WP2: Targets Proposed Outline Work Programme Chris Densham

A few quotes from the EUROnu proposal: 1)The target is probably the most difficult problem for both a Superbeam and a Neutrino Factory. 2)For a Superbeam facility, the integration of the target inside the horn has to be considered from the beginning of the project. 3)The work on the [neutrino factory] target is very similar to that for the Superbeam and will be undertaken in that [i.e. this] work package. -> Therefore, target options should be considered in terms of compatibility with both a Superbeam and a Neutrino Factory.

Chris Densham Powers and power densities in a few target systems MaterialBeamPower in target kW Peak power density J/cc/pulse Pulse length SPL-SBHeavy metal? 2.2/3.5 GeV protons – 2.2x10 -3 s T2KGraphite30-50 GeV protons x10 -6 s Neutrino Factory Hg jet or tungsten GeV protons Few x10 -9 s SNS (J-SNS) Contained Liquid Hg 1 (3) GeV protons 1400(1000)10 (17)1x10 -6 s GSI/FAIRLi or Graphite Heavy ions??300005x10 -9 s

Chris Densham SPL-SB Baseline Schematic layout: Neutrino Factory Baseline Schematic layout: Both baselines use liquid mercury jet target

Chris Densham Pulsed beam interactions with mercury MERIT experiment: Beam-induced splashing of mercury jet (c.200 J/cc) - Damping of splashes due to magnetic field observed as predicted - Analysis of MERIT data required Cavitation damage in wall of Hg target container after 100 pulses of 19 J/cc proton beam (WNR facility at LANL) Contained mercuryFree mercury jet

Chris Densham Can a free mercury jet be combined with a magnetic horn? Magnetic horns are typically manufactured from aluminium alloy Mercury is commonly known to cause severe and rapid erosion of aluminum and its alloys Is it possible to protect a horn with a material compatible with liquid mercury? –If so, would the jet be open or contained? Corrosion problem is in addition to the shock wave problem Combination of a mercury jet with a magnetic horn would appear to be extremely difficult Analysis of MERIT data necessary but not sufficient

Chris Densham How about graphite targets? (pion+muon production for a neutrino factory) MARS simulations by Harold Kirk Graphite looks competitive with mercury for SPL beam energy (2-3 GeV)

Chris Densham T2K graphite target design and installation within the 1 st magnetic horn for T2K Phase 1 (750 kW beam, 30 kW deposited in target) Max. helium velocity c.400 m/s

Chris Densham Solid targets for Superbeams How high a power can a static graphite target dissipate for a Superbeam or a Neutrino Factory? –T2K phase 1 target power = 30 kW –c.f kW on target for SPL-SB! –Static graphite target appears unfeasible for SPL-SB Is it possible to combine a moving target with a magnetic horn?

Chris Densham Helium Beam window beam Helium Tungsten powder hopper A flowing powder target for a Superbeam or Neutrino Factory?

Chris Densham Tungsten powder open jet first results: (Thanks to EPSRC Intrument Loan Pool for use of a high speed video camera ) 2 cm 30 cm

Chris Densham Powder jet targets: some potential difficulties Erosion of material surfaces, e.g. nozzles, valves Activated dust on circuit walls (no worse than e.g. liquid mercury?) Activation of carrier gas circuit Achieving high material density – typically 50% material packing fraction for a powdered material

Chris Densham Outline Targets Programme 1)Contribution to interpretation of results of MERIT experiment. This will answer many technical questions regarding liquid metal jet targets 2)Study of integration of mercury jets with a magnetic horn 3)Investigate ideas and limits for static and moving solid targets 4)Continue flowing powder target studies at RAL 5)Begin studies of target integration with collection system both for Nufact (solenoid) and for SuperBeam (magnetic horn) 6)Evaluate relative merits of different target options