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Fabrication of Quarter-size ScintillatingStrip Muon Detector Planes

Mitch WayneUniversity of Notre Dame

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Motivation

Fabrication of quarter-size planes (1.4m × 2.8m) will exercise all the steps required to make full-sized planesDevelop techniques: splicing, routing, calibration, etc.Provides a benchmark for future development:

• New photodetectors - APDs, VLPCs, etc• New scintillator and/or waveshifting materials

Conserves raw materials – scintillating strips and fiber

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Detector Concept

• Dimensions: 2.2cm x 1.4m x 2.8m• 64 active strips with wave shifting fiber readout

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Production Plan

Two units (S+,S-) with single-ended readout already complete, under test at FermilabTwo units (D+,D-) with double-ended readout nearly completeA few features– Clear readout fiber spliced to waveshifting fiber– All fiber routing internal to the detector– LED calibration of each strip with flat optical panel– Thermally straighten fiber ends– Paint ends of tiles with BC620– Bond WLS in grooves with Epon815,TETA

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Scintillator Strip Testing

28” long Al bar

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photodiode photodiodeUV LED

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Typical good result Poor result, strip discarded

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Fiber preparation

1.2mm Clear waveguide, spooled1.2mm Wavelength Shifter, spooled

Visual inspection with LED on end Measured on cutting templateA clean, razor cut is made with ‘HandiCutter’

All fiber, both clear and waveshiftingis characterized before and after splicing to assure quality

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Fiber testing

Fibers characterized with respect to each otherAcceptance cut is 70% of average for groupLED, photodiode, water couplantThree test runs each

Digitization and readout

photodiode green LED

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Light Test of Waveshifting Fiber for S+

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Fiber number

Aver

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Normalized fiber averagesAverage

44 separate pieces - no rejected fiber

Sigma of ~ 10%

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Thermal Splicing

Splicing machine (U. of Mississippi design) used at Fermilab lab 7

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photodiode UV LED

LED Test of Single-ended Spliced Fibers

Al mirror

Splice covered by protective plastic sleeveDigitization

and readout

Transmission ofspliced fiber used for S+

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Fiber Number

Counts

proto1_S+

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Comparison of Single, Doubled-ended Splices

Spliced Fiber Testsproto1 & 2 single splice; proto3 & 4 double splice

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proto1proto2proto3proto4

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Detector Assembly

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Detector Assembly (cont.)

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Detector Assembly (cont.)

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Detector Assembly (cont.)

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Gluing of Clear Fiber to Cookie

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Diamond Finishing of Fiber Cookie

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Detector Ready to Close Up

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Cookie – PMT Alignment

Hammamatsu 64 channel MAPMT

Need to center each 1.2 mm readout fiber on a 2 x 2 mm pixel

Fiber cookie aligned in mating piece MAPMT optically aligned in jacket

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LED Calibration

Uses “flat optical panels” to produce a fairly uniform ribbon of LED lightGreen Nichia LEDsEach panel covers 8 scintillator stripsEach panel monitored by pin diode

00.20.40.60.8

11.21.41.61.8

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Results of light tests for 40 panels

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LED Calibration – Flat Panel Location

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Outreach

Much of the work done this summer under the Notre Dame QuarkNet programTalented, enthusiastic workforceNice connection with the cosmic ray “grid” programExcellent recruiting tool for future young physicists

The Team

Leroy Castle, Rich Eberly – HS teachers

Pat Kosciuk, Stan Strycker, Matt Weis – HS students

Mike McKenna - technician

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Summary and Future OutlookTwo single-sided muon detectors are complete and under test at Fermilab (see talk of R. Abrams)Two double-sided detectors nearly complete, ready for deliver within a couple of weeksFabrication techniques well understood, some improvements on original design already in placeFuture plans:

– Fabricate another 4 quarter-size detectors for beam test– Tool up for fabrication of a full-size detector– Respond to ongoing cosmic ray measurements at Fermilab– Explore new, better materials and alternative photodetectors