T2K Secondary Beamline – Status of RAL Contributions Chris Densham, Mike Fitton, Vishal Francis, Matt Rooney, Mike Woodward, Martin Baldwin, Dave Wark

Chris Densham UKNF Oxford 16 Sept 2008 Is T2K Target work relevant for a Neutrino Factory? Ken Long said (yesterday) of the UK Neutrino Factory effort: ”[we] need to exploit…partnership with T2K to enhance targetry work “ So – here is what I did in Japan (instead of) summer holidays…

Chris Densham UKNF Oxford 16 Sept 2008 T2K Secondary Beam Line DV TS BD Hadron Absorber (Beam Dump) graphite core in helium vessel Target station (TS) Target & horns in helium vessel Helium vessel and iron shields cooled by water Decay Volume (DV) 94m long helium vessel cooled by water 6m thick concrete shield ‘280 m’ neutrino detector 50 GeV PS ring Primary beam line Fast extraction Kamioka

Chris Densham UKNF Oxford 16 Sept 2008 UK/RAL responsibilities on T2K Beamline Beam window Baffle Target Target support & remote handling 0.75 MW operation “ Beam dump3-4 MW operation

Chris Densham UKNF Oxford 16 Sept Beam Aluminum cast cooling modules Graphite Blocks 4,690 Beam Dump / Hadron Absorber Displacement (max) = 8.5 mm

Chris Densham UKNF Oxford 16 Sept Hadron Absorber Module All 14 modules assembled Frame production now on progress Overall assembly will be in Sep. Installation will be in Oct. Jan.24’08 Apr.11’08

Chris Densham UKNF Oxford 16 Sept 2008 Target Station

Chris Densham UKNF Oxford 16 Sept 2008 T2K Target area Inner iron shields Inner concrete shields Support structure = Helium vessel (being constructed by Mitsui Ship. Co.) BaffleTarget and 1st horns 2nd horns 3rd horns Beam window

Chris Densham UKNF Oxford 16 Sept 2008 Proton Beam Window + pillow seals

Chris Densham UKNF Oxford 16 Sept 2008 Installation check in TS using dummy window August 08 (Actual window installation October 08)

Chris Densham UKNF Oxford 16 Sept 2008 Baffle / Collimator – to be installed Oct 08

Chris Densham UKNF Oxford 16 Sept 2008 T2K Target basic requirements Phase I Beam power: 0.75 MW at GeV –Graphite rod, 900 mm long = 2 interaction lengths –NB Only 3% of Beam Power is dissipated in target as heat c.20 kW –Start-up date: 1 st April 2009 Phase II (SuperBeam) power: 3-4 MW –A future aspiration (still < 100 kW deposited in target) –The only components currently designed for 3-4 MW operation are the hadron absorber (beam dump) and decay volume

Chris Densham UKNF Oxford 16 Sept 2008 Graphite to titanium diffusion bond Graphite-to-graphite bond Flow turns 180° at downstream window Inlet manifold Outlet manifold Upstream Window Target Design: Helium cooling path

Chris Densham UKNF Oxford 16 Sept 2008 Steady state target temperature 30 GeV, Hz, 750 kW beam Radiation damaged graphite assumed (thermal conductivity 20 [W/m.K] at 1000K- approx 4 times lower than new graphite) Maximum temperature = 736˚C

Chris Densham UKNF Oxford 16 Sept 2008 Pressures (gauge) Pressure drop = bar Helium cooling velocity streamlines Maximum velocity = 398 m/s

Chris Densham UKNF Oxford 16 Sept 2008 Target Integration with 1 st Magnetic Horn – 2 weeks ago!

Chris Densham UKNF Oxford 16 Sept 2008 Target installed within 1 st magnetic horn

Chris Densham UKNF Oxford 16 Sept 2008

Pulsed beam induced thermal stress waves in target graphite Max. Von Mises Stress = 7 MPa - cf graphite strength ~37 MPa – should be OK 8 bunches/spill Bunch length: 58ns (Full width) Bunch spacing: ~600(300) ns Rep. rate: 0.47 Hz Spill width ~5  s

Chris Densham UKNF Oxford 16 Sept 2008 IG 43 graphite 200 MeV proton fluence ~10^21 p/cm2 c. 1 year operation in T2K Radiation Damage in IG43 Graphite - data from Nick Simos, BNL

Chris Densham UKNF Oxford 16 Sept 2008 Target exchange system – under construction

Chris Densham UKNF Oxford 16 Sept 2008

Options for Neutrino Superbeams Static target difficult beyond 1 MW beam power – problems include: –Power dissipation –Thermal stress –Radiation damage –High helium flow rate, large pressure drops or high temperatures Expect to replace target increasingly often as beam power increases Is it possible to combine a moving target with a magnetic horn? New target technology may be necessary Difficult to combine liquid metal with a magnetic horn – how about flowing powder?

Prototype Powder Jet Plant Status Ottone Caretta, Tristan Davenne, Chris Densham, Peter Loveridge (Rutherford Appleton Laboratory), Richard Woods (Gericke Ltd), Tom Davies (Exeter University)

Chris Densham UKNF Oxford 16 Sept 2008 Helium Beam window beam Helium Powder hopper A flowing powder target for a Superbeam or Neutrino Factory? Magnetic horn

Chris Densham UKNF Oxford 16 Sept 2008 A flowing powder target for a Superbeam or Neutrino Factory? Flowing powder can either be an open jet (a la Merit) or contained within a pipe T2K upgrade? Suitable materials – bulk density c.f. graphite, e.g. TiO 2. Neutrino factory - tungsten powder? First experiments conducted with open jet of tungsten as most difficult case – lower density materials should be easier!

Chris Densham UKNF Oxford 16 Sept 2008 The prototype powder jet rig

Chris Densham UKNF Oxford 16 Sept 2008 =3/10ba r =~atm water supply contains powder Powder jet plant – functional layout

Chris Densham UKNF Oxford 16 Sept 2008 Powder jet plant status Risk Assessment, interlocks and controls functional specification complete October 08: wiring of interlocks and control system (DL controls group) November 08: Start running!

Chris Densham UKNF Oxford 16 Sept 2008 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 UKNF Oxford 16 Sept 2008 P 0 = 4.9 bar (abs) P 1 = 1 bar (abs) Initial bulk density = 8660 kg/m 3 = 45 % W (by volume) Jet bulk density (approx. results): Jet velocity = 7-15 m/s (100 kg in 8 seconds) ~ 5000 kg/m 3 ~ 28 % W by vol. (~ 2.5 x graphite density) Tungsten powder jet – feasibility test results