Scintillator based muon upgrade / BELLE Super B Factory Workshop In Hawaii 19-22 Jan 2004, Honolulu,...
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Transcript of Scintillator based muon upgrade / BELLE Super B Factory Workshop In Hawaii 19-22 Jan 2004, Honolulu,...
Scintillator based muon upgrade / BELLE
Super B Factory Workshop In Hawaii19-22 Jan 2004, Honolulu, Hawaii
1. Scintillator strip option2. Geiger photodiodes (SiPM & MRS APD)3. Scintillator tile option4. First tests at BELLE5. Conclusions
Outline
M.Danilov, D.Liventsev, R.Mizuk, P.Pakhlov, V.Rusinov, E.Tarkovsky, I.Tikhomirov, T.Uglov (ITEP Moscow)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 2
Scintillator Strip Geometry (1)
System consists of ~17k scintillator strips with WLS fiber readout.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 3
Scintillator Strip Geometry (2)
Max. strip length ~2.8m.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 4
Light Yield in MINOS Scintillator Strips1cm x 4cm, 1.2mm Y11 fiber
5p.e. correspond to efficiency of about 99%.Mirroring of fiber far end increases light yield by a factor 2 (at the end).
N p
.e.
Distance along strip, m
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 5
Problems with PM Readout
• Complicated transportation of light with clear fibers.• Difference of gain between different pixels (up to factor 3).• Cross-talk ~ 5-10% → ghost clusters (at acceptable level).
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 6
SiPM
For further details see:«Advanced study of SiPM»http://www.slac.stanford.edu/pubs/icfa/fall01.html
2ns
2mV
SiPM main features:• Sensitive size 1x1mm2 on chip 1.5x1.5 mm2
• Gain 2106
• Ubias~50V• Recovery time ~ 100 ns/pixel• Number of pixels: 576-1024• Insensitive to magnetic field• Dynamic range ~103/mm2
R 50
h
pixels
Ubias
50V
Al
DepletionRegion 2m
substrate
ResistorRn=400 k
20m
42m
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 7
0
10
20
30
40
0 1 2 3 4 5 60
5
10
15
20
Ubreakdown
=48V
operating voltage
one pixel gain (exp. data) one pixel gain (linear fit)
One
pix
el g
ain
M, 1
05
Overvoltage U=U-Ubreakdown
, V
detection efficiency (=565nm)
Det
ectio
n ef
ficie
ncy
, %
Gain & Efficiency of SiPM vs. Overvoltage
Efficiency = QEgeom
geom~0.3
(B.Dolgoshein et al. )
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 8
SiPM Cross-talk
Pixel Gain, 105
Inte
rpix
el C
ross
-tal
k (>
1 to
1 r
atio
)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 9
Efficiency vs. Wavelength
200 300 400 500 600 700 8000
20
40
60
80
QE•geom
SiPM
PMT XP2020Q number 40979(according to Philips Photonics)
APD EG&G C30626E (NIM A428 (1999) 413-431)
room temperature
QE
, %
Wavelength , nm
(B.Dolgoshein et al. )
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 10
Emission Spectrum of Y11 WLS Fiber
Measured at distances 10cm, 30cm, 100cm and 300cm from source.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 11
SiPM Noiserandom trigger
1p.e.2p.e.
3p.e.Ped.
noise rate vs. threshold
Optimization of operatingvoltage is subject of R&Dat the moment.
1p.e. noise rate ~2MHz.threshold 3.5p.e. ~10kHzthreshold 6p.e. ~1kHz
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 12
Scan of Strip Using Cosmics Setup
LED cosmics
∑ PoissXtalk·G(x0+i·Δx,0+1 ·√i) Center of strip, N pixels (peak) = 9.7
groove depth 2.5mm
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 13
Scan of Strip Using Cosmics Setup (2)
Poisson mean for MIP at normal incidence
Strip 200x2.5x1cm3
MC: light yield for 4x1cm2 stripwill be ~25% smaller.
In the middle of 280x4x1cm3 strip we expect ~ 9p.e.
With threshold 4.5p.e. • noise rate <10kHz• efficiency 98%• average efficiency >99%
Similar detector - MRS APD - with smaller x-talk and similar efficiencyis under investigation now. Expect efficiency >99.5% with noise <1kHz
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 14
Metal-Resistor-Semiconductor APD (CPTA, Moscow)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 15
MRS APD Cross-talk
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 16
MRS APD Efficiency vs. Wavelength
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 17
Scintillator Tile Geometry (1)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 18
Scintillator Tile Geometry (2)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 19
Light Yield from 16x16x0.5cm3 Tile with Circular WLS
Y11 MC 1mm fiber, Vladimir Scintillator
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 20
Experience of CALICE (1)
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 21
Experience of CALICE (2)
Amplitude distributions for LED and for triggered 90Sr signals in 5x5x0.5cm3 tile.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 22
Experience of CALICE (3)
Light Yield from 129 Minical tiles.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 23
Measurement of Scintillator Sensitivity to Neutron Background at BELLE
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 24
Neutral KLM Clusters with Matching ECL Originating from Background
cosθ
MC (no continuum)
BB + bg
BB only
dataexp 13
(lab.system)
• Random KL background exists already at present background rates even if coincidence between two layers is required.
• With scintillator KLM even one layer clusters could be considered for KL reconstruction.
cosθ
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 25
Conclusions
1. Most probably RPC KLM will not be able to work good enoughat higher luminosity in end-cap region.
2. Scintillator technique can be used to build reliable, very efficient and simple in operation KLM.
3. Many parameters should still be optimized.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 26
Tests of Different Shapes of Grooves
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 27
Amplitude Dependence on Temperature
T=+9.5oC
T=+14.6oC
T=+20.1oC
T=+25.3oC
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 28
Light Yield from 5x4x1cm3 Scintillator with Straight Central Groove (1mm Y11 WLS fiber, β-source)
80
90
100
110
120
130
140
150
0 2 4 6 8
Series1
groove depth, mm
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 29
Tests of Different WLS Fibers and Scintillator Types
WLS
Y11 MC1 mm
BC-92 SC1 mm
5*5 cmcircle
5*5 cmdiagonal
1 1
0.46 0.58
To understand different light loss withBC-92 for circular and straight grooveslight loss in a fiber loop was tested:
-source
scint
PMR=22mm
Y11 has 6% light loss; BC-92 -27% (with respect to a straight fiber)
I. Comparison of Y11 and BC-92.
BICRON-408 scintillator gives x1.5 more light than Russian scintillators.It is order of magnitude more expensive. Therefore we use Russian scintillator.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 30
Light Yield of Individual MINOS Sc. StripsThere is a substantial difference in individual strip responce.However all strips give more than 3p.e. at 3m.
Nonuniformity across strip is about 5% only for 4cm x 1cm strips.
Super B Factory Workshop In Hawaii, 19-22 Jan 2004, M.Danilov 31
Problems with RPC
• Hit rate at 1200mA/800mA– Barrel: ~ 0.02 Hz/cm2 (~same as
no beam case)– Endcap: ~ 0.1 Hz/cm2
• Extrapolation to x20 beam current (assuming linear)– Barrel: at most ~ 0.4 Hz/cm2 at
most a few % efficiency drop, acceptable
– Endcap: ~ 2 Hz/cm2 significant efficiency drop, something must be done