J.S. Suh The Second Korean ILC Workshop Plastic Scintillator Detector for ILC Jun-Suhk Suh KNU/CHEP

J.S. Suh The Second Korean ILC Workshop High Energy Particle Plastic Scintillator WLS(Wavelength Shifting) fiber SiPM Plastic Scintillation Detector

J.S. Suh The Second Korean ILC Workshop Common layout for ECAL and HCAL

J.S. Suh The Second Korean ILC Workshop 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= cm). –Total radiation length ~26X 0. Dimensions (to be optimized) –Strips (1cm x 20cm) –Small tiles (4cm x 4cm)

J.S. Suh The Second Korean ILC Workshop 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

J.S. Suh The Second Korean ILC Workshop 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 ?

J.S. Suh The Second Korean ILC Workshop 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

J.S. Suh The Second Korean ILC Workshop Cast plastic scintillator sheets - high cost :

J.S. Suh The Second Korean ILC Workshop Cast plastic scintillator sheets - high cost :

J.S. Suh The Second Korean ILC Workshop Cast plastic scintillator sheets - high cost :

J.S. Suh The Second Korean ILC Workshop 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 high particulate matter content in the polystyrene pellets The rapid cool-down cycle leaves the final material stressed. 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 → 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

J.S. Suh The Second Korean ILC Workshop Plastic Scintillator Component: Polystyrene pellets + Dopants (primary & secondary)  Optical characteristics of polystyrene e.g.) STYRON 663 ( Dow Chemical) valueTest Haze 1% (ASTM D1003) Refractive index (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) % (by weight) concentration  Production : Extrusion

J.S. Suh The Second Korean ILC Workshop Extruder Scintillator

J.S. Suh The Second Korean ILC Workshop Examples of extrusions

J.S. Suh The Second Korean ILC Workshop Experimental applications  D0: for preshower detectors Triangular extrusions (6mm wide & 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)

J.S. Suh The Second Korean ILC Workshop Profile of a Scintillator Strip 5 10

J.S. Suh The Second Korean ILC Workshop 1 cm Size of a scintillator strip 20 cm

J.S. Suh The Second Korean ILC Workshop WLS fiber Plastic Scintillator A front view of scintillator strip

J.S. Suh The Second Korean ILC Workshop 0.25 mm TiO 2 Reflective Cap Plastic Scintillator WLS fiber Scintillator strip with reflective cap

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

J.S. Suh The Second Korean ILC Workshop Possible schedule (very preliminary) –R&D of dopants (primary & secondary) –R&D of groove (length, depth & shape) –R&D of Light yield –Design optimization (length, width, Thickness) –Production of an ECAL test module –Tests with cosmic-rays –Test beam studies of the ECAL test module “standalone” “standalone” –Test beam studies in combination with HCAL