Target mainly by T. Nakadaira, Y. Hayato, A.K.Ichikawa

Target mainly by T. Nakadaira, Y. Hayato, A.K.Ichikawa

Here, I will report about the present status on target R&D.

Current main member around target

Construction group leader T. Kobayashi

Convener of target and horn system : A.K.Ichikawa

Convener of target station : Y. Yamada

Target design : T. Nakadaira et. al

Target FEM calculation : Y. Hayato et. al

Radiation damage study : Y. Hayato et. al

International collaboration

Horn, especially on 2nd horn with E.Zimmerman and L.Bartoszek

Target : start discussion with RAL

Thermal Stress

J/gK degree

Z

RTemperature rise of the target due to the radiation

w/ 1 pulse

cal. w/ MARS

2.6MJ in 5sAluminum cannot withstand.Only low-Z material such as graphite or beryllium.

Thermal stress 6.8 MPa

(safety factor ~3 against fatigue strength)

Water cooling

Water Temp. 25oCHeat transfer rate 5kW/m2K confirmed by cooling testFlow rate 20 l/min

Case(container)

Target(Graphite)

Gap

IG-110 @400oC 2dpa -> -0.5%

Effect of irradiation

@ J-PARC

0.26dpa/year

Effect of irradiation on graphite

Damage by neutron irradiation 0.25dpa@200oC 　… Change of dimension +0.14% Thermal conductivity -98%0.13dpa@300oC 　… … Change of dimension -0.01% Thermal conductivity -75%

Coaxial cooling pipe : Ti or Graphite

Time evolution of temperature(assuming specific heat at constant pressure)

780℃

660℃~430℃~620℃

380℃25℃

~80℃

Condition (example)

~600W/m2K @~1atm. flow velocity 170m/s

Prototype design of Target system

Prototype design for He cooling pipe is in progress.

Entrance of He

Exit of He

graphite Target

Graphite Cap

Inner Pipe t=2.0mm Graphite

or t=0.3mm Ti (Ti-6Al-4V)

Outer Pipe t=0.3mm Ti-6Al-4V

baffle

FVD2

Temperature rise with nominal beam

理想的なバッフル ターゲット外径

= バッフル内径 水冷の場合

配管 Al 0.8mm

Temperature rise with mis-directed beam

Baffle –other possibility-

One of the Concept of Horn support

第３ホーン形状図

Rod for position measurement

Adjusting bolt

Adjusting bolt

vertical alignment rods

frame A(fixed)

frame B(verticalmotion)

frame C(horizontal

motion)

xy-stage

by S.Koike

Another Concept of Horn support

~4m

~1m

~1.5m くらいか

支持基準

支持基準を 100mで調整できれば、~1mm は達成できる？

Other R&D items -Remote Maintenance-

Side View

Top View

Disconnect Horn and it’s support structure including strip-lines.

Is this realistic?

Residual radiation level should be checked.

Anyway, we need remotely connectable/dis-connectable cuppling

For strip-lines and water pipes.

comments

The target is a critical part of the project and the relation to the 1st horn is rather complicated.

I feel that careful discussion is necessary before the real collaboration on the target to make clear situation.

Supplement

Target Nu-TAC 以後の進展Graphite の熱応力の再評価 (S. Ueda)

比熱の温度依存性の update & bug fix

等価応力[MPa] 安全率

東洋炭素 IG-43 7.48 4.0

東海カーボン G-347 5.55 4.5

等価応力[MPa] 安全率

7.42 3.51

6.45 3.41

安全率３　は満たされている。 東洋炭素 ISO-88 についても安全率を評価

等価応力[MPa]

引張強度[MPa]

安全率

東洋炭素 ISO-88 11.24 68.6 4.27

内側配管の温度勾配 / 応力分布Al 合金 (0.8mm 厚 ),Ti 合金 (0.3mm 厚 )

~200℃

動径方向応力<10kPa

円周方向応力< ２Ｍ Pa

軸方向応力< ４Ｍ Pa

等価応力 < ３Ｍ Pa 安全率

横軸 : 0= 最内面1= 最外面

Ｈｅ冷却管のプロトタイプの設計He の流量、除熱能力を試験したい。KEKB/Belle の衝突点チェンバー冷却用の He

システムを使ったテストの検討中。 最大ゲージ圧 0.1MPa, He 流量 400 [l/min] カウンターホール

への移設可• 電源 : 200V15A• 冷却水 10-50[l/min]

冷却配管を設計中絶縁材の材質を検討中