1. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 1 Fast Timing Counters for FP420/CMS and Test Beam Particle ID Mike Albrow, September 14 th 2006 FP420 (Forward Protons at 420m from CMS/ATLAS) R&D project pp H Measure p’s very well  M(H), J=0?, CP = ++, Hgg coupling... Difficulty: SM-H(120-160) ~ 1-10 fb. Need high luminosity (~ 30/fb) with multiple interactions. Pile-up: p’s from different events. Precision timing on p’s can reduce this: iff from same interaction.  Factor 20 – 30 reduction in pile-up B/G, + kinematic constraints.

2. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 2 For FP420 we have tested two prototype designs. Both use Cerenkov light – prompt – GASTOF and QUARTIC. p MCP- PMT 45-MIRROR THIN WINDOW 1 atm. C4F8O 1 m. GAS-Time-Of-Flight Aperture ~ 10 x 25 mm This is what I am suggesting to use for TOF ID in MTEST. QUARTIC (QUARtz TIming Cerenkov) Quartz bars 6mm x (6 – 1.5)mm x 20mm with air light guides to MCPMT pixels. 8 measurements on a track. Can measure 2 separate tracks >3mm in y. Used area 10mm x 25mm ~ 60mm quartz so thick for MTEST. All light arrives within 3 ps

3. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 3 GASTOF for prototype tests t958 Univ. Louvain For MTest: 1m. long Thin mirror/windows

4. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 4 In Mtest (until this evening!): GASTOF 1 GASTOF 2QUARTIC 1 QUARTIC 2

5. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 5 It’s (10ps) been done! The challenges are the electronics and geometry for FP420. SLAC group (Va’vra) got 30ps for single p.e.

6. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 6 Photodetector We concentrate on Burle 2” x 2” MCP PMT (Micro-channel plate PMT) Hamamatsu have higher performance with 10 um channels, but area smaller. Burle has 25 um channels (makes it slower) but are developing 10 um. Burle have given us tubes to test. 25um pores and one 10 um pore tube. Univ. Louvain bought 2 tubes for GASTOFs  M Test. These have an 8 x 8 array of 6mm pixels (  48mm x 48mm (2”)) For GASTOFs one output... couple pixels “isochronously”

7. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 7 Cerenkov light in C4F8O (Octafluorotetrahydrofuran, 2.5)... at atmospheric pressure. At 2 atm. K/p threshold is 6.5/12.5 GeV/c. Asymptotic #pe = 54 non-flammable and non-toxic

8. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 8 e

9. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 9  We must have a good reference signal free of jitter between stations. This is as important as the detectors themselves.  Temperature control? Return path control?  Need to discuss with RF/clock experts. Sophie Baron is contact at CERN for LHC timing issues. Assuming jitter problem solved, calibrate with (p-independent). I have not compared abilities with conventional (P.H. or RICH or DIRC etc) Cerenkovs. This is a new approach which (a) meshes well with CMS application (b) Could be developed (Henry!) to 1 ps

10. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 10 CMS or ATLAS LHC-RF (400 MHz)  sharp regular pulse “TDC” QUARTIC/ GASTOF QUARTIC/ GASTOF START STOP Optical Fiber Comparator (control) May not be necessary, but can test for L-R propagation time differential changes EW BPM (optimized for timing) BPM (optimized for timing) Tell where p is w.r.t. bunch centroid. (few mm/70mm) Fine correction on p_incident. Compare with sum time from pp A possible reference time scheme (LHC): (250 ps) Single mode? CENTIME ? FO

11. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 11 Three Gastof’s : redundancy, cross-checks, improved resolution (3-point fit to “timetrack”) Electronics, Set-up for MTest MCP PMT HV v.stable no ripple ATTENUATOR?ATTENUATOR? AMPLIFIER?AMPLIFIER? CONSTANT FRACTION (?) DISCRIMINATOR ADC TDC <=25ps/bin OPTICAL REFERENCE TIME OPTICAL to ELECTRICAL LOCALCENTRAL Only optical fibers TDC bin/4 differences Temperature controlled Stabilized Power Supplies Faraday cage? Short straight SMX cables, minimize connectors light

12. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 12 LR t z This is ambitious, not for LHC Day 1, but P/U worse in 2010! This can identify (in principle) interactions that have particles in both L and R detectors. All are background for p+H+p! z from central tracks

13. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 13 Fast Timing Layer Detectors ~ Existence proof: Burle 48mm x 48mm MCP PMT (Micro-channel plate PMT) as for QUARTIC Developing 10 micron channels, approaching 10 ps. Tile the plane with these QUARTZ PLATE MCP-PMT PARTICLES Approximate numbers: ~ 250 each side, perhaps 1000 1cm x 1cm pads Expensive solution (~1M$?) but cost could drop. Questions: Simulation, acceptance, background crap and especially RADIATION HARDNESS. Another solution?

14. Mike AlbrowSept 14 th 2006Time-of-Flight with GASTOFs im Test Beam 14 SUMMARY  High precision timing (<~ 10-20 ps) has important future roles:  It is essential for pile-up rejection in pp  p+H+p. p+WW+p at LHC  A very similar set-up can do particle I.D in beams (MTest Upgrade)  <2 ps, large areas open up new possibilities (I.D., Gaps in spacetime)  MCP-PMT is probably best fast photo-detector for now. Later??