2004/12/04 RICH2004 Workshop 1

Development of RICH Counters for Belle Upgrade

Toru IijimaNagoya University

KEKB/Belle Plan Belle PID Upgrade Plan Status of TOP Counter Summary

RICH2004 Workshop 22004/12/04

Carb cavity (2006) Lpeak = (3-5) x 1034cm-1s-1

Lint = 1ab-1 by 2007?

Super-KEKB +RF, ante-chamber etc. Lpeak = (3-5) x 1035cm-1s-1

Present Lpeak = 1.4x1034cm-2s-1

Lint = 300+ fb-1

KEKB/Belle Plan

Letter-Of-Intent available (KEK-Report 2004-4), Not decided yet

RICH2004 Workshop 32004/12/04

Far precise CKM CPV in bs penguin modes

ex. BKs, ’Ks, Xs AFB in BKll, Xsll

Charged Higgs (ex. BD) LFV in decay (ex. )

Physics Objectssin21() (’04) = 0.73±0.04 for <charmonium> 0.41±0.07 for <bs penguin>

3.8 deviation

Discovery of CPV in B decays

Precise test of SMand search for NP

Study of NP effect in B and decays

Identification of SUSY breaking mechanism

time or

integrated luminosity

Yes!!

NP discoveredat LHC (2010?)

Now300 fb-1

if NP=SUSY

Present KEKB/Belle

Super-KEKB/Belle

RICH2004 Workshop 42004/12/04

/ KL detection 14/15 lyr. RPC+Fe

Tracking + dE/dx small cell + He/C2H5

CsI(Tl) 16X0

Aerogel Cherenkov counter + TOF counter

Si vtx. det. 3 lyr. DSSD

SC solenoid1.5T

8GeV e

3.5GeV e

2 pixel lyrs. + 3 lyr. DSSD tile scintillator

pure CsI (endcap)

remove inner lyrs.

“TOP” + RICH

New readout and computing systems

Belle Upgrade

RICH2004 Workshop 52004/12/04

Particle ID in Belle

fake(K)<10%

eff.(KK) >90%

Calibratiopn byD*+D0+, D0K-+

RICH2004 Workshop 62004/12/04

Motivation of PID Upgrade Improve separation for K/, and also for hopefully.

Extend momentum coverage in the forward endcap. Endcap-ACC (n=1.03) functions

only for flavor tagging

Reduced material thickness, and

more homogeneous distribution. 30% in total = 18% (ACC) + 12% (TOF) PMTs dominate for ACC

To cope with increasing background. TOF may not survive ACC seems to be OK

@ x10 backgroundW/ MQT.

Physics TargetsB /KD/DKB /K*(bd/s)B K ll, K Full reconstruction

Less systematics for precise

measurements

RICH2004 Workshop 72004/12/04

Idea of PID Upgrade Baseline

Barrel TOP Counter Endcap Aerogel RICH

Other ideas Focusing DIRC TOF w/ finer segmentation

co-exist with the present Barrel-ACC to cover high momentum

PrototypePrototype

RICH2004 Workshop 82004/12/04

Proximity Focusing Aerogel-RICH Candidate for the forward endcap. Proof-of-principle w/ flat panel PMT. New idea of dual-(multi-) radiator

for improvement. = 14.6mr, Npe = 9.1

w/ focusing (n1/n2=1.047/1.057)K/ sep. = 4.8 at 4 GeV/c

Development of 12x12 HAPD+electronics is underway

The major remaining issue

cf) Talks by P.Krizan, S.Korpar, T.Sumiyoshi, I.Adachi, A.Gorisek

“Focusing”

“Defocusing”

n1 n2 n1<n2

n1 n2 n1>n2

“Multi-radiator”

RICH2004 Workshop 92004/12/04

TOP Counter Concept Quartz-based RICH counter to detect internally reflected Cherenkov

light (like DIRC at BaBar) But reconstruct the image in (X,TOP) instead of (X,Y).

“TOP” = Time Of Propagation Possible if TOP < 100ps for each arriving photon.

TOP or

NIM A453(2000)331

TOF from IP to quartz baris also used.

RICH2004 Workshop 102004/12/04

“Bar TOP” Counter Proximity focusing in X measurement

Simplified structure and easier installation. Loose requirement for X (~5mm)

Well polished quartz radiator

Photodetection by linear-anode PMT

Flipped images can be resolved by widening

the bar width (>20cm).

K

Simulation2GeV/c, =90 deg.

-ray, had. int.

RICH2004 Workshop 112004/12/04

TOP Counter Design (LoI) Quartz radiator: 40cm x 255cm x 2cm

18 segmentation in r-

Photodetection: MCP-PMT w/ linear anode (5mm) Good time resolution: < 40ps/photon Single photon sensitive up to 1.5T

Number of PMTs (channels) 15 pcs. (60ch) /module 270 pcs. (1080ch) / total

for 1 read-out plane (LoI design) 810 pcs. (3240cn) / total

for 3 read-out planes (present baseline)

R=115~125cm

Z=-72.5~182.5cm

16% x X0

RICH2004 Workshop 122004/12/04

Beam Test w/ Prototype

Test counter

@ KEK PS 2 line 3 GeV/c beamin=in=90 degree

• Clear ring image

• Reasonable time

resolution• Enough bar quality

Demonstration of principle w/ 1m(L)x20cm(W)x2cm(T) R5900-00-L16

RICH2004 Workshop 132004/12/04

Performance of TOP Separation power in two particle species

Single photon resolution time quartz TTS chromatic others

Npe

Group velocity vg=c/ng()

RICH2004 Workshop 142004/12/04

Synthetic fused silica Long transmission Good polishability Radiation hardness

Shin-etsu, “SUPRASIL-P30” T~90% at = 250nm

Polishing accuracy at Okamoto Kogaku Co. (Yokohama)

Quartz Radiator

Quartz polishing accuracy OK

time) measured w/ beam(“Butterfly TOP” w/ R5900-L16)

Bar#1

Bar#2

RICH2004 Workshop 152004/12/04

MCP-PMT (SL10)

1x4 linear-anode MCP-PMT newly developed for TOP readout.

#MCP stage 2

Gain (HV) 2x106 (-3.5KV)

MCP hole dia. 10m

Geometrical collection eff.

50%

#pixel /size 1x4 / 5mmx22mm

Effective area/

Total area64%

Confirmed gain > 106 and TTS = 30ps()In B=1.5T magnetic field.

※ Remaining issues: cross talk, life, deadtime etc.

Under Development

cf) My talk on Tuesday

RICH2004 Workshop 162004/12/04

Expected Performance (1) Design optimization Long propagation distance Large chromatic error. Read-out at both ends better performance in >90deg. Another read-out at =46deg. better performance in <90deg.

4GeV/c,bialkali photocathode Geometrical acceptance loss = 6.3% for 5cm gap.

forwardforward

RICH2004 Workshop 172004/12/04

Performance w/ 3 read-out planes Target: >4 K/ @ 4GeV/c over =35-135deg.

TOP performance (base design)

D* decay events

DIRC performance (from RICH2002)

Want improvementto achieve the target !

~2.5 @ 0.6GeV/c

RICH2004 Workshop 182004/12/04

MCP-PMT with GaAsP Further reduction of chromatic dispersion

→ GaAsP photo-cathode Higher Q.E. (~40%@540nm) at longer wave length → less chromatic error

Light propagation velocity inside quartz

Photon sensitivity at longer wave length shows the smaller velocity fluctuation.

cf) My talk on Tuesday

RICH2004 Workshop 192004/12/04

Performance with GaAsP >4 K/ achievable almost everywhere.

σ～ 30ps

HPK:R3809UGAAP TDC distribution

Measured time responseFor MCP-PMT w/ GaAsP

Input of MC

RICH2004 Workshop 202004/12/04

Robustness against Beam BG Efficiency and fake rate for KID

Bialkali photo-cathode option

Estimated background rate Based on a simulation w/ spent

electron generator (cross checked

by the present TOF rate) Dominated by e+e- conversion hit rate = 44kHz/counter at L=1034

6.8photons/hit/counter ~900kHz-hit/counter at BG x 20 ~80kHz/ch

Stable performance even for 10 times more BG rate of our estimate Our estimate

(/counter)

RICH2004 Workshop 212004/12/04

Issues Photodetection by MCP-PMT

Cross talk, lifetime, deadtime Photocathode selection (bialkali or GaAsP) Readout electronics (TAC-IC)

Further evaluation of performance Geant4 based simulation Reconstruction

Analytic likelihood approach Multi-track capability, boundary effects… Beam BG effects Overall performance for physics processes

Mechanical consideration Glue joint of 40cm wide quartz bars…

cf) My talk on Tuesday

RICH2004 Workshop 222004/12/04

Summary For improving the Belle PID performance in future, we

are developing RICH counters based on new ideas. TOP counter TOP counter for barrel

Detect internally reflected Cherenkov light with precise time measurement; (X,T) readout.

Aerogel-RICH Aerogel-RICH for endcapProximity focusing w/ novel “dual-(multi-) radiator” technique.

Target performance: >4 for the whole B decay region. Target year for upgrade: 2008-9 The major remaining issue is photodetection for both

MCP-PMTMCP-PMT for TOP H(A)PDH(A)PD for Aerogel-RICH

Many Challenges !Many Challenges !Stay Tuned !Stay Tuned !

RICH2004 Workshop 232004/12/04

Beam Test Results ofMulti-Radiator Aerogel-RICH

RICH2004 Workshop 242004/12/04

Butterfly TOPCf) Talk by T.Ohshima at RICH2002

RICH2004 Workshop 252004/12/04

TOP Simulation Evaluate TOP performance and optimize design

Located at current TOF position GEANT base, 1.5T magnetic field Readout (MCP-PMT)

~30ps, 5mm ch. width 80% dead space QE~25%, CE~50% Use only 1st arriving hit in each ch.

Reference design

Efficiency and fake rate : by log likelihood-ratio

cut

Measured TDC dist. including the tailis used as a response function.

RICH2004 Workshop 262004/12/04

Efficiency/fake(LoI design)

• Large drop around =70~80 degree, due to chromaticity.• Need to optimize TOP design (Bar length, width, ch. division, etc.)

P Belle BaBar

Eff.(KK) Fake(K)

Eff.(KK) Fake(K)

2 GeV/c 85% 10% 99% 2%

3 GeV/c 85% 7% 92% 10%

4 GeV/c 85% 6% 87% 11%

cf.) Preset Belle/BaBar

RICH2004 Workshop 272004/12/04

Segmented TOP For long path length,

TOP is increased, but Error due to chromaticity is increased. Optimal path length should exist.

Segmented TOP Various version is tested. For example,

3 times more readoutBut no need for gluing(much easier construction)

RICH2004 Workshop 282004/12/04

“Focusing TOP” 3D information

t, x and vertical angle

Focusing block attached to forward edge.

Matrix readoutFor example, 1cm x 2mm size

with 0.5mm dead space MCP-PMT (TTS~40ps)

at x=0cm

Similar concept to “Ultimate FDIRC”by B.Ratcliff, NIM A502(2003) 211

RICH2004 Workshop 292004/12/04

Fake/Efficiency w/ Focusing Very good separation (= ultimate performance)! Require additional development of

Photodetectors w/ matrix anode ~10mm(X) x ~2mm(Y) High density high resolution timing readout O(105)

98%

2%

RICH2004 Workshop 302004/12/04

Multi-anode MCP-PMT w/ GaAsP ?

The timing performance has been checked with single channel MCP-PMT sample.

According to HPK, Can be made. Effecive area ratio (cathode area/package) may be smaller.

Need clarify Life. Dark counts Cost ?

HPK Data

RICH2004 Workshop 312004/12/04

R&D for Readout ASIC Time-to-Analog Converter Time resolution <~20ps. Double overlap gates Less dead time (~100ns). 0.35 CMOS process.

H.Nakano, T.Iijima (Nagoya)H.Ikeda, I.Adachi, S.Nishida (KEK)T.Sumiyoshi (TMU)

40MHz CLOCK

INPUT

GATE1

GATE2

AOUT1

AOUT2

75ps

125ps

T1

T2

V1 = K x T1

V2 = K x T2

“TAC-IC” Concept

RICH2004 Workshop 322004/12/04

Focusing DIRCcf) Talk by A.DrutskoyAt Hawaii WS

RICH2004 Workshop 332004/12/04

50ps TOF Finer segmentation faster electronics

to cope with the increasing rate.