development of rich counters toward the kekb/belle upgrade

Development of RICH Counters Toward the KEKB/Belle Upgrade

Toru IijimaNagoya University

March 3, 2008@ BINP, Novosibirsk, Russia

10th International Conference on Instrumentation for Colliding Beam Physics (INSTR08)

ContentsIntroductionQuartz-based RICH

Time-Of-Propagation CounterAerogel-based RICH

Proximity Focusing Aerogel RICHSummary

Toru Iijima, INSTR08 @ BINP, Novosibirsk 22008/03/03

I cannot cover all the proposed idea, developments for super-KEKB.

e-

8.0GeVe+

3.5GeV

2.6m

1.2m1.5T

Super-Belle PID (an option) To cope with increased background (present x ~20) To improve the performance.

Target: > 4s at 4 GeV/c Novel Ring Imaging Cherenkov Counters

w/ advanced radiator & photo-detection technologies


Tight space limitation Barrel: DR = 10-20cm Endcap: DZ = 28cm

TOP CounterAerogel-RICH

There are also other options: Focusing-DIRC, TOF.

Key Technology: Radiators Quartz (fused Silica)

Accurately polished to preserve the Cherenkov angle info. after many internal reflections. Polish: 0.5nm Figure: 0.6mm Squareness: ±0.3mrad


Silica aerogelImproved transmission by new recipie. LT > 40mm for n=1.04-1.05

Hydrophobic for long term stability

Interferogram

0

10

20

30

40

50

60

1.02 1.04 1.06 1.08Refractive index

Tran

smisi

on le

ngth

(mm)

Refractive index

Tran

smss

ion

leng

th ◆2005-2006▲2004■Before 2003

Transmission length at = 400nm

Aerogel Useful for Sports ? Aerogel is very fragile, but have the highest withstand load/

mass. Aerogel powders are put in carbon fibers to increase the

stiffness without increasing its mass.


http://tennis.dunlop.co.jp/gear/racket/aero/index.html

Key Technology: Photodetectors High gain, Q.E., C.E.

Good time resolution

Good effective areain magnetic field (1.5T)PMT MCP-PMT HPD / HAPD Geigermode-APD

Gain >106 ～ 106 ～ 103

X10 ～ 100 w/ APD

～ 106

Quantum Eff. ～ 20%, ～ 400nm (bialkali) > 50%, ～ 600nm

Collection Eff. 70% 60% 100% 50%

Time resolution ～ 300ps ～ 30ps ～ 150ps

Depends on readout<100psTo be checked

B-field immunity × △ Depends on angle ○

Problems lifetime Noise, size6Toru Iijima, INSTR08 @ BINP, Novosibirsk2008/03/03

MCP-PMTMicro-channel-plate PMT

HAPDHybrid Avalanche Photodiode

Geigermode-APD

Time-Of-Propagation Counter


Accurately polished quartz & precision timing

Quartz based RICH


Use of total internal reflection in accurately polished quartz bar.A concept was invented by B.Ratcliff et al.

DIRC (Detector of Internally Reflected Cherenkov light)NIM A479(2002)1

TOP (Time Of Propagation) CounterNIM A453(2000)331

Focusing DIRC/TOP

TOP or

(X, Y)

(X, TOP)

(X, Y, TOP)Measurement coordinates

Cherenkov ring imaging using timing information

92008/03/03

TOP counter

Difference of path length Difference of time of propagation (TOP)

150~200ps from TOP + TOF from IP with precise time resolution (s~40ps) for each photon

d-ray, had. int.

Simulation2GeV/c, q=90 deg.

Toru Iijima, INSTR08 @ BINP, Novosibirsk

Toru Iijima,

INSTR08 @ BINP, Novosibi

rsk10

Design Quartz: 255cmL x 40cmW x 2cmT

Cut at 47.8deg. to reduce chromatic dispersion

Multi-anode MCP-PMT Good time resolution (<~40ps), Linear array (5mm

pitch) Three readout planes

MCP-PMT

2008/03/03


1x4 MCP-PMT (SL10)

1x4 linear-anode MCP-PMT for TOP readout. Developed under collab. with Hamamatsu

Photonics.#MCP stage 2

Gain (HV) 2x106 (-3.5KV)

MCP hole dia. 10mm

Geometrical collection eff. 50%

#pixel /size 1x4 / 5mmx22mm

Effective area/Total area

64%

Confirmed gain > 106 & TTS=30ps(s) in B=1.5T magnetic field.

122008/03/03

Chromatic Dispersion

GaAsP photo-cathode ( alkali p.c.) Higher quantum-efficiency at longer wavelength → less chromatic error

Light propagation velocity inside quartz

Photon sensitivity at longer wavelength shows the smaller velocity fluctuation.

Variation of propagation velocity depending on the wavelength of Cherenkov photons


pedestal

single photon peak

Gain ～0.64×106

Target structure

132008/03/03

GaAsP photocathodew/ Al protection layer

2 MCP layers with f=10mm hole Wave form, ADC and TDC distributions for single photon

Enough gain to detect single photo-electron Good time resolution (TTS=35ps) for single p.e.

GaAsP MCP-PMT

Single p.e.0.5ns/div20mV/div

TTS ～ 35ps


GaAsP MCP-PMT(2) QE uniformity

Check QE distribution by moving stage Good performance in recent sample

Multi-alkali p.c. without Al protectionTo improve correction efficiencya) 3-layer MCP-PMT; test with BINPb) Low gain operation to suppress ion feedback


YH0053 YH0056 YH0057 YH0081

PD

MCP-PMT

SpotX

Y

Monochrometer

Old sample New sample

Performance with GaAsP K/p separation power

GaAsP photo-cathode + >400nm filter, CE=36%

3.5s K/p for 4 GeV/c, q=70 ﾟ2008/03/03 15Toru Iijima, INSTR08 @ BINP, Novosibirsk

162008/03/03

Focusing TOP Remaining chromatic effect makes

~100ps fluctuation for TOP. Use dependence of Cherenkov

angle to correct chromaticity Focusing system to measure qc

qc y position Reconstruct ring image from 3D

informations (time, x and y).

Focus Mirror

))(1(cos=)( 1βλnλθ c

ー

Rotate PMT

Side view

Mirror image

( ) ( ) ( ) /g p pn n dn d


Focusing Mirror Check accuracy of mirror

shape Peak position of spherical

mirror wrt. quartz edge By 3D measurement system

at Nagoya-univ Correct with the result of flat

planes 0.33±0.30±0.20mm outside

from bar edge Acceptable in simulation Cross check by

interferometer in Okamoto optics work, inc.


Pin gauge

Mirror

Lens

182008/03/03

Performance of Focusing TOP K/p separation power

GaAsP photo-cathode(+>400mm filter), CE=36%

4.3s separation for 4GeV/cToru Iijima, INSTR08 @ BINP, Novosibirsk

TOP Configuration Summary

Focusing type can reduce the dead space and remove middle PMT.


optionK/pi separation

performance at 70 deg, 4GeV/c

critical issues

3 readout + multi-alkali 2.8 sigma (Make

prototype)3 readout +

GaAsP 3.5 sigma PMT productionPMT lifetime

Focusing + multi-alkali

2.5 sigma 4.0 sigma if improved

eff. PMT lifetime

Focusing + GaAsP 4.2 sigma PMT production

PMT lifetime

Proximity Focusing Aerogel RICH


Highly transparent aerogel + Photon Imaging

Proximity Focusing Aerogel RICH Aerogel radiator (n~1.05,

~2cm) + photodetector (Dx ~ 5mm)

Proximity focusing geometry No mirror complex. Suitable for collider and space

experiments. >4s K/p for 0.7 < p < 4.5

GeV/c@ 4GeV/c, q(p)=310mrad.

q(p)-q(K)=23mrad.

Distance between aerogel to photodetector = 200mm.

Track Incident angles = 17-34deg.

2008/03/03 21Toru Iijima, INSTR08 @ BINP, Novosibirsk

Beam Test w/ Flat Panel PMT 4×4 array of H8500 52.5mm pitch 84% effecive area. 1024 channel Two MWPC for tracking

NIM A521(2004) 367

Typical Results

s0 = 14.8 mrad. <Npe> = 6.2

Want more photons ! 14.8 5.96.2trackmrad mrads 4s K/p

@ 4GeV/c22Toru Iijima, INSTR08 @ BINP, Novosibirsk2008/03/03

RICH with Multiple RadiatorsNIM A548(2005)383

Conventional4cm thick aerogeln=1.047

sc=22.1mradNpe=10.7

Multiple Radiators

sc=14.4mradNpe=9.6

2 layers of 2cm thick n1=1.047, n2=1.057

Demonstration of principle 4×4 array of H8500 (85% effective area)

23p/K separation with focusing configuration ~ 4.8s @4GeV/c

2008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk

PID Capability Based on a likelihood approach. Simulation w/ the level of bkg. expected at Super-Belle. Focusing radiator improves PID for p>3GeV/c

dE/dx (CDC) Kaon Cherenkov Threshold

2008/03/03 24Toru Iijima, INSTR08 @ BINP, Novosibirsk

Improvement by TOF ?

252008/03/03

144ch HAPD Newly developed under

collaboration with Hamamatsu Photonics.

4 APD chips (6x6pixel/chip) 5x5mm2 pixel 64% effective area High gain: O(104)

-10kV15~25mm

e-

Multialkari photocathode

Pixel APD


1 p.e.

2 p.e.

3 p.e.4 p.e.

Total gain ~ 5x104

S/N = 8-15for single p.e.

1 p.e.

2 p.e.

3 p.e.

Test at bench

HAPD Readout ASIC

Toru Iijima, INSTR08 @ BINP, Novosibirsk 262008/03/03 26

Features: High density front-end electronics (100K

channels) High gain with low noise amplifiers Deadtime-less readout scheme (pipeline)

Basic parameters Rohm 0.35mm CMOS) Shaping time = 0.3-2.0ms VGA = 1.25-20 18 channels/chip 3mW/channel

□4.93[mm]

HAPD status 3 working HAPD samples at hand. Additional couple of samples soon.


HAPD samples (+ASIC) are being tested.

Plan to have a beam test with aerogel+HAPD in this month.

HPAD test w/ ASIC

Response to single photon irradiationSum of 36 channels

ch1 ch4

ch12 ch2

14

212

Effects due to electric field distortion at edge Need be tested in the magnetic field.

Other possibilitiesMCP-PMTHigh gain (~106)Good time resolution(~50ps/p.e.)

Stable operation.Need

Smaller pore size (25m <10m) Better collection eff. Lifetime ?

28

Light collector□3~5mm (IN)□1-2mm(OUT)

G-APD□1~3mm

Cherenkov Photons17deg max. for n=1.05

BURLE 85011-501

Geiger-mode APD High gain(~106) High Q.E.(>50%) B-field immunity

independent of the direction.

Concerns High noise rate

(~200KHz/mm) Size (~1x1mm2 3x3mm2) Radiation damage ?


RICH w/ TOF Capability Possible PID improvement in low momentum

region. Two timings can be used;

“Ring hit” : Cherenkov photons from aerogel.sphoton ~ 60ps strack ~ 60ps/sqrt(9) =20ps

“Window hit”: Cherenkov photons from glass window of PMT

strack ~10ps possible (from the TOF R&D @ Nagoya). Aerogel

PMT

IP

DTOF1(K-p)

D ~ 0.2m

DTOP

L ~ 1.8m

Ring HitDTOF1 + DTOP

Window HitDTOF2 w/ L+D


Beam Test w/ BURLE MCP-PMTDecember 2005 @ KEK-PS T2

30

Multi-anode MCP-PMTBURLE 85011-50113 channels readout by

FTA820 amplifier (ORTEC) L-edge discri (Phillips)KC3781A TDC (Kaizu works)

Start counter: HPK R3809U MCP-PMT 1cm quartz radiatorStart time resolution = 10ps

Cherenkov photon

from aerogel

Cherenkov photonfrom windowMWPC MWPC

Aerogel radiator

1.045 1.053

TDC count(/25psec)

Time resolution for “window hits” (Time walk corrected)

s = 34.3±1.1ps

p p

s= 36.2±1.3ps

TOF test w/ beam p and p (2GeV/c)


P (GeV/c)

RICH +TOF

1.0 2.9s ~4s2.0 4.7s ~5s

Improvement in K/p separation

Impact of PID improvement

2008/2/28

Toru Iijima,

INSTR08 @ BINP, Novosibi

rsk31 31

FWD BRL

dE/dx NA As good as Belle

A-RICH A-RICH+TOF

TOF, dE/dx NA –33% –33% –30% –30%

TOF NA –34% –33% –29% -29%

As good as Belle –1% 0%

(definition) +5% +5%

TOP opt.0 +47% +50% +57% +58%

TOP opt.2 +70% +72% +82% +82%

Completely different world with excellent

PID detectors!

No upgradeBAD

UpgradeGOOD

No upgradeBAD

UpgradeGOOD

FWD BRL

As good as Belle

A-RICH

As good as Belle

0% (definition) +6%

TOP opt.2 +16% +23%

B0gr0g

B0gp+p

Luminosity loss / gain

Summary RICH detectors, based on Quartz and Aerogel, are being

developed for the Super-KEKB/Belle

Key technologies; Radiators: Accurately polished quartz

Highly transparent aerogel Photodetectors: MCP-PMT / HAPD / Geiger-mode APD

Ideas to overcome performance limitations TOP counter: chromatic dispersion GaAsP, focusing-TOP Aerogel RICH: emission point uncertainty multiple-

radiator

Prototype detectors with the newly developed potodetectors will be tested in beams by summer 2008. Finalization of detector design.

322008/03/03Stay Tuned.Toru Iijima, INSTR08 @ BINP, Novosibirsk

Backup slides

33Toru Iijima, INSTR08 @ BINP, Novosibirsk2008/03/03

Chromaticity Detection time depending on the wavelength of

Cherenkov photons Worse time resolution

Worse ring-image separation

Propagation velocity depending on l in the quartz bar

352008/03/03

Focusing TOP (2) Dqc~1.2mrad over sensible range Dy~20mm (~quartz thickness)

We can measure dependence and obtain good separation even with narrow mirror and readout plane, because of long propagation length.

Not need focusing block

1850mm

Virtual readout screen 22mm x 5mm matrix

Focusing mirror

Dqc~1.2mrad


36

Possible configuration Detector type

3-readout type Optimized propagation length Simple configuration less technical issue Simple ring image easy reconstruction

Focusing type Correct chromaticity 2/3 PMTs

Cost Small dead space Easy to replace PMTs because of no middle PMT

Complicated ring image Need noble reconstruction method May need more simulation study to check robustness

Focus Mirror

37

Possible configuration Photo-cathode of MCP-PMT

Multi-alkali Almost established production Enough lifetime

GaAsP Better efficiency at longer

wavelength Need more production R&D and

lifetime test Multi-alkali without Al

protection layer on MCP (option)

Better efficiency (x1.6) Almost established production,

but need some modification to improve lifetime (3-layer MCP, operation with lower gain, etc.)

GaAsP MCP-PMT

Single Photon Angle ResolutionMain contributions come

from Detector granularity

Emission point uncertainty

All other contributions (not fully understood yet)

8as mrad

4[ds mrad/ cm] d[cm]

6rs mrad

asds

Emission point uncertainty dominates @ d > 2cm38Toru Iijima, INSTR08 @ BINP, Novosibirsk2008/03/03

39

Beam Test Results ofMulti-Radiator Aerogel-RICH


TOF in Aerogel-RICHL = 1.8m, D=0.2m, Normal incidence

- 0.05000

0.00000

0.05000

0.10000

0.15000

0.20000

1.0 2.0 3.0 4.0 5.0Momentum (GeV/ c)

DTIM

E/DT

OF(n

s)

DTOF1(K- pi)DTOP(K- pi)DTIME(K-pi)DTOF2(K- pi)

DTOF2(K- p) with "Particle Hit"

DTIME(K- p) with "Ring Hit" = DTOF1+DTOP

DTOF1(K- p)DTOP(K- p)

Worth for studying !1.5GeV/c

2GeV/c 4GeV/c

Ring Hit -- 147ps 37psWindow Hit

323ps 184ps 47ps402008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk

Time resolution for Ring Hits Obtained time resolution for Cherenkov photons from

aerogel agrees well with the value from the bench tests. Resolution for the full ring (Npe~10) would be about 20ps.

TDCBURLE-TDCSTART COUNTER

Distribution of the hits on MCP-PMT (13 channels were readout).

Corrected distribution using the track information.

s= 51.4±1.1ps


development of rich counters toward the kekb/belle upgrade

Documents

mradtoru iijima

gevctoru iijima

aerogel richtoru iijima

aerogel powders

s separation

focus mirror

d informations time

key technology