Overview of Target&Horn Activity

A.K.Ichikawa

040823 T2K collaboration meeting

1st Horn 2nd Horn 3rd Horn

Graphite Targetbeam I=320kA

Current ActivityJapanese construction group

Target design : T. Nakadaira et. al

Target FEM calculation : Y. Hayato et. al

Radiation damage study : Y. Hayato et. al

Target He cooling system : w/ Cryogenics group, IPNS, KEK

Horn conceptual design : A. K. Ichikawa et. al

Horn Cooling : H. Sato et. al

Horn expert : Y. Suzuki, Y. Yamanoi

International collaboration

US( Colorado ) (E.Zimmerman, L.Bartoszek)

Start working on design and beam MC.

RAL : possible collaboration on target and baffle starting from FEM

analysis

BNL : possible collaboration around target

50 GeV 0.75 MW beam !

cm

cm

1100o

(cf. melting point 1536o)

3.3E14 ppp w/ 5s pulse

When this beam hits an iron block,

Material heavier than iron would melt.

Thermal shock stress

(cf. 耐力 ~300 MPa)

Material heavier than Ti might be destroyed.

Cooling power and radiation shield 12GeV PS x 100

GPaTE 3

Residual dose rate

> 1000Sv/h

Stress analysis -1st horn-Most severe part will be thermal shock on the 1st horn inner-conductor.

We don’t have a satisfactory safety factor (=<25MPa) for that in case of “full”(=0.75MW

w/ 3.6sec rep. rate) beam. (Safety factor is not satisfactory but not so bad.)

But we decided that instead of a safer but less-neutrino-yielding horn, we adopt the current design at least until we get “full” beam.

30MPa

Temperature rise w/ 3.3E14 ppp

Stress analysis -2nd and 3rd horns-

900

472

2000 2500

1400

809

24MPa20MPa

Stress analysis –target-

Stress analysis for the 1 pulse T was done (and reported at the last collaboration meeting).

Full stress analysis after reaching equilibrium have not yet been done.

Thermal stress 6.8 MPa

(safety factor ~3)

One of the serious concern is whether we should divide it to pieces or not.

In case it is divided, the structure become very complicated.

Therefore, we decided to develop base design without dividing it.

Conceptual designAlmost finished.

After consideration on the stress analysis, we decided to make inner-conductors w/ 3mm-thick aluminum.

Flux generated by beam-MC w/ 3mm-thick aluminum is already distributed.

Fine tuning of the inner-conductor shape

of the 2nd and 3rd horn is on going.

(3rd horn : almost done, 2nd horn : on going.)

-> Eric’s talk.

Alignment tolerance is being studied using beam MC

-> Eric’s talk

New Flux

LOI

New flux v.s. LOI @ OAB2deg

Mainly thanks to longer DV

Horn R&D Status 1st horn1st horn prototype

Assembled into the K2K outer-conductor.

Other horn R&D status 1st horn outer conductor is being designed and will be constructed within this fiscal year.

A prototype of the 3rd horn inner conductor will be constructed within this fiscal year.

Shape of the stripline-horn coupling part is being designed.

During these designs, E.Zimmerman and L.Bartoszek is working together.

Cooling performance is investigated by H.Sato. (-> his talk)

Target R&D status

More knowledge on radiation effect -> Y. Hayato

New cooling schemes (He cooling instead of water) -> T.Nakadaira

R&D for components -> T.Nakadaira

Cost estimate　 Total 2004 2005 2006 2007 2008

Horn 2.5 0.3 0.5 0.8 0.9 　

1st horn R&D 0.2 0.1 0.1 　 　 　

2nd horn R&D 0.4 0.0 0.1 0.1 0.1 　

3rd horn R&D 0.3 0.1 0.1 0.1 　 　

horns 0.6 　 　 0.2 0.4 　

cooling system 0.1 　 　 0.0 0.1 　

support structure R&D 0.4 0.1 0.1 0.1 - 　

support structure 0.4 　 　 0.1 0.3 　

Horn Power supply 3.0 　 0.5 0.8 1.6 　

R&D 0.5 　 0.5 　 　 　

Power supply 2.5 　 　 0.8 1.6 　

Target 0.5 0.1 0.1 0.2 0.1 　

R&D 0.3 0.1 0.1 0.1 　 　

Target 0.1 　 　 　 0.1 　

cooling system 0.1 　 　 0.1 　 　

Baffle 0.4 　 0.0 0.1 　 0.2

R&D 0.1 　 0.0 0.1 　 　

Baffle 0.1 　 　 　 　 0.1

cooling system 0.0 　 　 　 　 0.0

Support structure 0.1 　 　 　 　 0.1

Unit : M$