Development of RICH Counters Toward the KEKB/Belle Upgrade
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Transcript of 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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 32008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 42008/03/03
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.
Toru Iijima, INSTR08 @ BINP, Novosibirsk 52008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 72008/03/03
Accurately polished quartz & precision timing
Quartz based RICH
Toru Iijima, INSTR08 @ BINP, Novosibirsk 82008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 112008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 142008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk
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.
Toru Iijima, INSTR08 @ BINP, Novosibirsk 172008/03/03
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.
Toru Iijima, INSTR08 @ BINP, Novosibirsk 192008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk 202008/03/03
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
Toru Iijima, INSTR08 @ BINP, Novosibirsk
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.
Toru Iijima, INSTR08 @ BINP, Novosibirsk 272008/03/03
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
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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 ?
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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 ?
2008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk
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
292008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk
Beam Test w/ BURLE MCP-PMTDecember 2005 @ KEK-PS T2
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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)
2008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk
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
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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
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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
Toru Iijima, INSTR08 @ BINP, Novosibirsk
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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
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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
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Beam Test Results ofMulti-Radiator Aerogel-RICH
2008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk
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
412008/03/03 Toru Iijima, INSTR08 @ BINP, Novosibirsk