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NO A Target Part I: Status Part II: Alternative Target Material

NO A Target Part I: Status Part II: Alternative Target Material. Mike Martens NOvA Collaboration Meeting January 21, 2011. Target Major Components. Carrier. Baffle. Target Canister. Downstream Be Window (not shown). Medium Energy Target. Target Canister. Graphite Fins.

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NO A Target Part I: Status Part II: Alternative Target Material

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  1. NOA TargetPart I: Status Part II: Alternative Target Material Mike Martens NOvA Collaboration Meeting January 21, 2011

  2. Target Major Components Carrier Baffle Target Canister Downstream Be Window (not shown) Mike Martens, NOvA Target

  3. Medium Energy Target Target Canister Graphite Fins Budal Monitors (for Alignment) Water Cooled Clamping Plates Be Window (not shown) IHEP Design Mike Martens, NOvA Target

  4. Carrier • Carrier design and analysis is complete. • Carrier drawings are complete. • All parts are being fabricated with 15% completed. • Expected to complete carrier prototyping by Feb 15, 2011. Mike Martens, NOvA Target

  5. IHEP Baffle Temperature Analysis • Peak temperature is 180 C • Indium melts at 156.4 C • Still OK, • 3% loss is conservative • Peak Temp is 120 C at 2% loss • Baffle temperature is monitored • Exploring GRAFOIL as an alternative to Indium. Temperature Distribution along Baffle 3% of 800 kW beam loss, 40 W/m2/K for convention coefficient, 18 pin radiators Baffles Under Construction at IHEP. Three to be delivered by February 2011. Mike Martens, NOvA Target

  6. NOA Target Window • IPPE (through IHEP) has a prototype of the downstream target window. • First prototype used the method of diffusion welding of beryllium membrane with aluminum cup. • The prototype has passed a helium leak test. • The next prototype should be manufactured by the end of December using the same method with some variation of the welding conditions. • Three complete windows to be delivered from IHEP by July 2011. • Quote (about 1 year ago) from Brush-Wellman • Cost about $11.2K/per window • Delivery time of 10 weeks. Mike Martens, NOvA Target

  7. NOA Target Status (IHEP) • Delivered Complete (Draft) Drawing Set • Reviewed by Fermilab Engineers • A few changes suggested. • Temperature analysis of downstream support is outstanding issue. • Deliver Final Drawing Set in next few weeks. • Awaiting feedback from IHEP on target schedule • Fermilab has asked IHEP to build two additional targets for MINOS. • IHEP has doubts about completing 1st target by September 2011. • Schedule will be clearer by the end of January. • IHEP planning to build 2nd and 3rd (spare) targets as well. Mike Martens, NOvA Target

  8. Target Status Summary Baseline plan: Complete (graphite)Target Assembly by September 2011 Mike Martens, NOvA Target

  9. Additional Target from Science and Technology Facilities Council (STFC)Rutherford Appleton Laboratory (RAL) • Good to have two vendors for NOvA target. • Reduces risk of delay for completing NOvA target. • Have a backup vendor for spares production. • May need two vendors to keep up with spares production. • Will get STFC/RAL to build a target also. • Build from the IHEP drawings. • They have experience with target work. • Have worked with them in the past (on LBNE and MINOS Target) • Can build target (without downstream window) by September 2011. • Preliminary cost estimate is $xxx without window. • Pat Hurh is putting an Accord together. Thanks to Pat Hurh for initiating and pursuing this collaboration Mike Martens, NOvA Target

  10. Alternative Target Material? • MINOS target with ZXF-5Q Poco Graphite • Reduction in neutrino yield of ~2% per 11012 POT exposure. • nufact09.iit.edu/plenary/plenary_hylen-superbeamhowto.ppt • Default NOvA plan is to replace target every ~6 months • Replacement takes ~ 2weeks. (May be done during shutdowns) • Frequency may depend on experiment systematics • Designing NOvA target so individual fins could be replaced with alternative materials (IG-430, R7650, 2020, Beryllium) • Won’t know more about material for several years • Limited information on radiation damage from 120 GeV proton. • BLIP test of alternative material. Irradiated samples are being studied now. • Autopsy NT-02 in Fall 2010 when C0 Remote Handling Facility is ready (NT-02 is being saved as a “desperation spare”.) NOvA Target/Baffle/Carrier

  11. NuMI target experience( ZXF-5Q amorphous graphite ) Gradual decrease in neutrino rate attributed to target radiation damage Decrease as expected when decay pipe changed from vacuum to helium fill No change when horn 1 was replaced No change when horn 2 was replaced Each point in energy bin represents ~ 1 month running, time from 9/2006

  12. Three Options? Mike Martens, NOvA Target

  13. MARS calculation • Energy deposition in Be and Graphite are about the same. • For power density, the beam intensity was set at 4.9×1013 protons (120 GeV) per 1.33 seconds. The density of graphite was set to 1.81 g cm-3 and for Be 1.84 g cm-3. The beam was distributed transversely as a Gaussian with σx,y = 0.13 cm. The shape of the Be segments is flared transverse to the beam below the beam axis. The Be segment x-y section is shown in Fig. 1. Mike Martens, NOvA Target

  14. Properties of materials Beryllium (Be) Carbon (amorphous) (C ) Mike Martens, NOvA Target

  15. Preliminary radiation heat transfer modelFrom STFC/RAL 180W heat load Assumptions Thermal conductivity Graphite = 50W/mK Beryllium = 180W/mK Heat load 180W applied to top surface of both fins Bottom surface of both fins and surface of cooling tube set at 300K Emissivity 0.5 for all surfaces Beryllium Graphite 300K heat sink Mike Martens, NOvA Target

  16. Graphite max temperature = 1180KBeryllium max temperature = 650KThis difference is due to thermal conductivity assumption. Model needs the addition of temperature dependant thermal conductivity for both materials Graphite Contours of radiative heat flux Positive value = emitting heat Negative value = absorbing heat Beryllium

  17. Cost of Be fins • Two quotes: • $800/fin with 10-12 week delivery • $2100/fin with 18 week delivery Mike Martens, NOvA Target

  18. Be Target Design • Before going with a Be target I would want a structural analysis looking at dynamic stresses in the actual fin geometry. We have reports from RAL on 700 kW LBNE beam on Beryllium (looks fine), but that is a quite different geometry. • We have RAL studies on Be, but in rod geometry rather than fin. From previous studies, the thought was that to keep Be below the yield stress one would need an increased spot size and thus increased target size and thus some decrease in neutrino yield. The idea behind the beryllium fin was that it might be OK to surpass the yield strength on the first pulse, and the material would then be "pre-stressed“ such that subsequent pulses are OK. Or maybe we don't know how to calculate the actual stress in the Beryllium for the short beam pulses. There are some operational indications that target materials can work beyond the yield point. Putting in a couple Be fins seemed a cheap way to test this with pretty negligible impact on NOVA. Mike Martens, NOvA Target

  19. Backup Slides Mike Martens, NOvA Target

  20. Sample Irradiation at BLIP Beam in at 181 MeV, must reach isotope box at 112.65 MeV (changed from proposal) Carbon-carbon composite NuMI target graphite Japanese graphite Another graphite, higher thermal shock metric NuMI baffle graphite Highest therm. shock metric But may be: ½ hBN ½ Be ? ½ hBN ½ graphite ? IG-430 ?

  21. Summary of Upgrades (Compared to NuMI for MINOS) Mike Martens, NOvA Target

  22. Target Concerns I • Mechanical Stress • Graphite Material, Fin Design, Beam Spot Size • Safety Factor is 1.7 • Target Temperatures • Water Cooling and Thermal Radiation • Peak Steady State Temperature is 870 C • Graphite Oxidation • Graphite oxidation rate increases above 450 C • Fill Canister with Helium • Target Material Lifetime • Based on Experience with MINOS Target • Change out targets ~6 months • Test with several beryllium fins? Max Temp 876 °C Mike Martens, NOvA Target

  23. Target Concerns II • Beryllium Windows Vacuum and Thermal Stress • Thin Windows, Beam Spot Size • Complete ANSYS analysis • Alignment • Beam Based Alignment Techniques • Budal Monitors and Baffle Temperature • Increase Fin Width to 7.4 mm to provide margin. • Target Carrier and Support • New Carrier Design • Support is Simplified (No ME target motion) • Mis-steered Beam • Baffle Protects Horns. • Target can survive off-axis beam pulse. Mike Martens, NOvA Target

  24. Target Next Steps • Start with IHEP initial design • List of 36 questions/changes submitted to IHEP. • Awaiting feedback from IHEP on cost and schedule • Expect answer from IHEP early August. • Eight 1.25 mm x 135 mm diameter beryllium foils have been delivered to Fermilab • Enter into Accord (I) with IHEP for • Final Target Design • Updated Drawing Package • Prototype downstream window • Build three downstream windows. • Machine graphite fins? • Enter into Accord (II) with IHEP for • Production of three complete target assemblies Mike Martens, NOvA Target

  25. Target Next Steps • Start with IHEP initial design • List of 36 questions/changes submitted to IHEP. • Awaiting feedback from IHEP on cost and schedule • Expect answer from IHEP early August. • Eight 1.25 mm x 135 mm diameter beryllium foils have been delivered to Fermilab • Enter into Accord (I) with IHEP for • Final Target Design • Updated Drawing Package • Prototype downstream window • Build three downstream windows. • Machine graphite fins? • Enter into Accord (II) with IHEP for • Production of three complete target assemblies • Tight Schedule! • Limited IHEP resources. • Target is now critical path. • How to mitigate risk? • See next slide. Mike Martens, NOvA Target

  26. Target Schedule • Push for 1st complete target delivered Sept 2011. • IHEP manpower may be limiting factor. • Started construction of baffles already • Reduces manpower requirements in the future • Start prototype of downstream window • Fermilab just received Be foils • Start machining of graphite fins before target design is completed. • Use NOvA contingency funds as incentive for IHEP • Stagger production of targets • 1st target needed September 2011 • 2nd target needed at before start of operations in 2012 • Install target later in the shutdown? • Don’t like since crew will be busy in shutdown Mike Martens, NOvA Target

  27. IHEP Accord Update (8/31/10) • Draft Accord with IHEP • Finish the design of the NOvA-style target and provide Fermilab a complete drawing package. • Complete Jan 1, 2011 • Construct a prototype of the downstream endwall with beryllium window for the NOvA-style target. • Complete March 1, 2011 • Construct three downstream endwalls with beryllium window for the NOvA-style target. • Complete June 1, 2011 • Received word from IHEP today (8/31/10) • Schedule looks OK to IHEP • Rough estimate of cost is $85k. • Accord can be signed in September • Next Accord is for production of three targets. Mike Martens, NOvA Target

  28. New Target Carrier Design Hanger Old Design Hanger Baffle Baffle Target Target Horn 1 Horn 1 Carrier Hanger Target Canister • Medium Energy Target is located outside of Horn 1. • ME target is fixed wrt carrier. • No longitudinal motion. • Use existing hanger design. Carrier Baffle Mike Martens, NOvA Target

  29. New Target Carrier Design Lifting Fixture Hanger Target Canister Baffle Tooling Ball Water Cooling Mike Martens, NOvA Target

  30. Carrier Mike Martens, NOvA Target

  31. Carrier with Target and Baffle Mike Martens, NOvA Target

  32. Carrier with Hangers Mike Martens, NOvA Target

  33. Thermal Analysis and Strain Max Temp is 45 C Max deflection from beam heating is 0.03 mm. Alignment budget is 0.5 mm Mike Martens, NOvA Target

  34. Carrier Plans • Final Design Review Complete last week • Design reviewed favorably, only minor changes • Build Prototype Carrier here at Fermilab • Relatively simple to build, but many parts. • Finish by Jan 2011 • Final Carrier Drawing Package • Finished by Feb 2011 • Go out for bid • Construct Target Carriers (2 or 3) • Delivered by Aug 2011 Mike Martens, NOvA Target

  35. NOA Configuration Horn Power Supply Stripline Morgue Primary Beamline Work Cell (above shielding) Target & Baffle Horn 1 Horn 2 Low Energy  Configuration Horn 2 Med. Energy  Configuration Target Pile Air Cooling System (above shielding) †“Target and Horn positions for NOvA”, NOVA Document 3453 Mike Martens, NOvA Target

  36. Summary of Upgrades (Compared to NuMI for MINOS) Mike Martens, NOvA Target

  37. Baffle Indium Foil Graphite MINOS design with modifications • Baffle aperture: 11  13 mm dia • Beam size: 1.1 mm  1.3 mm rms • Add additional cooling fins • Increase in beam power • Explore alternative to indium foil • Improve margin on temperature limits Al Tube Cooling Fins Mike Martens, NOvA Target

  38. IHEP Baffle Temperature Analysis • Peak temperature is 180 C • Indium melts at 156.4 C • Still OK, • 3% loss is conservative • Peak Temp is 120 C at 2% loss • Baffle temperature is monitored • Exploring alternative to Indium (Silver?) Temperature Distribution along Baffle 3% of 800 kW beam loss, 40 W/m2/K for convention coefficient, 18 pin radiators Baffles Under Construction at IHEP. Three to be delivered by February 2011. Mike Martens, NOvA Target

  39. Target/Baffle/Carrier Target Canister Carrier Baffle Mike Martens, NOvA Target

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