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

2. Target Major Components Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target2 Baffle Target Canister Carrier Downstream Be Window (not shown)

3. Medium Energy Target Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target3 IHEP Design Budal Monitors (for Alignment) Water Cooled Clamping Plates Graphite Fins Target Canister Be Window (not shown)

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target4

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target5 Temperature Distribution along Baffle 3% of 800 kW beam loss, 40 W/m 2 /K for convention coefficient, 18 pin radiators Baffles Under Construction at IHEP. Three to be delivered by February 2011.

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target6

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 1 st target by September 2011. –Schedule will be clearer by the end of January. –IHEP planning to build 2 nd and 3 rd (spare) targets as well. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target7

8. Target Status Summary Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target8 Target Carrier Design and drawing set is complete. Prototype complete in Feb 2011 Baffles Three IHEP baffles to arrive at Fermilab in Feb 2011. Fermilab to retrofit with Grafoil Downstream Beryllium Window IHEP (IPPE) to build three windows. Uses diffusion bonding of Be to Al cup. 1 st prototype complete and passed helium leak test. 2 nd prototype in progress. Three production windows scheduled by July 2011. NOvA Target (IHEP) Fermilab has reviewed IHEP drawing set. Final IHEP drawing set expected in several weeks. Still waiting on cost and schedule estimate for Target. September 2011 delivery not likely. NOvA Target (STFC/RAL) STFC/RAL to build one target from IHEP drawings. Preliminary cost estimate $107k (without downstream window) Preliminary schedule is delivery by September 2011. Accord is in progress. Baseline plan: Complete (graphite)Target Assembly by September 2011

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target9 Thanks to Pat Hurh for initiating and pursuing this collaboration

10. Alternative Target Material? MINOS target with ZXF-5Q Poco Graphite –Reduction in neutrino yield of ~2% per 1  10 12 POT exposure. –nufact09.iit.edu/plenary/plenary_hylen-superbeamhowto.pptnufact09.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”.) 4/10/2010 10NOvA Target/Baffle/Carrier

11. How to build a Superbeam Jim Hylen / NUFACT09 July 21, 2009 Page 11 NuMI target experience ( ZXF-5Q amorphous graphite ) Decrease as expected when decay pipe changed from vacuum to helium fill Each point in energy bin represents ~ 1 month running, time from 9/2006 Gradual decrease in neutrino rate attributed to target radiation damage No change when horn 1 was replaced No change when horn 2 was replaced

12. Three Options? Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target12 Baseline (Graphite) Stick with graphite target. Expect ~5-10% loss in flux. Replace target every 6-12 months. Ready to go with this option; targets designed Have a graphite target available in any scenario. Graphite + 2 Be fins Substitute Be in 2 of the 48 graphite fin locations. Use this as a test of Be durability. Would need a target autopsy to determine viability of Be. Autopsy results ~2 years after running. Initial engineering results are positive. Reasonable compromise. Gain experience with Be. Relatively low risk. All Beryllium Target Build target with all Beryllium fins. More expensive per target (additional ~$60k) May last longer than graphite – so save money and downtime. Determine if Be is viable from neutrino flux in 1 week, 3 months, 6 months? Would require more engineering analysis and neutrino flux simulations. Riskier but with potential gains. Able to consider with STFC/RAL building a target. If Be target fails, then fall back to the graphite.

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 σ x,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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target13

14. Properties of materials QuantityValueUnitsValueUnits Atomic number4 Density1.85g cm -3 Minimum ionization1.595MeV g -1 cm 2 2.947MeV cm -1 Nuclear collision length55.3g cm -2 29.93cm Nuclear interaction length77.8g cm -2 42.10cm Pion collision length82.4g cm -2 44.60cm Pion interaction length109.9g cm -2 59.47cm Radiation length65.19g cm -2 35.28cm Melting point1560.K1287.C Boiling point @ 1 atm2744.K2471.C Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target14 Beryllium (Be) QuantityValueUnitsValueUnits Atomic number6 Density2.00g cm -3 Minimum ionization1.749MeV g -1 cm 2 3.497MeV cm -1 Nuclear collision length59.2g cm -2 29.60cm Nuclear interaction length85.8g cm -2 42.90cm Pion collision length86.5g cm -2 43.23cm Pion interaction length117.8g cm -2 58.89cm Radiation length42.70g cm -2 21.35cm Carbon (amorphous) (C )

15. Preliminary radiation heat transfer model From STFC/RAL Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target15 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 Graphite Berylliu m 180W heat load 300K heat sink

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

17. Cost of Be fins Two quotes: $800/fin with 10-12 week delivery $2100/fin with 18 week delivery Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target17

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target18

19. Backup Slides Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target19

20. Sample Irradiation at BLIP LBNE weekly meeting Jim Hylen March 10, 2010 Page 20 Beam in at 181 MeV, must reach isotope box at 112.65 MeV (changed from proposal) Highest therm. shock metric But may be: ½ hBN ½ Be ? ½ hBN ½ graphite ? IG-430 ? NuMI target graphite Japanese graphite Carbon-carbon composite Another graphite, higher thermal shock metric NuMI baffle graphite

21. Summary of Upgrades (Compared to NuMI for MINOS) Baffle: Minor Changes Aperture Increased from 11 mm to 13 mm diameter Alternative Clamp Material Target: New Design No Remote Longitudinal Motion Larger Target Casing Same Graphite Material, but wider target fins Carrier: New Design No Remote Longitudinal Motion Simpler Construction Horn 1: Modifications for 700 kW Thinner Outer Conductor Modified Stripline Geometry Additional Spray Cooling Horn 2 : No Change Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target21

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? Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target22 Max Temp 876 °C

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target23

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 Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target24

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 Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target25 Tight Schedule! Limited IHEP resources. Target is now critical path. How to mitigate risk? See next slide.

26. Target Schedule Push for 1 st 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 –1 st target needed September 2011 –2 nd 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 Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target26

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. Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target27

28. New Target Carrier Design Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target28 Baffle Target Hor n 1 Carrier Baffle Target Horn 1 Hanger Target Canister Baffle Carrier Hanger Medium Energy Target is located outside of Horn 1. ME target is fixed wrt carrier. No longitudinal motion. Use existing hanger design. Old Design

29. New Target Carrier Design Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target29 Hanger Target Canister Baffle Lifting Fixture Water Cooling Tooling Ball

30. Carrier Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target30

31. Carrier with Target and Baffle Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target31

32. Carrier with Hangers Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target32

33. Thermal Analysis and Strain Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target33 Max Temp is 45 C Max deflection from beam heating is 0.03 mm. Alignment budget is 0.5 mm

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 Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target34

35. NO A Configuration Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target35 Primary Beamline Horn Power Supply Target Pile Air Cooling System (above shielding) Target & Baffle Work Cell (above shielding) Horn 1Horn 2 Low Energy Configuration Stripline Horn 2 Med. Energy Configuration Morgue NuMI Design NO A † Beam Power (kW) 400700 Energy Spectrum Low Energy Medium Energy Cycle time (s) 1.871.33 Intensity (ppp) 4.0×10 13 4.9×10 13 Spot Size (mm) 1.01.3 † “Target and Horn positions for NOvA”, NOVA Document 3453

36. Summary of Upgrades (Compared to NuMI for MINOS) Baffle: Minor Changes Aperture Increased from 11 mm to 13 mm diameter Alternative Clamp Material Target: New Design No Remote Longitudinal Motion Larger Target Casing Same Graphite Material, but wider target fins Carrier: New Design No Remote Longitudinal Motion Simpler Construction Horn 1: Modifications for 700 kW Thinner Outer Conductor Modified Stripline Geometry Additional Spray Cooling Horn 2 : No Change Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target36

37. Baffle 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 Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target37 Graphite Al Tube Cooling Fins Indium Foil

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?) Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target38 Temperature Distribution along Baffle 3% of 800 kW beam loss, 40 W/m 2 /K for convention coefficient, 18 pin radiators Baffles Under Construction at IHEP. Three to be delivered by February 2011.

39. Target/Baffle/Carrier Jan 21, 2011 NOvA Collaboration Meeting Mike Martens, NOvA Target39 Target Canister Baffle Carrier