서준석, KPS, 2005.10.22
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R&D of Extruded
Plastic Scintillator
서 준석
김 동희, 양 유철, 오 영도, 장 성현, 조 기현, KHAN Adil,
MIAN Shabeer Ahmad (경북대학교)
서준석, KPS, 2005.10.22
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1.Motivation
2.Extruded Plastic Scintillator
3.Current R&D Status
4.Summary and plan
Contents
서준석, KPS, 2005.10.22
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Probably the most commonly used organic scintillator
in nuclear & high energy physics
Advantage
Fast response time (≤3ns)
Ease of manufacture
Versatile: plates, fibers, tiles, blocs
But
Plastic Scintillator
서준석, KPS, 2005.10.22
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Machining of raw tile
Covering with reflector
$25/tile → $80/kg
~$300/sheet
서준석, KPS, 2005.10.22
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Disadvantage
High cost :
$40/kg-$60/kg (2000)
$80/kg (2004)
$100/kg (2005 ?) → $??/kg (2006)
Machining of the raw sheets
→ significantly add to the final detector cost & time
Not for very large detector
like MINOS detector (300,000 kg scintillator)
Plastic Scintillator
서준석, KPS, 2005.10.22
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To lower costs ⇒ Extruded Scintillator ☺
Advantages:
Use commercial polystyrene pellets → cheap
Processing flexibility
→ Manufacture of essentially any shape with reflector
Experimental applications:
MINOS for two detectors: 300 ton of scintillator strips
D0 for two preshower detectors
Star for a shower max. detector in the em. end-cap calorimeter
MINERVA for an active target
ILC calorimeter
And more … maybe for your future detector
서준석, KPS, 2005.10.22
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Prototype for EM Calorimeter
One Layer : Tungsten 20cm X 20cm X 0.3cm
(example) Scintillator 1cm X 20cm X 0.2cm X 20 strips
Total : 30 Layers
(~ 26 Xo)
Basic Configuration of a ILC Calorimeter
Tungsten
Scintillator
서준석, KPS, 2005.10.22
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Component: Polystyrene pellets + Dopants (primary & secondary)
Dopants
• Primary dopants (UV-emitting)
PPO(2,5-biphenyloxazole) , PT(p-Teraphenyl)
1-1.5% (by weight) concentration
• Secondary dopants (blue-emitting)
POPOP(1,4-bis(5-Phenyloxazole-2-yl)benzene),
bis-MSB(4-bis(2-Methylstyryl)benzene)
0.01-0.03% (by weight) concentration
Extruded Plastic Scintillator
서준석, KPS, 2005.10.22
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Plastic Scintillator – how does it work ?
Excitation of base plastic by radiation
Faster energy transfer
Emit UV ~340nm
Absorb UV photon
Emit blue ~400nm
10-8 m
10-4 m
photon
photon
Detector (PMT, photo diode …. )
Base plastic
PPO (~1%)
POPOP(~0.05%)
Use WLS fibers as readout
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Die and Materials
Die profile
Mixture of dopants
Polystyrene : 6 kg
PPO : from 1.0 %
POPOP : from 0.03%
• This was originally for MINOS tile
• We start to produce this tile for a reference
• produce and compare the light yield withreference tile
서준석, KPS, 2005.10.22
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Extrusion Process
Producedat MiSungChem. co.In Korea
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Current R&D Status
At first, the pure polystyrene bar was produced
without PPO, POPOP
The mechanical process has been established
At second, PPO and POPOP were mixed up with polystyrene
The 1st scintillator had been produced.
Many scintillator strips have been produced with differentsituations since then.
different amount of PPO and POPOP, nitrogen and/or vacuum,
various mix-up methods etc.
서준석, KPS, 2005.10.22
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Mechanical establishment of tile
Produce polystyrene bar without PPO & POPOP for mechanical establishment
TiO2 was co-extruded to make reflector for test.
Excellent bars were produced assure mechanically
Then, 1st batch came with PPO and POPOP.
Progress
서준석, KPS, 2005.10.22
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Production of Scintillator bar
서준석, KPS, 2005.10.22
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Comparison of transparency
Reference
samples
Polystyrene
(only) bar
1st batch
Oxidation made the sample opaque
because of production in air.
Recent batch
Progress
서준석, KPS, 2005.10.22
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Pulse Height (1st batch)
Our scintillator bars (5 samples)
<ADC counts> = 225.9 24.9
Reference scintillator bars(5 samples)
<ADC counts> = 534.8 56.9
Relative Light Yield of the first samples
shows 42.3% of reference samples
Our sample(1st batch)
Reference sample
ADC counts
ADC counts
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Light Yield
Progress
Reference tile to be 100% light yield
Relative Light Yield
Progress
서준석, KPS, 2005.10.22
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Light Yield (currently the best one)
Reference Sample
New Sample
Relative LightYield of newsamples shows(93±8)%
of referencesamples’ one.
서준석, KPS, 2005.10.22
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Position Scan
Scan across the fiber
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Summary and Plan
First Polystyrene bar produced with PPO and POPOP
The mechanical process has been established
Light yield measured for new and reference samples
Currently the best samples show (93±8) % light yield
of the reference sample
We will change the die to produce “thin” scintillator
for Tile/W calorimeter thickness : 2-3 mm , width : 1-2 cm
hole : 1.2 mm
for WLS fiber
서준석, KPS, 2005.10.22
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backup
서준석, KPS, 2005.10.22
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Preparation of test samples
WLS fiber
서준석, KPS, 2005.10.22
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Scintillator test setup
Typical cosmic ray
From reference sample + WLS
FAN
IN-OUT
Logic
unit
Gate
Generator
100 ns
Delay
VME
readout
Disc
5 reference samples and newsamples with the same geometricalshape and size were used tocompare the light yield