FNAL / STFC collaborations on neutrino target R&D

1. Chris Densham High Power Targets Group Leader Technology Department STFC Rutherford Appleton Laboratory FNAL / STFC collaborations on neutrino target R&D

2. Collaborations on neutrino targets between Fermilab and STFC/RAL LBNE & NuMI (LE) target studies & prototyping 1st NOvA (ME) target for 700 kW beam 2nd NOvA target under manufacture Mu2e target design, development & materials testing under way Be window experiment proposal for HiRadMat

3. FNAL / STFC target credits / collaborations UK/STFC/RAL Otto Caretta, Tristan Davenne, Chris Densham, Mike Fitton, Peter Loveridge, Matt Rooney, Joe O’Dell, Geoff Burton, Steve Jago, Dave Turner, Richard Day, Don Clark (DL), Roger Bennett, Ali Ahmad (Sheffield Uni) Fermilab: LBNE/NuMI/NOvA: Patrick Hurh, James Hylen, Kris Anderson, Mike McGee, Cory Crowley, Bob Zwaska, Sam Childress, Vaia Papadimitriou US Mu2e: Ron Ray,Rick Coleman, Patrick Hurh, Jim Popp, Vitaly Pronskikh, Larry Bartoszek, Steve Werkema, Kurt Krempetz, Anthony Leveling, Andy Stefanik, Kevin Lynch, Igor Rakhno, Adrienne Dee Hahn, George Ginther, Michael Campbell, Horst Friedsam, Michael Gardner, Nikolai Andreev, Jeff Brandt, Vladimir Nagaslaev

4. LBNE: Combined target and horn inner conductor? A simple concept…

5. Magnetic modelling Longitudinal force in inner conductor Peter Loveridge

6. Combined effects of: 1 ms 300 kA current pulse + 2.3 MW 120 GeV beam pulseTarget diameter dominated by Lorentz forces->combined target/horn inner conductor not recommended Beam effect Horn current pulse effect

7. Otto Caretta

8. Pressurised helium cooled concept (2 MW) Mid-plane temperatures Heat transfer coefficient Otto Caretta & Tristan Davenne

9. LBNE target study: preliminary conclusions for 2.3 MW • Combined target/horn inner conductor • Not recommended as dimensions dominated by horn current pulse Lorentz forces rather than pion production • Candidate beryllium target technologies for further study: • Pressurised helium cooled separate spheres (recommended) • Water cooled longitudinally segmented (possible – a higher power version of the NuMI (LE) target)

10. NuMI (LE) target studies, re-design & prototyping How joint ended Problems of stress waves in existing IHEP stainless steel water pipes causing NuMI target failures How joint started out Otto Caretta / Peter Loveridge /Tristan Davenne Complex & delicate upstream region causing joint failures • Proposed solution: Titanium alloy pipe • lower ∆T • lower stiffness • higher strength • CTE similar to graphite

11. NuMI target re-design & prototyping • Good potential candidate for LBNE at 700 kW Graphite to titanium braze prototype Minimum & simple joints within target container Single piece titanium tube bending Mike Fitton/Joe O’Dell/Geoff Burton

12. NOVA (ME) targets MET-01 Manufactured, delivered and installed MET-03 Currently in assembly at RAL Mike Fitton

13. NOVA tests and analysis Measurement of heat transfer in target fins using thermal imaging camera identified thermal issue with cooling of budal monitor fins. Redesign of bracket more than halves the operating temperature rise. 310°C 152°C Simulation of natural convection and radiation inside target vessel. Used to estimate target fin operating temperatures and emissivity requirements of outer vessel. Mike Fitton + Tristan Davenne

14. NOVA welding development High quality welds (NAS 1514 Class II or better) in 6061 aluminium proved very difficult to produce consistently. Some welds were completely removed by marching pipe stubs from solid By visual inspection welds look very good. Radiography reveals significant porosity Latest socket weldNo porosity visible on radiography Parameters explored to optimise weld: Cleaning (including etching) Filler wire selection Pre-heating AC current/balanceGas (Helium/Argon Blend) Mike Fitton + Joe O’Dell

15. R. Ray - Director's CD-1 Review Mu2e Project • Production Solenoid • Production target • Graded field • Detector Solenoid • Muon stopping target • Tracker • Calorimeter • Warm bore evacuated to 10-4 Torr • Delivers ~ 0.0016 stopped m- per incident proton • 1010 Hz of stopped muons 4.6 T 2.5 T Cosmic Ray Veto not shown 2 T • Transport Solenoid • Collimation system selects muon charge and momentum range • Pbar window in middle of central collimator Production Solenoid 1 T Detector Solenoid Proton Beam Transport Solenoid 1 T Production Target Calorimeter Tracker

16. Mu2e Phase 1 (CD-0) study for 25 kW: water cooled gold Water cooling streamlines

17. Mu2e Phase 1: Outline target handling proposal (now taken forward by Fermilab) Joe O’Dell

18. Phase 2 (CD-1) study for 8 kW: Radiation Cooled Tungsten Wire tensioning springs Hub Interface Tungsten Target Tantalum wires Titanium mounting ring Bayonet pins

19. Mu2e target lifetime evaluation • The target will be subject to a stress cycle at elevated temperature • The target lifetime will be limited by: • Fatigue • Creep Question: how to reproduce a similar time varying stress and temperature using a pulsed power supply instead of a beam? Peter Loveridge Mu2e Target Operating Conditions

20. Proposed resistive heating test • Resistive (Joule) heating from an electric current pulse to preferentially heat the centre of a disk • Peter Loveridge to cover in next session Steady-State Von-Mises Stress Field D.C. Current Distribution Steady-State Temperature Tension Qrad ~ 200W 160A D.C - equivalent heating to 1.6kA 1msec pulses @20 Hz Compression Volumetric Joule heating (J2ρ) mostly occurs over this length Peter Loveridge

21. ‘iPASI’: Collaboration between Fermilab and PASI-UK programs • Tungsten test program for Mu2e is complementary to previous ‘little wire’ stress-wave fatigue program led by Roger Bennett • Contribution by PASI-UK in terms of both equipment and manpower • Induction heater system to heat tungsten for testing of Mu2e or ISIS targets • Contribution by PASI-UK • Be window tests at HiRadMat – extend existing collaboration with CERN