MINERvA Director Review

1. MINERvA Director Review Optical Cables and Scintillator Extrusions

2. WLS (wavelength shifting) fibers in scintillator Extruded triangular scintillator pieces 3.3cm by 1.7 cm ID - Active Target - triangular scintillators form a layer (128 triangles/layer) Light sharing between adjacent strips gives position measurement Extruded square scintillator pieces – 1.9 cm square OD - Side hadron calorimeter - 6 layers Active detector elements

3. Active Detector Elements • WLS fiber – 1.2 mm, 175 ppm, s-35 multi-clad Kuraray fiber • Same kind of fiber used CMS HCAL and CDF Preshower • Slightly less flexible than the most flexible Kuraray fiber • With attenuation length of more transparent fiber • Readout one end – mirror the other end • Longest WLS fiber length – 3.5 m • Clear fiber in optical cables takes light to PMT box • 1.2 mm s-35 Kuraray multi-clad fiber • Length about 1.2 m OD -1.4 m ID

4. Active Detector Elements • PMT Box • Brings light from clear fiber cable to multi-channel PMT • The piece which consists of the optical connector and clear fibers we call the ODU (optical decoder unit) • Cable end connects to the clear cable • Fiber end glued to PMT cookie

5. DDK Optical Connectors and Cables Clip Box Ferrule • 3 Parts Ferrule, box, and clip – uses clip instead of pins and screws • Designed by DDK (now Fujikura) in conjunction with the CDF Plug Upgrade • RMS of light transmission - 1% to 2% (connection – reconnection) • For CDF – holes for 0.83 mm, 0.9mm, and 1.0 mm fiber • Also used by FOCUS, D0, and STAR experiments • We will have DDK design new ferrule for 1.2 mm fiber – same clip and box • Optical Cables – MSU STAR method to make light tight • For light tight - RTV boot on both ends with black tube surrounding the fiber

6. Physics Requirements • We require enough light to get a position resolution of 3 mm • 8 pe/layer (photo-electron /layer) from Monte Carlo program • Per doublet for a MIP with perpendicular incidence • To determine particle type from dE/dx • 8 pe/layer from Monte Carlo program • The position and dE/dx determination should be measured directly rather than deriving them from the Monte Carlo program with the # pe • Less than a few mm of warping of scintillator in xy direction • Need to know position of scintillators • However, source scanning of layers will give this information

7. Vertical Slice Test I - # pe • #pe is measured with VST I • First triangular extrusions from Lab 5 - NICADD/FNAL Extruder • However, the hole is oval and slightly oversize • Highest light yield – fiber tight in hole • 0.5 m long and painted with TiO2 • Minerva electronics and MINOS pmt (M64) in MINOS PMT box • 1.2 mm, 3.5 m, mirrored WLS fiber – mirror at scintillator end • Length simulates the worst case • No clear 1 m cable in VST I • must multiply the result by 0.75

8. VST I • #PE – 1 Layer of triangles • 10 pe – scaling the single pe peak • 12 pe - inefficiency with /10 optical filter in connector • These agree well – average – 11 pe • Scale to 11*0.75(for cable)=8 pe/layer

9. Near Term Tests • VST II - measure position resolution directly • Jan – Feb 2005 • All parts exists • Use next generation of extrusions • Measure position resolution • Compare light between the 3 layers to show dE/dx resolution • Compare to Monte Carlo program • VST II is this decisive test • Source R & D Tests • Illuminate a separate 5 triangles array with a source • Compare light between different configuration • Compare glue to no glue, etc.

10. NICADD/FNAL Extruder • Extruded scintillator much cheaper than cast scintillator • Can create unique shapes - MINERvA triangles • FNAL group experienced with extruded scintillator – MINOS, K2K • Extruder is a collaboration between FNAL and NIU, owned by NIU • Computer controlled • Regulate mixture of polystyrene pellets and dopants • Optimize temperature and extrusion speed • The Extruder is the ideal size for MINERvA production

11. Extruder Dies • Two scintillator shapes – triangle and square • Triangular extrusion is more challenging shape • VST I – first die • Supported by FNAL, NIU, DOE-HEP through Rochester • Re-tune for making triangular extrusions for VST II • Development of new die for square scintillator • Expected to be easier • Co-extruder – coat scintillator extrusion with TiO2 • MINOS scintillator manufactored with coextruder

12. Quality Controland Production • Production run tolerances for triangular shapes • Hole production and testing

13. Fiber Procurement • Purchase 57 km of clear fiber – Rochester Task • QC – same procedure as CMS • Use cable testing box to inject light to fibers • Test 5 fibers in batch ( a fiber preform) • QC tests done by Rochester physicist and a Rochester technician • Purchase 119 km of WLS fiber – Rochester Task • QC – Lab 6 automatic fiber scanner, UV lamp and pin diodes • Not working now • Could use manual setup in Muon Lab – source and PMT • Measure 5 fibers from a batch • Mirror fibers in Lab 7 • FNAL contribution budgeted in FNAL impact statement • Lab 7 did this for CDF Plug, FOCUS, STAR ECAL, CMS HCAL, D0 • 3 steps – ice polishing sputtering and protecting the mirror

14. Connector Procurement and Polishing • DDK will design new ferrule for 1.2 mm fiber – initial QC • Measure initial connectors with Avant Optical Gauge Comparator • Coordinate measuring machine owned by Tech Support • They will measure the position and angle of holes • Measure RMS of the light of initial set of cables • Polishing at Lab 7 • Lab 7 has been polishing connectors for the last 10 years • They have experience polishing these connectors - FOCUS • DDK connectors have fiberglass which dulls the diamonds • New diamonds or relapped diamonds after 40 connector polishes • Lab 7 polishes 10 connectors at a time • FNAL Lab 8 need to build fixture to hold the connectors

15. Optical Cables and ODU Assembly • ODUs – fibers-connector part used for the PMT box • Like cable, but not made light tight • Cable construction same techniques and CDF and CMS • To make light tight – copy MSU STAR method • Put RTV boot on both ends of cable • Can prototype existing DDK connectors for 1.0 mm fiber • Fiber diameter doesn’t matter for test certain techniques • Test RTV light tight boot • Set up the production line • QC – Build quality control device • Build light injection box – like CMS calibration box • Build box to take light in cables to pin diodes • Multi-channel pico-ammeter system readout out pin diodes

16. Scintillation Extrusion Schedule • Schedule based on experience from extruder R & D • 2 dies – 2 months of testing the tuning for each die • 90 Days for production • People • 2 FNAL technicians • NIU Production Coordinator – 50% time • NIU Run Supervisor – 50% time • 9 month after June 1 – March 2005

17. Schedule • WLS Fiber • 3 months to acquire WLS fiber - • 4 months to mirrors fiber – 4 technicians • June 2005 – Dec 2005 • An Fall accelerator shutdown could effect this schedule • Optical Cables and ODUs • 3 months to acquire prototype ferrule • 1 month to test • 1 month acquire production connectors • 1 Rochester R&D Technician – Finish Nov 2005 • 7.5months – 2404 ODUs – Rochester 4 techs – Finish Jun 2005 • 12 months - 4607 Cables – 6 techs - Finish Jun 2006

18. Cable Costs • As-real eng – as realized and engineering costs estimate • Exp as-real – direct extrapolation from as realized costs • Act as-real – actual as realized costs • Sim/exp as-real – direct/similar extrapolation from as realized costs

19. Polishing and WLS Fiber Costs

20. Costs – Scintillator Extrusions