Plastic Scintillator Detector for ILC

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

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

3. Common layout for ECAL andHCAL The Second Korean ILC Workshop

4. 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) The Second Korean ILC Workshop

5. Wolfram Scintillator 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 The Second Korean ILC Workshop

6. 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-costplastic scintillator ? The Second Korean ILC Workshop

7. 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 The Second Korean ILC Workshop

8. Cast plastic scintillator sheets - high cost : The Second Korean ILC Workshop

9. Cast plastic scintillator sheets - high cost : The Second Korean ILC Workshop

10. Cast plastic scintillator sheets - high cost : The Second Korean ILC Workshop

11. 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 The Second Korean ILC Workshop

12. Plastic Scintillator Component: 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 The Second Korean ILC Workshop

13. Scintillator Extruder The Second Korean ILC Workshop

14. Examples of extrusions The Second Korean ILC Workshop

15. 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) The Second Korean ILC Workshop

16. Profile of a Scintillator Strip 5 10 The Second Korean ILC Workshop

17. Size of a scintillator strip 20 cm 1 cm The Second Korean ILC Workshop

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

19. Scintillator strip with reflective cap Plastic Scintillator 0.25 mm TiO2 Reflective Cap WLS fiber The Second Korean ILC Workshop

20. Extrusion Process 1

21. 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

22. 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 The Second Korean ILC Workshop