j.s. suh 2004.12.28. the second korean ilc workshop plastic scintillator detector for ilc jun-suhk...

2004.12.28. 2004.12.28. The Second Korean ILC Workshop The Second Korean ILC Workshop J.S. Suh J.S. Suh

Plastic Scintillator Detector foPlastic Scintillator Detector for ILCr ILC

Jun-Suhk Suh Jun-Suhk Suh

KNU/CHEPKNU/CHEP

2004.12.282004.12.28 The Second Korean ILC Workshop The Second Korean ILC Workshop J.S. SuhJ.S. Suh

High Energy Particle

Plastic Scintillator

WLS(Wavelength Shifting) fiber

SiPM

Plastic Scintillation Detector


Common layout for ECAL andCommon layout for ECAL and HCALHCAL


ECAL structureECAL structure

An ECAL super-layer consists ofAn ECAL super-layer consists of– W 3mm + X-strips 2mm +cable 1mmW 3mm + X-strips 2mm +cable 1mm– W 3mm + Y-strips 2mm +cable 1mmW 3mm + Y-strips 2mm +cable 1mm– W 3mm + small tiles 2mm + cable W 3mm + small tiles 2mm + cable

1mm1mm

Effective Moliere radius 18mmEffective Moliere radius 18mm

10 super-layers (30 layers)10 super-layers (30 layers)– Total thickness 18cm (r=210-228cm).Total thickness 18cm (r=210-228cm).

– Total radiation length ~26XTotal radiation length ~26X00..

Dimensions (to be optimized)Dimensions (to be optimized)– Strips (1cm x 20cm)Strips (1cm x 20cm)– Small tiles (4cm x 4cm)Small tiles (4cm x 4cm)


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


Plastic Scintillation Detector

StrengthsStrengths– FastFast response time response time– EaseEase of manufacture of manufacture– VersatilityVersatility

DrawbacksDrawbacks– Relatively Relatively lowlow radiation resistance radiation resistance– HighHigh cost (> $40 per kg) cost (> $40 per kg)

Not good for very large detectors Not good for very large detectors

Is there any Is there any low-costlow-cost plastic scintillatorplastic scintillator ? ?


Low cost plastic scintillator ? (1/2)

CastCast plastic scintillator sheets - high cost : plastic scintillator sheets - high cost : The The lavor-intensive nature of the manufacturing processeslavor-intensive nature of the manufacturing processes

1. The low material need to be 1. The low material need to be highly purehighly pure– Cleaning & assembly of the molds for the polymerization procesCleaning & assembly of the molds for the polymerization proces

s is a detailed-oriented operation s is a detailed-oriented operation → overall effort→ overall effort

2. The polymerization cycle 2. The polymerization cycle lasts for 3-5 dayslasts for 3-5 days– A high temperature treatment to induce full conversion from monA high temperature treatment to induce full conversion from mon

omer to polymeromer to polymer– A controlled ramp-down to room temperature to achieve a stresA controlled ramp-down to room temperature to achieve a stres

s-free materials-free material

3. 3. MachiningMachining of the raw sheets of the raw sheets→ → significantly add to the costsignificantly add to the cost


CastCast plastic scintillator sheets - high cost : plastic scintillator sheets - high cost :


Low cost plastic scintillator ? (2/2)

ExtrudedExtruded plastic scintillator materials - low cost : plastic scintillator materials - low cost : Polymer pellets or powder must be usedPolymer pellets or powder must be used

1&2. Commercial polystyrene pellets are 1&2. Commercial polystyrene pellets are readily availablereadily available→ → Eliminating monomer purification and polymerization chargesEliminating monomer purification and polymerization charges

3. The extrusion process can manufacture essentially 3. The extrusion process can manufacture essentially any shapeany shape

Some disadvantageSome disadvantage Poorer Poorer optical qualityoptical quality than the cast material, because of than the cast material, because of

• the the high particulate matterhigh particulate matter content in the polystyrene pellets content in the polystyrene pellets • The The rapid cool-down cyclerapid cool-down cycle leaves the final material stressed. leaves the final material stressed. → → This stress can lead to non-absorptive optical distortions in the material that degraThis stress can lead to non-absorptive optical distortions in the material that degra

de the attenuation lengthde the attenuation length A way to bypass the short attenuation length problem is A way to bypass the short attenuation length problem is

to extrude a scintillator shape and use WLS fiber readoutto extrude a scintillator shape and use WLS fiber readout

We need more R&DWe need more R&D


Plastic ScintillatorComponent: Polystyrene pellets + Dopants (primary & secondary) Optical characteristics of polystyrene e.g.) STYRON 663 (Dow Chemical)

value Test Haze 1% (ASTM D1003) Refractive index 1.590 (ASTM D542) Transmittance 90% (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


Extruder

Scintillator


Examples of extrusions


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)


Profile of a Scintillator Strip

5

10


1 cm

Size of a scintillator strip

20 cm


WLS fiber

Plastic Scintillator

A front view of scintillator strip


0.25 mm TiO2 Reflective Cap

PlasticScintillator

WLS fiber

Scintillator strip with reflective cap

Extrusion Process 1

Extrusion Process 2All 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 Possible schedule (very preliminary)preliminary)

2004-2005 2004-2005 – R&D of R&D of dopants (primary & secondary)dopants (primary & secondary)– R&D of R&D of groove (length, depth & shape)groove (length, depth & shape)– R&D of R&D of Light yieldLight yield– Design optimizationDesign optimization (length, width, Thickness) (length, width, Thickness)

2005-20062005-2006– ProductionProduction of an of an ECAL ECAL test moduletest module– Tests with cosmic-raysTests with cosmic-rays

2006-20082006-2008– Test beam studies of the ECAL test module Test beam studies of the ECAL test module

““standalone”standalone”– Test beam studies in combination with HCALTest beam studies in combination with HCAL

j.s. suh 2004.12.28. the second korean ilc workshop plastic scintillator detector for ilc jun-suhk...

Documents

ecal test moduletests

extrusion process

scintillator degradationj

hits history

suhpossible schedule

high temperature cycle

additional chance