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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. POLYMER FEEDER. DOPANT FEEDER. POLYMER DRYER.
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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
POLYMER FEEDER DOPANT FEEDER POLYMER DRYER MELT PUMP EXTRUDER DIE CONVEYOR FNAL-NICADD EXTRUSION FACILITY OUTPUT: Scintillating pellets Scintillator bars • In-line continuous process: • Less handling of raw materials • Precise metering of feeders • Twin-screw extruder (better mixing) • Melt pump offers steady output • Control instrumentation • Line under nitrogen atmosphere: • Drying under nitrogen • Each piece of equipment is purged
SCINTILLATOR CHARACTERISTICS LIGHT YIELD RATIO: 1.64 (TYVEK / NO-TYVEK) Attenuation LengthL=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