff at 110, this would give 40 psec track measurement or about ~x10 background rejection. Suppose (40,40,30) for QUARTIC (Elec,MCPMT, detector) (64 psec/bar), and .75 efficiency gives 26 psec for one QUARTIC alone, combined with a GASTOF (elec=40,tube=20,det=10) of 44 psec, gives 22 psec track (x18). Ultimately QUARTIC might be (20, 15, 20) but lets assume limit of (25,25,25) gives 11 psec for 2 QUARTICS + GASTOF (15,10,5) gives 18 psec -> total <10 psec

  15. Louvain Electronics: • First CFD prototype produced and WORKING!!! Designed a NIM multi-channel board with remote control thresholds(directly from LabView using RS232) • New VERY fast (14 GHz BW) amplifiers from Mini-Circuits show very good characteristics Note: One POSITIVE signal output

  16. . . . . Q1=Q 10um tube Q11-Q18=12mm bars Q21-Q28=15mm bars Q33-Q36=90mm bars Q2=R 25 um tube R11-R18=12mm bars R21-R28=15mm bars MCP-PMT layout beam

  17. Personnel Chart/ Time at Fermi FEBRUARY| MARCH M T W TH F S SU M T W TH F S SU M T W TH F S SU M T W TH F S SU M T 26 27 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Pedro Sean Tomek Andrew Luc Shane

  18. GASTOF Stand

  19. First Results from TB2 QUARTIC Extremely promising 90% efficiency, <70 nsec/bar! Unfortunately, the results were a mirage caused by Coherent noise Furthermore GASTOF2 inefficient and leaks

  20. Coherent Noise! If a row gets blasted, whole tube ground oscillates, 3 nsec later

  21. Coherent Noise! ~3 nsec time

  22. Table shifted 12 mm, to move extra bars out of beam

  23. How to proceed? Grounding other bars at connector did not help Need new tube to fix problem Took data with table offset Took data with scope in remote mode See following talks

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