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
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