TOP R&D status - phys.hawaii.edusuperb/2005/slides/detector2/satoh/... · alkali is observed for...
Transcript of TOP R&D status - phys.hawaii.edusuperb/2005/slides/detector2/satoh/... · alkali is observed for...
TOP R&D statusNoriaki Sato (Nagoya Univ.)
2005.04.20 Super B-Factory Workshop in Hawaii
Status
MCP-PMT R&D
Summary
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.1/22
TOP CounterRing Imaging Cherenkov counterwith precise measurement of the Time Of Propagation (and TOF)
Quartz Radiator & Photon Detector
Reconstruct ring image from (X, TOP )
TOP = L/vzg(λ)
vg(λ): The group velocity of light
⇒ Chromatic dispersion:One of the main subject for Performance
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.2/22
R&D Status at the Last Workshop
Test Counter
Confirmed the principle by the test counter.
Quartz-bar studyBasic study was already done.Need very good polishing accuracy ∼
◦A
Performance study by simulationLight propagation in quartz Photon detection by MCP-PMT
MCP-PMT R&D: Current Main Subject and Today’s Main TopicMCP-PMT is the possible candidate of photon detector to satisfy thefollowing requirements:
Good time resolution: σ � 40 psPosition sensitive: � 5 mmSingle photon sensitive under B = 1.5T
⇒ We’ve developed SL10 with HPK : Basically Good Performance!A homework: cross-talk
Other issues: Geometry and support structure, readout elec.should be studied and working now
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.3/22
Base DesignRadiator: Quartz bar of 255cmL × 40cmw × 2cmT × 18 units in φsegmented at θ = 46◦ to reduce chromatic dispersion error
Photon detector: Multi-anode MCP-PMT at three readout planesSL10 (R&D w/ HPK) : 5mm pitch linear array, σTTS ∼ 30 ps.
!!!!
Forward SL10
Shown later in detail ⇒Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.4/22
TOP Performance2GeV/c, 90◦ π KPerformance Study by MC simulation.
Separation Power
S =∆TOP + ∆TOF
σtime× √
Npe
σtime � σpolish ⊕ σTTS ⊕ σchro.
Target > 4σ@4 GeV/c :does not been achived
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.5/22
MCP-PMT with GaAs/GaAsPGaAs/GaAsP photo-cathode (SL10: multi-alkali)Higher Q.E. → Increase Npeat longer wave length → Reduce chromatic dispersion
QE
0
5
10
15
20
25
30
35
40
45
50
100 200 300 400 500 600 700 800 900 1000
Multi-AlkaliGaAsPGaAs
Wavelength(nm)
Q.E
.(%
)
Group velocity
0.17
0.175
0.18
0.185
0.19
0.195
0.2
0.205
0.21
100 200 300 400 500 600 700 800 9001000lambda(nm)
gro
up
vel
oci
ty(m
/ns)
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.6/22
MCP-PMT PerformanceTTS of MCP-PMT w/ GaAs/GaAsP may be worse due to the thickness ofphoto-cathode. =⇒ should be checked
multi(bi)-alkali(HPK/BINP) ∼ 100◦A
GaAsP (HPK) ∼ µm
GaAs (BINP) ∼ µm: Just delivered
Measured MCP-PMTHPK BINP
photo- multi-alkali multi-alkalicathode GaAsP (GaAs)
MCP ch φ 6µm# of MCP 2stage
anode single
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.7/22
MCP-PMT Performance: ADC/TDCADC: Gain ∼ 1.0 × 106
Good performance asthe same level of multi-alkali is observed forGaAsP photo-cathodeMCP-PMT.
TDC: σT T S ∼ 30psmulti-alkali
0
2000
4000
6000
-20 -10 0 10 20TDC(time walk correction)
σTTS ≈ 32ps
GaAsP
0
1000
2000
3000
-20 -10 0 10 20TDC(time walk correction)
σTTS ≈ 31ps
0
2000
4000
6000
-20 -10 0 10 200
2000
4000
6000
-20 -10 0 10 20TDC(time walk correction)
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.8/22
TOP Performace w/ GaAsP PMT
> 4σ@4GeV/c can be achieved!
⇒ multi-anode MCP-PMTwith GaAsP cathode
(SL10 w/ GaAsP)
Other Issues? ⇒ Lifetime
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.9/22
Lifetime testTwo types MCP-PMT: w/ & w/o Allayer
HPK(R3809U), BINPMutli-alkali photo-cathode
Al preventaion layerBlock feedback ions from MCP tophoto-cathodeMake photo-cathode lifetimelongerC.E. decreases by 60%
MeasurementMulti-photons irradiate by LED.Efficiency is measured with singlephoton by pulse laser(@400nm)
e- Al prevention layer
MCP plates
Anode plate
laser
LED
Filte
rFi
lter
MCP-PMTs
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.10/22
Lifetime: Q.E. of HPKMeasurement Q.E. lifetime
∼ 700 mC/cm2 output forone year operation.(BG rate ×20)
Rapid efficiency drop forPMT w/o Al layer⇒ Need Al layer
Life-Time -Output Charge vs Relative QE-
0.2
0.4
0.6
0.8
1
1.2
1.4
0 10 20 30 40 50 60 70 80Output Charge (mC/cm2)
Rel
ativ
e Q
E
AL no(R3809U-50 YA0071)
AL yes(R3809U-50 CT0790)
~1month
Setup was changed.
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.11/22
Lifetime: Q.E. of BINP
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 100 200 300 400 500 600 700 800
noAl (11)
Al_low (32)
Al_high (35 )
hpk6_noAl
hpk6_Al
1kHz_noAl(6)
1kHz_Al(38)
Output Charge (mC/cm )2
Rela
tive
QE (
%)
w/o Al
w/ Al
1year operation
Need Al-layer, too.Lifetime ∼ 300mC/cm2 even w/ Al layer⇒ Need effort (Vacuum level)
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.12/22
Lifetime: Gain
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 100 200 300 400 500 600 700 800
noAl (11)
Al_low (32)
Al_high (35)
hpk6_noAL
hpk6_Al
1kHz_noAl(6)
1kHz_Al(38)
Output Charge (mC/cm )2
Relative Gain
Gain is almost stable (> 80%@700mC/cm2)If gain drops, we can raise high voltage up to recover it.
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.13/22
Rectanglular PMT: SL104ch linear array MCP-PMT
Photo cathode mutli-alkaliMCP ch φ 10 µm# of MCP 2 stage
# pixel/size 1×4 / 5mm×22mmGeometrical C.E. 50%Eff. area(2cmT) 77%
Gain (HV) 2× 106 (−3.5 kV)σT T S(HV, B) ∼30ps (−3.5 kV, 1.5T)
Gain > 106, σT T S ∼ 30ps in B =1.5 T: Confirmed
SL10
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.14/22
Cross-talkTime resolution becomse worse due to cross talk of neighbor signals.
To reduce cross talk, divide electrodes on MCP.
S/N is improved from ∼ 5 to ∼ 10.
S/N ∼ 5
S/N ∼ 10
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.15/22
Cross-talk: TTSMeasurement L.E.Discri.
C.F.Discri.
σT T S � 100ps at 1.5ns delay⇒ Improvement w/ CFD : σT T S ∼ 40ps
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.16/22
Summary and Future PlanSummary
Performance StudyNeed to reduce chormatic dispersion error⇒ segmented bar, GaAsP photo-cathode MCP-PMT with GaAsPphoto-cathode⇒ ∼ 4σ π/K separation @4GeVNeed to test of lifetime.Lifetime testNeed Al layer at least, it is not enough, though.Cross-talkDivide electrodes, CFD → TTS ∼ 40ps
Future PlanLifetime of MCP-PMTNeed more effort. Test of the GaAsP photo-cathode.BINP’s GaAs MCP-PMTPerformance check Lifetime test
Other issuesReadout elec., Support structure, · · ·: working now
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.17/22
Personal AnnouncementI have another talk on the τ -physics in thePhysics Parallel V, tommorow afternoon.Please come and listen!
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.18/22
Personal AnnouncementI have another talk on the τ -physics in thePhysics Parallel V, tommorow afternoon.Please come and listen!Although I don’t finish the preparation yet.
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.18/22
MCP-PMT Performance: Raw SignalHPK multi-alkali GaAsP
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.20/22
Readout elec.: TAC-ICRequirements
Time resolution � 20psby Time to Analog ConverterLow dead time ∼ 100 psLimited double overlap gateSmall size & Multi channel
Test production (by VDEC)
TAC with comparator, CFDWell work with 40MHz clock!Time resolution: ∼ 200 ps⇒ should be improved for
the next test production
Status of TOP Counter, 2005.04.20 Super B-Factory Workshop – p.21/22