TOP group, N-lab Contents 1.Introduction 2.R&D of TOP
counter components 3.Performance test of prototype 4.R&D of
HAPD for A-RICH counter 5.Summary 2 B @ Nov 5, 2009
Slide 3
TOP group, N-lab 1. INTRODUCTION 3 B @ Nov 5, 2009
Slide 4
TOP group, N-lab 1. Our Motivation Upgrade of Belle PID system
Current PID system of Belle /K separation power : 3 Barrel: TOF +
ACC End cap: ACC 4 B @ Target Performance 3 4 (0.6 < p < 4
GeV/c) Upgrad e (ACC: Threshold type Aerogel Cherenkov Counter)
Barrel: TOP counter End cap: Aerogel RICH Belle-II Current system
2.6m 1.2m e - 8.0GeV e + 3.5GeV 1.5T ForwardBackward Install here
Nov 5, 2009
Slide 5
TOP group, N-lab 2. Principle of TOP counter (1) DIRC
(Detection of Internally Reflected Cherenkov light) technique
Cherenkov radiator + screen (photo-detector matrix) Cherenkov light
propagate to terminal of quartz with total reflection Ring image is
detect as parabola 5 B @ Imaging with quartz Require large screen
For same momentum, velocity of /K is different different ring
images Nov 5, 2009
Slide 6
TOP group, N-lab 2. Principle of TOP counter (2) 6 B @ TOP(Time
Of Propagation) counter Cherenkov radiator + time sensitive screen
Position (x, y) Position + time (x, t) Very compact & simple
TOP counter measures TOF + RICH High performance expected! time
includes TOF information 1.18m TOF TOP Nov 5, 2009 z y x
Slide 7
TOP group, N-lab 3. Expected Performance in Belle-II /K
separation power 4 for 2
TOP group, N-lab 2. Photo-detector Requirements Gain : 1.010 6
TTS : 20%@=400nm Usable in B -field 12 B @ (Micro Channel Plate)
Only photo-detector satisfies requirements MCP-PMT Square type
MCP-PMT Co-development with Hamamatsu Photonics Channel ~400 m ~10
m Channel ~10m, Bias angle of MCP : 13Usable in B-field Nov 5,
2009
Slide 13
TOP group, N-lab 3. MCP-PMT R&D Output charge distribution
13 B @ Pedestal Output of single photon Gain 1.010 6 Single photon
detection OK Nov 5, 2009
Slide 14
TOP group, N-lab 4. MCP-PMT R&D 14 B @ =34.20.4ps QE
24%@400nm QE>20%@=400nm OK transit time [25ps] counts wavelength
[nm] QE[%] TTS 40ps OK Single photon irradiation Nov 5, 2009
Slide 15
TOP group, N-lab 3. PERFORMANCE TEST OF PROTOTYPE 15 B @ Nov 5,
2009
Slide 16
TOP group, N-lab 1. Beam Test 16 B @ Detection of ring image
Obtain N( ), number of detected photons par track TTS measurement
Items to confirm electron beam 2GeV/c MCP-PMT Timing Counter MWPC2
MWPC1 Veto counter Trigger Counter TOP Counter Subtract em-shower
events Beam trajectory t0 determination Setup of beam test at Fuji
test beam line Nov 5, 2009 Performed in Jun. & Dec. 2008
Slide 17
TOP group, N-lab 2. Result : ring image Proper action of total
system of TOP counter is confirmed 17 B @ ch Ring image (data) Ring
image simulation transit time[25ps] Nov 5, 2009
Slide 18
TOP group, N-lab 3. Result : number of detected photons N()
consistency confirmed Slightly different remaining shower event 18
B @ Number of detected photons/events arbitrary Nov 5, 2009
Slide 19
TOP group, N-lab 1 st 2 nd 3 rd 1 st 2 nd 3 rd 4. Result :
transit time distribution We confirmed consistency of transit time
distributions for beam test & simulation 19 B @ TTS 1 st peak
Data76.02.0 [ps] Simulation77.72.3 [ps] Beam irradiation point (
875mm ) Beam irradiation point ( 875mm ) 875mm 915mm quartz 3 rd 2
nd 1 st ch29 transit time[25ps] [photons] transit time[25ps]
datasimulation Nov 5, 2009
Slide 20
TOP group, N-lab 4. R&D OF HAPD FOR A-RICH 20 B @ 2.6m 1.2m
e - 8.0GeV e + 3.5GeV 1.5T ForwardBackward Aerogel RICH Nov 5,
2009
Slide 21
TOP group, N-lab 1. Aerogel RICH counter 21 B @ Nov 5,
2009
Slide 22
TOP group, N-lab 2. HAPD R&D Hybrid structure Vacuum tube
APD (5x5mm 2 matrix) Bialkali photocathode ~10 4 total gain
Confirmed Single photon detection Available in 1.5T B-field Current
issue Radiation hardness (neutron) study Photocathode study Nov 5,
200922 B @ 73mm Single photon irradiation Photo-detection in
Magnetic field
Slide 23
TOP group, N-lab 5. Summary & Issues Our Motivation:
upgrade of PID system Target performance: separation power 3 4
Idea: barrel TOP, end cap Aerogel RICH TOP counter New idea of
RICH: Position(x, y) Position(x) + time(=TOF+RICH) Basic
performances are confirmed with prototype Issue Structure,
reconstruction code, lifetime of PMT, readout, etc HAPD R&D
Performances are available for ARICH Issue Neutron hardness, high
QE photocathode study 23 B @ Nov 5, 2009
Slide 24
TOP group, N-lab BACKUP 24 B @ Nov 5, 2009
Slide 25
TOP group, N-lab Belle-II experiment Our target of development
: Belle-II experiment 25 B @ Belle detector Higher statistics
Higher luminosity ~40 B-factory Super B-factory Higher accuracy
Belle detector upgrade e + e - asymmetric collider e + : 3.5GeV e -
: 8.0GeV e + e - (4S) BB /K-ID is important for flavor tagging Nov
5, 2009
Slide 26
TOP group, N-lab History of R&D Butterfly TOP 26 B @ Nov 5,
2009
Slide 27
TOP group, N-lab timing 1m assumption Performance
Parameterization Important parameters : N det, photodetector 27 B @
: Difference of TOF +TOP for /K 60ps : TTS of TOP counter :
Detected photons/track 20 : TTS of photo-detector 40ps : Chromatic
dispersion 1m propagation in quartz: 50ps 25ps Can suppress with
cut filter Separation power : Nov 5, 2009
Slide 28
TOP group, N-lab Chromatic Dispersion Chromatic dispersion 28 B
@ group velocity of light [m/ns] wavelength [nm] number of detected
photons Typical wavelength distribution of detected photons Typical
wavelength distribution of group velocity of light Restricts TOP
TTS This is because refraction index has wavelength dependence Nov
5, 2009
Slide 29
TOP group, N-lab Suppression of Chromatic Dispersion Wavelength
cut 29 B @ Group velocity of light Number of Cherenkov photons
Transmittance of wavelength cut filter 350nm Suppression of
chromatic dispersion with 350nm wavelength cut filter wavelength
cut TTS improve N det decrease fine tune chromatic 50 25ps Nov 5,
2009
Slide 30
TOP group, N-lab 1. Radiator Quartz (fused silica) Size
91540020 (mm 3 ) Weight 16kg Flatness < 1.2m/m Surface roughness
5 Refractive index 1.45 Co-development with Okamotokougaku 30 B @
Nov 5, 2009
Slide 31
TOP group, N-lab Construction of Prototype 31 B @ Al honeycomb
Quartz Al honeycomb Spring loaded polyathetal head
plunger40/surface Distortion of frame is absorbed by spring Cross
section of radiator part 23mm 46 mm Al honeycomb support Core
density 0.037g/cm 3 Thickness 10mm Surface plate 0.3mm Al Sag <
80m Quartz flatness in Frame
TOP group, N-lab Summary for TOP Counter TOP counter is very
compact & simple detector based on TOF + RICH technique
Radiator propagates Cherenkov light without distortion Position(x,
y) Position(x) + time (= TOF + TOP) Target performance of TOP
counter >4 for 0.6 < p < 4GeV/c Key parameters Number of
detected photons Prototype of TOP counter has been constructed We
confirmed basic performances of prototype with following
parameters: 38 B @ QuartzMCP-PMT Flatness : 1.2 m/mGain : ~1.0 10 6
Roughness : 5 TTS : < 40ps Shape accuracy : 10QE : > 20%@=
400nm Nov 5, 2009