PID for super Belle (design consideration)

PID for super Belle(design consideration)

K. Inami (Nagoya-u)

- Barrel (TOP counter)- Possible configuration- Geometry

- Endcap (Aerogel RICH)- Photo detector options

- Barrel-Endcap

2

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

3

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

4

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.

5

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

6

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

7

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

8

Performance 3-readout type + GaAsP photo-cathode

>400nm filter, Correction Eff.=35%

3.5 K/ for 4 GeV/c, =70 ﾟ

9

Performance Focusing type + GaAsP photo-cathode

>400nm filter, Correction Eff.=35%

4.2 K/ for 4 GeV/c, =70 ﾟ

10

Performance Focusing type + Multi-alkali

>350nm filter, Correction Eff.=60%

3.5 K/ for 3 GeV/c, =70 ﾟ

Because of complicated ring image

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

19

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.

20

Geometry Possible layout with overlap

Need 50cm-width quartz bar