july 28, 2003- mechanical design of the cell - m. konno, univ. of tsukuba 1 1.introduction...
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July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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1. IntroductionRequirements
2. Details description Design parameters, Cell Design AerogelPMTBox & LidLED Calibration System etc…
3. Performance – KEK test beam, Run3 prototype4. Summary
Mechanical Design Review of the Cell
Aerogel Upgrade Review
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Requirements- Refractive index : n=1.01 – P threshold- Light yield : >10 p.e. – Resolving power- Uniformity of the light yield : Needed. – Easy handling - Occupancy in AuAu collisions : <10% – S/N
1. Introduction
PID in high p-> Cherenkov radiation
Low refractive index-> Silica aerogel
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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1-1 Aerogel Location : W1 Sector
(South side)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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RED: AerogelYELLOW: Integration sphereGREEN: PMT
1-2 Detectors Overlook
z (beam) d
irecti
on
azimuthal angle vertex
particle track
- 4.6m from vertex- Coverage ; 3.9 m along z
15 deg. in phi
160 segments
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Basic Design Parameters
- Single Cell Box Design- Integration Cube Type (Aerogel;12cm, Integration;9cm)- Cell size : 11 x 23 cm2
- Cerenkov radiator : Silica Aerogel (SP-12M, Matsushita)- Refractive index : n=1.0114 +/- 0.0008- PMT : R6233-01HA (Hamamatsu)- Integration Cube for Uniformity of the light yield- Reflector : DRP Reflector (Goretex)- Radiation Lengths
2. Details description
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-0 Cell Design
Reflector (Goretex)
Aerogel
PMT
- Aluminum Box- 0.8mmt- Black Epoxy Joint of the plates Light protection
Integration Cube
- Photo-detection with 2 PMTs- Aerogel part (12cm)- Integration Cube (air, 9cm)- Inner surface covered with Reflector
Efficient light collection ; Reflector Uniformity of the light yield ; Integration Cube
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-1 Silica Aerogel
Silica Aerogel• SP-12M (Matsushita, Japan)
• Refractive index : 1.0114 +/- 0.0008
• Size : 112.5 x 112.5 x 11.0 mm^3
• Density : 40 mg/cm^3
• Transparent
(64% @ 400nm, 88% @ 550nm for 10mmt )
• Hydrophobic
• Long term stability proved by KEK-Belle.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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PMT R6233-01HA (Hamamatsu)- 3-inch diameter large- Gain : >10^7 at –1500V high gain (Single p.e. peak observed)- Q.E. : 30 % high Q.E.-Dark Current : 2nA low noise
at –1500V(wo/ PreAmp)
1 pe
0 pe
2 pe
2-3 PMT
- Calibrated with LED pulser- Typically ~ 8 p.e. for β=1
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-3 PMT Base
HV divider with modification- High Gain compared to the standard (*1)- Thinner material
- Less space- Less power (330 mW@1500V) than the standard (*2)
Note *1 : “2-2-1-1-1-1-1-1” => “1-1-1-1-1-1-1-1”
Note *2 : 330k-ohm => 680k-ohm
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-3 PMT Base (Heating test)
Due to heat dissipation from the divider resistance,the temperature inside the box increased by only ~3 degree.
No-ventilatedHV = -1.5kV
Gas flow is not necessary particularly for cooling.
Measurement
Calculation
Heat calculation is consistent with the measurement. (see Apped-A of CDR)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-3 PMT Base (HV test)
-3.2kV for 10 hours
- Electric non-conductance
Measurement items
No smoke, No heat, No electric sparks
- Long-sustained stability
- Idling current
PMT Base is well-working and stable.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-4 Mu-metal shield (Probing and Test)
B-field at the place where the aerogel counters will be installed ; 2~8 Gauss.
Uniform field
Thickness & Size of the mu-metal shield has been optimized using Helmholz Coil.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-4 Mu-metal shield (Test Results)
Enough Shielding Solution ;0.5mm thick, 80mm long.
- 0.2mm-thick shield is not enough even with 120 mm long.- 40mm-long shield is not enough even with 0.5mm thick.
Normalized ADCTDC Sigma Number of p.e.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-5 Reflector (Selection)
Reflector #peAttenuation
Length [cm]
Goretex 11.78 6.5±0.3
Lumirror 10.2 6.9±0.4
Tetratex 9.8 6.3±0.4
Tyvek ( Double ) 9.1 5.8±0.2
AluminizedMylar
5.3 4.4±0.2
BlackPaper 2.0 2.6±0.1
Distance from PMT
Goretex is the best.
(n=1.017)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
15Wavelength [nm]
5000x SEM of DRP®
Reflector
2-5 Reflector (Properties)
-DRP Reflector (“Goretex”)- High diffuse and reflective- PTFE (0.5mmt)- Reflectance > 99%
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Drawing)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Details)
ReV.C
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Production)
According to the drawings, Boxes have been produced in Dubna.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Shipping to BNL)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Lid with PMTs)
(Run3 prototype)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-6 Box (Inner Box)
- Mylar film for Support - Goretex sheet lined- Silica Aerogel loaded
Inner Box loaded into Aluminum Box
- Aerogel is Very fragile- Careful handling needed
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-8 LED Calibration System
Numbers- 1 PPG- 3 Drivers- 20 Dividers- 160 LEDs
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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ADC
TDC
( ~ 10 p. e.)PMT signal
Gate
Information of chargeInformation of charge
Information of timeInformation of time
(Blue LED source)
2-8 LED Calibration System (Test Result)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-9 Gas Flow
Requirements- Gas delivery system- Clean gas- Light tight and air tight- Low flow rate
Purposes- Purging outgas -- While Aerogel is hydrophobic,
some chemical vapor might damage it.- Non-flammability -- For safety. Aerogel is very expensive.- Cooling -- Indeed, temperature rise can be ignored (~3 deg).
Gas connector with black color (Light protection needed)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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2-10 Table of Radiation Lengths
MaterialThickness
[cm]
Radiation
Length [cm]
Radiation
Length [%]
Aerogel 12.0 539.6 2.24
Aluminum 0.08 8.9 0.89
Goretex 0.05 15.8 0.32
G10 0.20 16.4 1.22
Mylar 0.01 31.1 0.03
Mu-metal 0.05 1.5 3.33
PMT Glass 0.20 12.4 1.61
PMT Base 0.20 16.4 1.22
Total - - 10.89
Overall Lrad ~ 19.2%
PISA
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Particle selection by TOF(2GeV/c, positive)
3. Performance – KEK test beam
- Clear separation of protons and pions observed.- Amount of photons other than Are
ogel Cherenkov is small.
Pions~6.6 p.e./PMT
Protons~0.4 p.e./PMT
π
Kp d
(n=1.0114)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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It is Cherenkov Emission.
2
22
2max1
1p
pm
nNN
Light yield vs Momentum (n=1.017) Light Yield vs Refractive index
PHENIX Aerogel n=1.0114
3-1 Cherenkov emission in Aerogel
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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X
Beam
(0,0)
15cm
15cmPMT1PMT2
Y
Y
X
Beam
(0,0)
11.5cm
21cm
PMT1
PMT2
Y
X
Beam
(0,0)
22cm
12cmPMT1PMT2
Aerogel
PMT PMT
BEAM
Air12cm
12cm
12cm
AerogelPMT PMT
BEAM
12cm
12cm
3-2 Cell geometry
(n=1.017)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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λa
bs
λ sct
BEAM
beam datasimulation
3-3 Optical Simulation - Understanding -
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Y
X
Beam
(0,0)
23cm
11cmPMT2PMT1
3-4 Integration Cube Type – Final prototype -
Positional Uniformity
of the light yield
Gap between aerogel tiles
(Aerogel;12cm, Integration;9cm)
(n=1.0114)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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• Not significant difference observed.
• Easy to stack with the Integration Cube Type.
3-5 Counter orientation
•~10% diff. Between upstream/downstream, •Due to diffusive nature of aerogel
PMTs upstream
PMTs downstream
(n=1.0114)
(Aerogel;12cm, Integration;9cm)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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3-6 Timing information
Scope image
- Propagation time : ~ 7 ns (t=0 is defined as the time of PMT hits.)- Max. 2 ns difference observed between PMT1 and PMT2.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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3-7 Background Rejection (1)
By using the timing and amplitude of signals, events in hitting PMT can be distinguished.
Not only with the tracking, PMT hit is self detectable.
(By One PMT)
~7 ns
Aerogel Hit
PMT Glass Window HitTDCADC
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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3-7 Background Rejection (2)Hit PMT (blue)Opposite PMT (yellow)
By using the timing and amplitude of signals, events in hitting PMT can be distinguished.
Not only with the tracking, PMT hit is self detectable.
(By Pair PMTs of the same box)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Boxes – built in DUBNA, Russia (JINR, A.Litvinenko)
Aerogel, PMT’s, Bases – Tsukuba
Final Assembly – M.Lenz at BNL
3-8 Run 3 – prototype test (1)
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Coincidence probability : 56 % (=111/199)
LED
Physics (coincidence)
Physics (uncorrelated) TDC97
TDC99 TDC99
TDC97111 cnts 199 cnts
197 cnts
3-8 Run 3 – prototype test (2)
• Aerogel Cherenkov Counter works well.
• Waiting for pp production to see track association with other tracking detector.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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4. Summary
Integration Cube Type (Aeroegl;12cm, Integration;9cm)
We use the Mu-metal shield which is 0.5mm thickness and 80mm length.
As reflector, Goretex is the best choice.
LED is used to Calibrate PMTs in the counter.
Gas flow is not necessary particularly for cooling, but might prevent chemical vapor from damaging aerogel.
The overall radiation length of the ACC is about 19.2% by PISA simulation.
We have very uniform response of the light yield with Integration Cube Type.
By using the timing and amplitude of signals, events in hitting PMT can be
distinguished.
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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*1 ; Voltage distr. (1-1-1-1-1-1-1-1)
Appendix - PMT (Parameters)
Sp
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Appendix - PMT Base
July 28, 2003 - Mechanical Design of the Cell - M. Konno, Univ. of Tsukuba
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Appendix - Connectors & Cables
Connectors (Nylon)- Signal transmission- HV Supply- LED for Calibration
Cables- RG174/U (PMT Base -> PreAmp)- HV Cable- UL-E108898 (LAN cable, cat.5)
Flammability ratings ; UL 91V-0 UL 94V-0
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