Transcript Extruded Scintillator

Plastic Scintillator Detector
for ILC
Jun-Suhk Suh
KNU/CHEP
2004.12.28.
The Second Korean ILC Workshop
J.S. Suh
Plastic Scintillation Detector
High Energy Particle
WLS(Wavelength Shifting) fiber
SiPM
Plastic Scintillator
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Common layout for ECAL and HCAL
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
ECAL structure
An ECAL super-layer consists of
– W 3mm + X-strips 2mm +cable 1mm
– W 3mm + Y-strips 2mm +cable 1mm
– W 3mm + small tiles 2mm + cable 1mm
Effective Moliere radius 18mm
10 super-layers (30 layers)
– Total thickness 18cm (r=210-228cm).
– Total radiation length ~26X0.
Dimensions (to be optimized)
– Strips (1cm x 20cm)
– Small tiles (4cm x 4cm)
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Calorimeter R&D
 Prototype Layout
One Layer : Wolfram 20cm X 20cm X 0.3cm
Scintillator 1cm X 20cm X 0.2cm X 20
 Total: 30 Layers
Wolfram
Scintillator
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Plastic Scintillation Detector
Strengths
– Fast response time
– Ease of manufacture
– Versatility
Drawbacks
– Relatively low radiation resistance
– High cost (> $40 per kg)
 Not good for very large detectors
Is there any low-cost plastic scintillator ?
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Low cost plastic scintillator ? (1/2)
Cast plastic scintillator sheets - high cost :
 The lavor-intensive nature of the manufacturing processes
 1. The low material need to be highly pure
– Cleaning & assembly of the molds for the polymerization
process is a detailed-oriented operation → overall effort
 2. The polymerization cycle lasts for 3-5 days
– A high temperature treatment to induce full conversion from
monomer to polymer
– A controlled ramp-down to room temperature to achieve a
stress-free material
 3. Machining of the raw sheets
→ significantly add to the cost
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Cast plastic scintillator sheets - high cost :
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Cast plastic scintillator sheets - high cost :
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Cast plastic scintillator sheets - high cost :
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Low cost plastic scintillator ? (2/2)
Extruded plastic scintillator materials - low cost :
 Polymer pellets or powder must be used
1&2. Commercial polystyrene pellets are readily available
→ Eliminating monomer purification and polymerization charges
3. The extrusion process can manufacture essentially
any shape
 Some disadvantage
 Poorer optical quality than the cast material, because of
• the high particulate matter content in the polystyrene pellets
• The rapid cool-down cycle leaves the final material stressed.
→ This stress can lead to non-absorptive optical distortions in the material that
degrade the attenuation length

A way to bypass the short attenuation length problem is
to extrude a scintillator shape and use WLS fiber readout

We need more R&D
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Plastic Scintillator
Component: Polystyrene pellets + Dopants
(primary & secondary)
 Optical characteristics of polystyrene
e.g.) STYRON 663 (Dow Chemical)
value
Haze
1%
Refractive index
1.590
Transmittance
90%
Test
(ASTM D1003)
(ASTM D542)
(ASTM D1003)
 Dopants
• Primary dopants (blue-emitting)
PT(p-Teraphenyl), PPO(2,5-biphenyloxazole)
1-1.5% (by weight) concentration
• Secondary dopants (green-emitting)
POPOP(1,4-bis(5-Phenyloxazole-2-yl)benzene),
bis-MSB(4-bis(2-Methylstyryl)benzene)
0.01-0.03% (by weight) concentration

Production : Extrusion
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Scintillator
Extruder
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Examples of extrusions
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Experimental applications
 D0: for preshower detectors
• Triangular extrusions (6mm wide & 5.4-6.1 mm high)
• Dopants
Primary dopant : PT (p-Teraphenyl)
Secondary dopant: DPS(trans-4,4’-diphenylstilbene)
 MINOS: 300,000 kg for their detector
• Rectangular profile (41 mm wide, 10 mm high & 2-mm deep groove)
• Dopants
Primary: PPO(2,5-biphenyloxazole)
Secondary: POPOP(1,4-bis(5-Phenyloxazole-2-yl)benzene)
 STAR: will be using extruded scintillator
for a shower maximum detector in em end-cap calorimeter
• Triangular extrusions 10 mm wide & 7 mm high
• Dopants
Primary dopant: PT (p-Teraphenyl)
Secondary dopant: DPS(trans-4,4’-diphenylstilbene)
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Profile of a Scintillator Strip
5
10
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Size of a scintillator strip
20 cm
1 cm
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
A front view of scintillator strip
WLS fiber
Plastic Scintillator
2004.12.28
The Second Korean ILC Workshop
J.S. Suh
Scintillator strip with reflective cap
Plastic
Scintillator
0.25 mm TiO2
Reflective Cap
2004.12.28
WLS fiber
The Second Korean ILC Workshop
J.S. Suh
Extrusion Process 1
Extrusion Process 2
All the work is done at one facility
→ reduces costs
By removing its exposure to another
high temperature cycle → reduces
hits history of the product →
eliminates an additional chance for
scintillator degradation
Possible schedule (very preliminary)
2004-2005
– R&D of dopants (primary & secondary)
– R&D of groove (length, depth & shape)
– R&D of Light yield
– Design optimization (length, width, Thickness)
2005-2006
– Production of an ECAL test module
– Tests with cosmic-rays
2006-2008
– Test beam studies of the ECAL test module
“standalone”
– Test beam studies in combination with HCAL
2004.12.28
The Second Korean ILC Workshop
J.S. Suh