T2K Secondary Beamline – Status of RAL Contributions Chris Densham, Mike Fitton, Vishal Francis,...

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…


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’ neutrinodetector

50 GeV PS ring

Primary beam lineFast extraction

Kamioka


UK/RAL responsibilities on T2K Beamline

• Beam window

• Baffle

• Target

• Target support & remote handling

0.75 MW operation

“

“

• Beam dump 3-4 MW operation


5

BeamBeam

Aluminum cast Aluminum cast cooling modulescooling modules

Graphite Blocks

4,6

90

4,6

90

Beam Dump / Hadron Absorber

Displacement (max) = 8.5 mm


6

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


Target Station


T2K Target area

Inner iron shields

Inner concrete shields

Support structure= Helium vessel(being constructed by Mitsui Ship. Co.)

Baffle Target and 1st horns2nd horns

3rd horns

Beam window


Proton Beam Window + pillow seals


Installation check in TS using dummy window August 08

(Actual window installationOctober 08)


Baffle / Collimator – to be installed Oct 08


T2K Target basic requirements

• Phase I Beam power: 0.75 MW at 30-40 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: 1st 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


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


Steady state target temperature

30 GeV, 0.4735Hz, 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


Pressures (gauge)Pressure drop = 0.792 bar

Helium cooling velocity streamlinesMaximum velocity = 398 m/s


Target Integration with 1st Magnetic Horn – 2 weeks ago!


Target installed within 1st magnetic horn



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 ~5s


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


Target exchange system – under construction




















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)


Helium

Beam window

beam

Helium

Powder hopper

A flowing powder target for a Superbeam or Neutrino Factory?

Magnetic horn


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. TiO2.

• Neutrino factory - tungsten powder? • First experiments conducted with open jet of

tungsten as most difficult case – lower density materials should be easier!


The prototype powder jet rig


=3/10bar=~atmwater supplycontains powder

1

2 34

5

7

8

6

91011

12

Powder jet plant – functional layout


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!


Tungsten powder open jet first results:

(Thanks to EPSRC Intrument Loan Pool for use of a high speed video camera)

2

cm

30 cm


P0= 4.9 bar (abs)

P1= 1 bar (abs)

Initial bulk density

= 8660 kg/m3

= 45 % W (by volume)

Jet bulk density (approx. results):Jet velocity = 7-15 m/s(100 kg in 8 seconds)

~ 5000 kg/m3

~ 28 % W by vol.

(~ 2.5 x graphite density)

Tungsten powder jet – feasibility test results

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T2K Secondary Beamline – Status of RAL Contributions Chris Densham, Mike Fitton, Vishal Francis,...

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