1. New particle ID detector for Crystal Ball at MAMI-C Daniel Watts, University of Edinburgh John Annand 1, B. Briscoe 3, A. Clarkson 2, Evie Downie 1, D. Glazier 2, S. Lumsden 2, Daria Sokhan 2, C McGeorge 1,Claire Tarbert 2 1- University of Glasgow 2- University of Edinburgh 3- George Washington university

2. Constraints of MWPC-I and targets → siting of PMTs at downstream end Design specifications Good separation of p, with little overhead in material before MWPC and CB detectors PID-I

3. MWPC-II & PID-II MWPC-II redesigned for MAMI-C experiments PID-II outside MWPC  inbetween the MWPC chambers  → Opted for setup similar to PID-I But PMTs at upstream end - TAPS

4. r PID-II >r PID-I Keep same segmentation (24) t scint = 4mm (PID-I: 2mm) PID-II schematic CB Tunnel PID-II scintillators MWPC supports MWPC Chambers PMTs  MWPC = 133mm 500mm PMT support ring  beam PID-II – removable! (redesigned MWPC connectors) PID-II schematic  PID(INNER) = 108.4mm Hamamatsu H3164 - 10

5. 12345678 Delivery of scint. Cutting & prep of scint. Lightguide manufacture Element assembly & tests Detector assembly & tests Total construction time ~ 5.2 months Implementation into MWPC & CB months PID-II – schedule and status Delivery of PMTs ~1.5 month delay - Replacement of scintillator strips. New batch of manufactured by ELJEN 7

6. PMTs Scintillator HV input and signal readout 3He target nose Al support ring

7. PID-II GEANT Simulation Use PID-I simulation parameters – light output, light collection efficiency, QE … → Reasonable agreement with experimental data Include increase in PID-II scintillator thickness Flat KE distribution up to 0.7 GeV Isotropic angular distribution No shower shape restrictions Pions K+K+ Protons Energy deposited in CB (GeV) Energy deposited in PID-II (GeV)

8. 3 day old bananas - all PID2 elements 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 18 17 19 20 21 22 23 24 Data from 3He target - NO  restriction or correction for path length in the scintillator CB Energy (MeV) PID2 Ebergy (a.u) Proton punch through

9. Detector ready for use Summary

10. Data from first test PID Trigger – CH2 target All 24 elements give good signals PID2 Protons Pions PID1

14. Liquid hydrogen target Radius mwpc = 66.5cm

15. Active detector region PID-II test module – light attenuation 90 Sr beta source Observe position of landau as source moved along scintillator → light attenuation PID-II Test module PID-I Test module Enhancement near PMT Distance from PMT (mm) Position of landau peak (arb units)

16. CB Tunnel PID-II Scintillators  inner = 116.4mm MWPC supports MWPC Chambers PMTs  MWPC = 133mm (outer diameter of PID support ring) 500mm scintillator length PMT support ring  beam  PID(INNER) = 108.4mm (inner diameter of PID ring) Hamamatsu H3164 - 10 Plastic downstream scintillator support  inner = 113.25mm (For detail see additional figure) Chamber length (between the supports) = 570 mm Schematic of PID-II for use with the Crystal Ball@MAMI-C D. Watts 20/04/06 BEAM

17. PID-II PID-I support ring r outer -r inner = 14mm 4 mm clearance each side to the polarised target. Hydrogen target will have problem – clearance = 0mm! 65.5 51,5

18. PID-II & polarised target

19. PID-II PMTs Same tubes and bases as for PID-I BUT use new packaged tube + base assemblies -include magnetic shield Hamamatsu H3164 - 10

20. Preliminary decay gammas from nucleon knockout 12 C( ,ppp) 9 Li Q value Low energy clusters from shaded region 2.69 MeV E  =400-500 MeV i=1 3 Also look at pp, 4p, 5p … knockout Missing Energy (MeV) = E  –  T pi –T rec Energy of cluster (MeV)

21. Simulated  + signals in Crystal Ball No restriction on shower size ≤ 2 crystals in  + shower  + decay Nuclear interaction Incident  + energy (GeV) Highest cluster energy (GeV)

22. Very preliminary decay gammas from nucleon knockout 12 C( ,ppp) Q value Low energy clusters from shaded region 2.69 MeV

24. r PID-II >r PID-I Same segmentation (24) L scint chosen to give PID Info for all proposed targets L scint =50 cm (PID-I 32cm) PID-II – schedule and status PID-II Test module PID-I Test module

25. New polarised target design