1. TOF Emittance Measurement1m.rayner1@physics.ox.ac.uk Pion Emittance Measurement with the TOFs? Mark Rayner 11 December 2008

2. TOF Emittance Measurement2m.rayner1@physics.ox.ac.uk Complications with a Pion Beam Pion  muon decays –c/  of the pion is 7.8m At 250 MeV/c, =(250/140)*7.8m=13.9m and 35% of the pions decay between TOF0 and TOF1 At 400 MeV/c, =(400/140)*7.8m=22.3m and 30% of the pions decay between TOF0 and TOF1 –Can we identify them based in time of flight? Pion decay –P  * = (M  2 – M  2 )/(2M  ) = 29.9 MeV/c Dipole acceptance –Rectangular distribution width +/-10% So distributions will overlap and time of flight cannot help Can the Cherenkov help? –It can separate muons/pions which decay Before TOF0 Between TOF0 and Ckov? Incident pions Muon rest frameBackward decaying muons Forward decaying muons pE  Tof 8mPEPE  PE  MeV/cMeV nsMeV/cMeVMeV/cMeV nsMeV/cMeV ns 260295.300.882.1130.2929.90110.14141.47176.780.8033.32267.61287.830.9328.68 235273.540.861.9531.0429.90110.14126.45165.000.7734.80243.29265.380.9229.09 210252.390.831.8032.0529.90110.14111.30153.700.7236.83219.11243.400.9029.62 Incident pions Muon rest frameBackward decaying muons Forward decaying muons pE  Tof 8mPEPE  PE  MeV/cMeV nsMeV/cMeVMeV/cMeV nsMeV/cMeV ns 360.00386.260.932.7628.6129.90110.14200.71226.980.8830.16365.70380.760.9627.76 400.00423.790.943.0328.2529.90110.14224.17247.960.9029.50405.19418.820.9727.56 440.00461.740.953.3027.9829.90110.14247.53269.270.9229.01444.76457.210.9727.41

3. TOF Emittance Measurement3m.rayner1@physics.ox.ac.uk TOF Calibration Requirements for an Emittance Measurement Emittance Measurement Assume Linear Beam Optics Use forthcoming TofEmittance app TofSpacePoints Sufficiently well calibrated TDC between detector planes in TOF 0 and TOF 1 Needed to distinguish multiple hits Use new TofCalibration app Momentum measurement Required for tracking (create ‘TofTracks’) Sufficiently well calibrated TDC between TOF 0 and TOF 1 Assume constant path length Use new TofCalibration app TOF0 to TOF1 calibration Electrons (800cm/30cm)ns between stations Station calibration Electrons (2.5cm/30cm)ns between planes Plane calibration Any beam Use reference slab in other plane Time walk calibration Any beam Pulse by pulse ADC correction to TDC ? ?

4. TOF Emittance Measurement4m.rayner1@physics.ox.ac.uk TOF Plane Cable Length TDC Calibration

5. TOF Emittance Measurement5m.rayner1@physics.ox.ac.uk Conclusion Q789  /2 optics calculated for 250 MeV/c particles before TOF 0 Will recalculate for 400 MeV/c However an unknown ~35% of the ‘pions’ will have decayed between TOFs Nevertheless important TOF calibration work can be accomplished –<100 MeV/c electrons TOF0  TOF1 calibration Station calibration –Any beam Plane calibration –Investigation into timewalk fADC-TDC correlation not yet understood New apps (TofMonitor and TofCalibration) can help with this g 07 [T/m] T/m g 09 –g 08 TOF0 to TOF1 calibration Electrons (800cm/30cm)ns between stations Station calibration Electrons (2.5cm/30cm)ns between planes Plane calibration Any beam Use reference slab in other plane Time walk calibration Any beam Pulse by pulse ADC correction to TDC