Fermi National Accelerator Laboratory EXTRUDED SCINTILLATOR STRIPS FOR

Fermi National Accelerator Laboratory EXTRUDED SCINTILLATOR STRIPS FOR MINERVA Anna Pla-Dalmau Fermilab Victor Rykalin NICADD, Northern Illinois University Minerva Collaboration Meeting August 13 -15, 2004

FNAL-NICADD EXTRUSION FACILITY

FNAL-NICADD EXTRUSION FACILITY POLYMER FEEDER DOPANT FEEDER POLYMER DRYER OUTPUT: MELT PUMP Scintillating pellets Scintillator bars EXTRUDER CONVEYOR DIE • In-line continuous process: • Less handling of raw materials • Line under nitrogen atmosphere: • Drying under nitrogen • Each piece of equipment is purged • Precise metering of feeders • Twin-screw extruder (better mixing) • Melt pump offers steady output • Control instrumentation

EXTRUSION TOOLING FOR MINERVA

EXTRUDED SCINTILLATOR STRIPS FOR MINERVA

SCINTILLATOR CHARACTERISTICS

SCINTILLATOR CHARACTERISTICS LIGHT YIELD RATIO: 1. 64 (TYVEK / NO-TYVEK) Attenuation Length L=27. 06 cm Attenuation Length L=29. 42 cm

SCINTILLATOR PROFILE STRIP SIZE: 32. 1 mm by 16. 6 mm – lip ~ 31 mm by 16. 6 mm - round HOLE SIZE: 2. 5 -3 mm by 1. 5 -2 mm (OVAL) STRIPS AVAILABLE: - 50 cm long & round hole 44 STRIPS - 1. 5 mm FIBER 38 STRIPS - <1. 5 mm FIBER - 100 cm long & oval hole 50 - 100 STRIPS

SCINTILLATOR PROFILE ROUND CORNERS VS. LIP AT THE BASE

CURRENT STATUS • Reasonable triangle shape – Slightly small – Bowed / indented base – round corners – “Flatter” base – lip • The die and/or the calibrator would need to be modified. • Large and oval hole • The pin needs to be changed. • Strips show arching (upwards) at the ends – Stress caused by uneven cooling in the part

NEXT STEP • Feedback from MINERVA – What is needed in the scintillator strips? – Will strips be glued? – What is the size of the fiber? • Back to the die maker to address current problems – Likely to require additional funding • FNAL number for the drawing • Purchase polystyrene and dopants • One more run “as is” to test air knife