Target R

1
Target RD for the J-PARC neutrino experiment
(II)

• Yoshinari Hayato (KEK/IPNS)
• for the J-PARC target RD group

2
Temperature rise estimation (simulation input
parameters)
Target size
30mm f x 900mm L
Energy deposit
58kJ/spill
Maximum energy deposit
185.9J/g
Distribution of the energy deposit
r
z
6.5kW/m2/K
Heat transfer rate _at_ surface
Temperature _at_ surface (environment)
25oC
3
Temperature rise estimation (simulation input
parameters)
Material
IG-43 (Toyo Tanso)
density
1850kg/m3
Temperature dependent material parameters
Thermal conductivity
Specific Heat
(J/kg/K)
(W/m/K)
100
60
20
Temperature (oC)
Temperature (oC)
4
Temperature rise estimation (simulation input
parameters )
Time structure for the detailed study, two
patterns were simulated.
1
2
3
4
10
11
12
Heat Load
0
3.42
6.84
10.26
30.78
34.20
37.62
Time (sec)
8spills/bunch
averaged
598ns
5ms
58ns
5
Temperature rise estimation results (I)
distribution in the target
relative temp. from 25oC
just before the 11th spill
r
Maximum Temperature 45oC
z
just after the 11th spill
r
Maximum Temperature 236oC
z
6
Temperature rise estimation results (II)
time dependence
(oC)
250
Maximum temperature at the center
200
236oC _at_maximum
150
Maximum temperature on the surface
100
85oC _at_maximum
50
(Initial temp. 25 oC)
(sec.)
Temperature is saturated in a few spills.
(oC)
250
200
150
100
Temperature rise gradually decreased because of
the temp. dependence of Cp.
50
7
Thermal stress displacements estimation
( simulation input parameters )
Temperature
Cycle 11 and 12 of the previous analysis
Material properties
Linear Expansion Coeff. (x10-6)
Youngs modulus
(oC)
Temperature
Cycle 11
Cycle 12
(oC)
200
(MPa)
150
0.0
3.6814
10760
100
20.0
3.762063
10790
50
100.0
4.065344
10920
200.0
11080
4.48612
0
1
3
2
5
4
6
7
9
8
11
10
400.0
11410
4.926584
Time (sec)
Two types of the stress analysis (LS-DYNA)
For the radial displacements (fast components)
time step 1ms (from 0 to 205ms)
For the longitudinal displacements (slower
components)
time step 10ms (from 0 to 2050ms)
8
Thermal stress displacements estimation result
s (I) equivalent stress
Just after the 11th spill
Maximum equivalent stress
6.8MPa
(x10 MPa)
9
Thermal stress displacements results (II)
displacements (radial direction)
x10-3(mm)
6.0
5.0
4.0
3.0
2.0
1.0
(sec.)
5.00005
5.0
5.00010
5.00015
5.00020
Displacement in the radial direction
6x10-3mm
Maximum displacement
Vibration cycle
6ms
10
Thermal stress displacements results (III)
displacement (longitudinal direction)
x10-1(mm)
-1.00
-2.00
5.0005
5.0
5.0010
5.0015
5.0020
(sec.)
Displacement in the longitudinal direction
2.5x10-1mm
Maximum displacement
Vibration cycle
250ms
11
Summary future prospects (I)
FEM simulation results
Maximum temperature _at_ center
236oC
(analytical _at_ center 250oC )
Maximum temperature _at_ surface
85 oC
Maximum stress
6.8MPa
(analytical 7.5MPa)
Consistent with the analytical calculation.
radial
6x10-3mm
Maximum displacement
longitudinal
2.5x10-1mm
Vibration cycle
radial
6ms
longitudinal
250ms
12
Summary future prospects (II)
Remaining questions / problems
1 piece or split the target into smaller pieces?
Off centered tolerance has to be estimated.
(Non-uniform heating may cause the problem.)
Can we put the graphite target in the water?
Is it necessary to put the target in the
container (to avoid graphite to touch the
cooling water)?
If we split the target into smaller pieces, we
have to put the target in the container.
(To avoid the water to get in the middle of the
beam.)
container(?)
water flow
Graphite target
Schematic view of the possible target (cooling)
system
13
Summary future prospects (II)
Irradiation effects
Target may shrink by 1(a few?)
Large target (L900mm) may not be possible.
If we put the target in the container, they will
be separated.
How to hold the target (in the container)?
Plan to measure the irradiation effects on
the material properties
Very rough schedule
FY 2003 simulation studies basic cooling
tests. design the prototype (target holder,
cooling system).
FY 2004 make the prototype and test. design the
target support handling system. measure the
irradiation effects.
FY 2005 mockup tests (including supports
handling system). material determination.
14
????200????? ??????? ?????mm
A????
B????
????????????????????? (?
?????5.000125sec)???