Barrel PID upgrade K. Inami (Nagoya) Ljubljana, Hawaii, Cincinnati and PID group - R&D status - Structure design - Prototype study - Beam test - Photon detector - Electronics - Design study - To do, cost estimation

2 Barrel PID upgrade 2.6m 1.2m e - 8.0GeV e + 3.5GeV Focusing DIRC / fTOP / iTOP Aerogel RICH - PID (  ) detectors; Focusing DIRC, fTOP, iTOP - Cherenkov ring imaging detectors with quartz - Locate in the current TOF region

3 Barrel PID options Converging the detector design Wide bar (40~50cm W x 2cm T ), focus mirror (R=5~7m) Shape of readout plane depends on the choice of photon detector By A.Schwartz-san (Nagoya) (Cincinnati ) (Hawaii)

4 Structure Quartz: 255cm L x 40cm W x 2cm T Focus mirror at 47.8deg. to reduce chromatic dispersion Multi-anode MCP-PMT Linear array (5mm pitch), Good time resolution (<~40ps)  Measure Cherenkov ring image with precise timing information. MCP-PMT (TOP counter, Nagoya) 18 counters in 

5 Structure design Can locate iTOP standoff inside sBelle structure (iTOP, M.Rosen-san, Hawaii) CURRENT FUTURE TOP iTOP 16 modules in 

6 Structure design Just started structure design With KEK workshop engineer Need optimization Use honeycomb plates etc. (M.Rosen-san) Deflection ~250um Barrel Deflection with full Quartz Load ~1,150kg Barrel Deflection with full Quartz ~1,230kg Deflection ~300um

7 Prototype development Demonstration of the performance Quartz radiator (Fused silica) ・ Flatness:<1.2  m/m ・ Roughness:0.5nm Photon detector ・ Time resolution ・ Efficiency Filter ( >400nm) ・ Suppression of chromatic dispersion PMT quartz Prototype overview 915mm 400mm 20mm quartz 915mm 400mm 20mm 400mm Glued 20mm (Nagoya)

8 Quartz radiator Check the quality for time resolution Single photon pulse laser =407nm MCP-PMT Several incident position  No degradation of time resolution Enough quartz quality Propagation length [mm] Time resolution [ps] Line 1 Line 2 Line 3  <40ps Quartz MCP-PMT 47.2 deg. MCP-PMT

9 At Fuji beam line in June and Dec. Using real size quartz and MCP-PMT MCP-PMT: Multi-alkali p.c., C.E.=60% Check Ring image Number of photons Time resolution Beam test MWPC 1 MWPC 2 Lead glass + Finemesh PMT Timing counter 10mm  quartz + MCP-PMT  t0 < 15ps MCP-PMT (56ch) TOP counter Quartz bar (1850×400×20mm) Trigger counter Quartz + support jig

10 Beam test results Ring Image Similar with Simulation Number of photons Ave. number of photons; 15.7 as expected Time resolution 1 st 2 nd 3 rd 1 st 2 nd 3 rd [1count/25ps] Data Simulation Resolution(1 st peak) Data76.0±2.0 [ps] Simulation77.7±2.3 [ps]

11 Propagation length [mm] Time resolution [ps] Simulation Check time resolution For several incidence condition and channel Data agrees well with simulation expectation.  Confirmed the level of chromatic dispersion effect Time resol. vs. propagation length

12 Photon detector R&D Square-shape multi-anode MCP-PMT Multi-alkali photo-cathode Gain=1.5x10 T.T.S.(single photon): Position resolution: <5mm Semi-mass-production (14 PMTs) σ=34.2±0.4ps QE ： Ave. QE ： TTS ＜ 40ps for all channels TDC [1count/25ps] Wavelength [nm] QE [%]

13 Lifetime issue Lifetime test Multi-alkali p.c. with Al protection With square-shape MCP-PMT  Short lifetime, position dependence Difference with round-shape PMT Enough lifetime (>10 super-B year) Need to confirm the lifetime of round-shape MCP-PMT Need to confirm the difference Internal structure QE before againg QE after againg

14 Lifetime with round shape MCP with 10  m pore Multi-alkali p.c. Aluminum protection on 1 st MCP Initial Q.E.; 20% at 400nm Initial Gain; 4x10 6 TTS keeps <40ps. Need to improve for initial Q.E. and initial aging Slope seems to be manageable. Can expect to improve during R&D in next year Output charge (mC/cm 2 ) Relative QE Relative Gain ~3 super-B years ?

15 MCP-PMT R&D status Multi-alkali p.c. SL10 Added ceramic shield To protect gas feedback  Improved lifetime Obtained normal Gain and TTS Still need to irradiate more photons and study detail Need to improve correction efficiency (~35%  ~60%) Put Al protection layer on 2 nd MCP  Deliver April and May GaAsP p.c. SL10 Change the process method To improve yield rate Will add ceramic shield Preliminary result from HPK Old New

16 Readout elec. R&D (Hawaii) 6.4 ps RMS (4.5ps single) Waveform sampling Comparable performance to best CFD + HPTDC MUCH lower power, no need for huge cable plant! Using full samples significantly reduces the impact of noise Integrated module

17 Readout elec. R&D 16k channels 2k BLAB3 128 SRM 128 DAQ fiber transceivers 32 FINESSE 8 COPPER All pieces have prototypes in existence or in fabrication -- present performance results in July Already ~10% system Fabbed (Hawaii)

18 Design study Simulation studies Handmade + Geant3 (K.Inami, Nagoya) Geant4 + ROOT (K.Nishimura-san, Hawaii) Mathematica, Handmade ? (Cincinnati) Analytical calculation (M.Staric-san, Ljubljana)  Reconstruction program for gsim study Standoff 2 readout 1 readout

19 Design study with ring image Calculation with Mathematica Prefer to use wide bar and standoff, in order to obtain clear difference of ring images (Cincinnati)

20 Comparison btw. iTOP and fTOP For initial comparison purposes all assumptions are same … except fTOP: No expansion length, 2 cm by 44 cm detector plane (SL10* PMT). iTOP: 3.6 cm expansion length to a 10 cm x 44 cm detector plane (SL10* PMT) Separability comparable, slightly better with imaging. iTOP geometry optimization just started! Results may improve with optimization of bar width/thickness, focusing length, chosen photon detector, etc. 20 iTOP fTOP (Hawaii)

21 Performance check GaAsP, CE=35%, >400nm 10ps jitter (Nagoya)

22 Performance check With 10ps jitter GaAsP, CE=35% >400nm Multi-alkali, CE=60% >350nm

23 Simulation study Similar results with Nagoya ’ s simulation For B   case, 2-readout type shows better results. (M.Staric-san)

24 Cost estimate & Production time Quartz bars 16~18 modules (2x40x91.5cm 3 x3 + mirror, standoff) Okamoto optics (by Nagoya) 1800x 万円 ~ 3.6M$, 2 years Zygo (by A.Schwartz-san, Cincinnati) $72k x 3 x 16 + alpha ~ 3.7M$ From Taiwan (by C.H.Wang-san and P.Chang-san) ?? Photon detector (increasing gradually) MCP-PMT by Hamamatsu; 600 pieces for TOP, 3 years Multi-alkali photo-cathode; ~2.7M$ GaAsP photo-cathode; ~4.2M$ MCP-PMT by Photonis; ??? (expect cheaper price) Electronics LABRADOR; <$10/ch Structure

25 Summary Barrel PID based on TOP/DIRC Cherenkov ring imaging with position and precise timing (<50ps) using Quartz + MCP-PMT Wide bar (40~50cm W x 2cm T ), focus mirror (R=5~7m) Shape of readout plane depends on the choice of photon detector Started structure design Prototype study Expected performance by beam test Readout electronics with BLAB3 ASIC will be tested soon. Photon detector Lifetime test with round shape and square shape MCP-PMTs Seems manageable lifetime. Need to establish production reliability and lifetime Design study With several simulation programs Need to obtain consistent result first

26 What to do Prototype study Check ring image with focus mirror, quality of quartz radiators Electronics prototype performance Design study Simulation programs showing consistent results Design choice and optimization Robustness against multi-track events, beam BG Effect to outer detector, again Material of standoff, structure Distance btw. radiator and ECL Photon detector choice Lifetime for MCP-PMT Test with square-shape MCP-PMT from Hamamatsu and Photonis Performance and production reliability Hamamatsu vs. Photonis  Determine the size Photo-cathode (GaAsP/Multi-alkali) By next summer

27 Backup

28 Performance Full simulation with GaAsP photo-cathode + Focusing mirror >400nm filter, CE=35%

29 Barrel PID detector Cherenkov ring in quartz bar Reconstruct ring image using ~20 photons reflected inside the quartz radiator as a Babar ’ s DIRC. Utilize 3D information Arrival position (x,y) Arrival timing (t) Difference of propagation time for  is ~100ps