pid for super belle (design consideration) k. inami (nagoya-u) - barrel (top counter) - possible...
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PID for super Belle(design consideration)
K. Inami (Nagoya-u)
- Barrel (TOP counter)- Possible configuration- Geometry
- Endcap (Aerogel RICH)- Photo detector options
- Barrel-Endcap
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2.6m
1.2m
e-
8.0GeVe+
3.5GeV
TOP counter Aerogel RICH
- PID () detectors- Inside current calorimeter- Use less material and locate near calorimeter TOP and Aerogel RICH counters
- both Cherenkov ring imaging detectors
Super B detector
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TOP counter Quartz: 255cmL x 40cmW x 2cmT
Focus mirror at 47.8deg. to reduce chromatic dispersion
Multi-anode (GaAsP) MCP-PMT Linear array (5mm pitch), Good time resolution (<~40ps) Measure Cherenkov ring image with timing information
MCP-PMT
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TOP counter Measure Position+Time
Compact detector!
Linear array PMT (~5mm)Time resolution ~40ps
~2m
K
Simulation2GeV/c, =90 deg.
~200ps
Different opening angle for the same momentum Different propagation length(= propagation time)
+ TOF from IP works additively.
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Chromatic dispersion
Due to wavelength spread of detected photons, propagation time becomes worse.
Longer propagation length Improve ring image difference
But, decrease time resolution. Optimal propagation length.
Light propagation velocity inside quartz
Variation of propagation velocity depending on the wavelength of Cherenkov photons
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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 wavelengt
h Need more production R&D and lifeti
me test Multi-alkali without Al protection l
ayer on MCP (option) Better efficiency (x1.6) Almost established production, but n
eed some modification to improve lifetime (3-layer MCP, operation with lower gain, etc.)
GaAsP MCP-PMT
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Performance 3-readout type + GaAsP photo-cathode
>400nm filter, Correction Eff.=35%
3.5 K/ for 4 GeV/c, =70 ゚
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Performance Focusing type + GaAsP photo-cathode
>400nm filter, Correction Eff.=35%
4.2 K/ for 4 GeV/c, =70 ゚
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Performance Focusing type + Multi-alkali
>350nm filter, Correction Eff.=60%
3.5 K/ for 3 GeV/c, =70 ゚
Because of complicated ring image
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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 productionPMT lifetime
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Geometry
18 counters in r-
Al wall (1mmt)
Quartz
Similar with BaBar DIRC Narrow space for support structure
Only 16mm between quartz bar Gaps in 10% dead space
~1cm weak region from bar edge
BaBar DIRC
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Geometry (2) Possible overlapped layout
Need 50cm-width quartz bars ( 40cm-width) R1080 of inner radius ( R1150 for previous)
Difficulty for support structure
Complicated space
Need simulation study Requirement from physics
Check S/N with etc. PID performance
confirm dead space Effect to outer detector
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Aerogel RICH Radiator
Aerogel (n~1.05) Multiple radiator option
Set suitable radiator index By stacking the radiators,
Increase Nphoton without deteriorating ring image
Photon detector HAPD, MCP-PMT, MPPC etc. Single photon detection
~400nm Cherenkov photon Operational under
~1.5T magnetic field High hit rate
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Photon detector option HAPD
Good result from test bench with ASIC readout Stability? Need more production R&D
MCP-PMT Good TTS for TOF information
<20ps TOF resolution Good ability for low momentum PID
Need lifetime estimation
SiPM/MPPC Good stability, Enough gain and TTS Need large effective area or light guide to make
~5x5mm2 anode Need gated readout because of high dark count
(<~MHz)
New
Old20mmMPPC
MCP-PMT
HAPD
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Barrel - Endcap Need to minimize dead space
TOP needs PMT region at bar end. We can cover with aerogel radiator.
To detect Cherenkov lightemitted to outside,we should set mirrors atAerogel RICH outer cylinder.
Simulation study to estimateseparation power
Some R&D with mirrors
PMT
Drift chamber
Barrel Calorimeter
Forward endcap Calorimeter
Radiator
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Summary Photon detector is still main issue for designing.
GaAsP/Multi-alkali photo-cathode MCP-PMT for TOP HAPD, MCP-PMT and MPPC with light guide for Aerogel RICH
TOP configuration Focusing type + GaAsP photo-cathode MCP-PMT (>4.2)
Option; Multi-alkali with efficiency improvement Geometry of TOP bars
~10% dead space along Overlapped TOP geometry Check requirements from physics
Barrel – Endcap Need design study of outer boundary of Aerogel RICH
Mirror to correct the out-going Cherenkov photons
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Focusing TOP
1850mm
Virtual readout screen 22mm x 5mm matrix
Focusing mirror
c~1.2mrad
Use dependence of Cherenkov angle to correct chromaticity
Angle information y position Reconstruct Ring image from 3D information
(time, x and y). c~1.2mrad over sensitive range y~20mm (~quartz thickness)
We can measure dependence and obtain good separation even with narrow mirror and readout plane, because of long propagation length.
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Geometry Possible layout with overlap
Need 50cm-width quartz bar