1 QUARTIC, A TOF for ATLAS/CMS Forward Protons You didn’t know that ATLAS+CMS had forward protons? FP420 = Forward Protons 420m downstream of CMS & ATLAS (joint R&D project) Physics is p H/WW/ZZ p Measure p’s with very high precision within 3 mm of beam Gives mass and quantum numbers of central state. Andrew Brandt (UTA) Jim Pinfold (Alberta), Mike Albrow (FNAL)

2  Tracker, perhaps 10 layers per station, 3 stations, 3D silicon (edgeless, 10um res., fast, rad hard).... Hawaii/SLAC + Brunel  TOF counter, quartz fiber Cerenkov + MCP-PMTs  Vacuum mechanics: Detectors in secondary vacuum, space constraints between beam pipes, not room for roman pots. High precision movement (microns), reproducibility, fail-safe.  Funding, approvals, etc. FP420 Challenges

3 n=1n>>1 Cerenkov Effect Use this property of prompt radiation to develop a fast timing counter particle

4 It’s been done! Can’t put our PMT in 7 TeV beam!

5 Preliminary UTA drawing of Mike Albrow’s concept for a fast time resolution Cerenkov counter: proton Microchannel plate PMT Initial design used 2 mm 2 rods, but not enough light, this drawing shows 6mm 2 rods QUARTIC z=c(TR-TL)/2  z (mm) =0.21  t (psec) (2.1 mm for  t=10 psec)

6 Where do Protons go at 420m  3mm x<2.5 cm 120 GeV Higgs courtesy Peter Bussey, Manchester (irony of particle physics—easier to get plot of protons from Higgs than single diffraction) x x y x

7 GEANT4 Simulation (Alberta) A GEANT4 simulation is well underway (see GEANT4 produced graphics above. The detector simulation includes: Tracking of Cerenkov photons to the MCP-PMT through the medium. Wavelength dependent refractive index of the medium Wavelength dependent attenuation of the photons Wavelength dependent reflectivity of the aluminium reflector Timing of photons from generation to the MCP-PMT The effects of coupling grease (if necessary)

8 QUARTIC Background Rejection (UTA) 1)2 single diffractive protons overlayed with a hard scatter (1% of interactions have a proton at 420m) 97.4% of events primary vertex and fake vertex from combining proton times more than 2.1mm (1  ) apart ; 94.8% if 20 psec 2) double pomeron overlayed with a hard scatter 97.8% of time vertices more than 2.1mm apart; 95.6% if 20 psec 3) hard SD overlayed with a soft SD 95.5% of time primary vertex and fake vertex more than 2.1mm apart; 91.0% if 20 psec

9 Cerenkov Light in Fused Silica (UTA): UV is important! total pe’s : 130 pe/6mm rod λ#PEQE#p*Q EΘcn % % % % % total638.0 #P aveθc aveLQ E ave#P.ave*QEave cm15.57%648.0 maybe we should call it Fusstic

Single n=1.52  c=49  ; 7.4% of pe’s in 10 psec 21.3% in 50 psec  over including QE 1.9% of pe’s in 10 psec 19.1% in 50 psec Preliminary Time Distributions: 50 psec red = totally internally reflected light green = extra light if aluminized

11 Next Steps Preliminary design studies are promising Need to learn more about MCP’s; preliminary indications are Burle tubes are currently only option due to size of active area Burle has 1.5 mm pixels could give very useful x-segmentation for measuring multiple protons in same detector, but it seems that best timing using single MCP_OUT channel (1/tube) (Wilma Raso) Starting to think about electronics (Alberta) Test beam at Fermilab summer 2006