Slides WEPM2X01

High Power Target Instrumentation at
J-PARC for
Neutron and Muon Sources
Shin-ichiro Meigo1), Motoki Ooi1), Kiyomi Ikezaki1),
Tomoyuki Kawasaki1), Hidetaka Kinoshita1),
Atsushi Akutssu1), Masaaki Nishikawa1),
Shinpei Fukuta1) and Hiroshi Fujimori2)
1) JAEA/J-PARC, 2) KEK/J-PARC
Outline
Introduction
Present mercury target status
R&D of beam instruments for MLF



Beam monitor
Beam flattening system
2D profile monitor
Future plans at J-PARC


Facility for R&D of ADS (TEF)
2nd target station for MLF
Materials & Life Science
Facility (MLF)
Hadron Experiment
Facility
30GeV Synchrotron
MR (0.75MW)
Bird’s eye
photo
Neutrino Exp. Facility
(294km to Super KAMIOKANDE)
3GeV Synchrotron
RCS (25Hz,1MW)
Transmutation
Facility (TEF)
(Phase II）
Linac
400MeV(50mA)
JFY2007 Beam
JFY2008 Beam
JFY2009 Beam
Neutron beam lines (23)
J-PARC = Japan Proton Accelerator Research Complex
JRR-3M
800m to MLF
3
Beam transport to MLF
600ns
FWHM ~150ns
Ep:
3GeV
Power: 1MW
Rep.: 25Hz
Length of BT: 314m
Partial of 25 Hz beam goes to MR
FX: 2.48 s, SX: 5.5 s
3-GeV
RCS
Neutrino line
road to
coast
600ns
Material and Life
Science Experimental
Facility (MLF)
MUSE
Muon
target
JSNS
Neutron
target
Targets placed at MLF
Muon target



Neutron target
Carbon graphite (IG430)
8% beam lost(80 kW loss)
Highest intensity in the world


Mercury
Highest pulse intensity in the world
Mercury target trolley
Rotating target
Thick. 2cm
Diam. 30 cm
Width 34cm Length 2m
muon target
collimators
proton beam
window
Light Water
neutron
target
Safety shroud
Double wall
structure
遮蔽（コンクリート）
遮蔽（鉄）
Muon Target
314000
アウター
ライナー
遮蔽（鉄）
B.W
陽子ビーム窓
メンテナンス用
ポート
水素輸送管
ヘリウムベッセル
遮蔽
（重ｺﾝｸﾘｰﾄ）
遮蔽（鉄）
水素減速材
neutron target
陽子ビーム
QNQ2
LQ30120
NM tunnel
QM6
Q26100MIC
QN4
Q26100MIC
X23
Y23
S2650 S2650 M23
MIC
MIC
M23
Y23
X23
S2650 S2650
proton
反射体 beam window
1600
陽子ビーム窓
QM5
QM4
QM3
QM1
QM2
Q26100MIC
Q26100MIC Q26100MIC
Q26100MIC Q26100MIC
QM1
QM2
QN3
X22
Y22
QN1
QN2
M22
Q26100MIC Q26100MIC
Q26100MIC
S2650
S2650
Q26100MIC Q26100MIC
muon target collimators
MIC
MIC M22
Y22
X22
S2650 S2650
水銀ターゲット
ベッセル内
遮蔽体
ターゲット台車
ベッセルサポート
シリンダー
ベースプレート
Proton
Hg
Present status of the mercury
target
Efforts to mitigate cavitation damage
with gas micro-bubbles
Mercury target vessel
Vibration measurement with a
LaserLaser
Doppler
Doppler Vibrometer(LDV)
Mirror
ーが数週間で破損する可能性有
Beam window (2.5 mm-t)
Most vulnerable to cavitation damage He-gas micro-bubbles
injecting into Hg target
Bubbling
distribution
Swirl type bubbler
Cavitation bubble
Bubble inflates
by the mercury
Abrupt heating negative
pressure.
of mercury
Wall
Thermal
expansion
Pressure wave
Cavitation
bubble shrinks
rapidly.
Wall
Micro-jet
Shrink energy
concentrates to
one point
Velocity amplitude (m/s)
Mercury
Time (ms)
7
Operational history of JSNS
1 MW test
593 kW
〜560 kW
532 kW
500 kW
Accident at
Hadron Facility
300 kW
400 kW
300 kW
Earthquake
Hg-target
replacement
as of September 30. 2015
Hg-target
replacement
～1 month interruption
due to the fire in MLF
Interruption due to a
trouble of Hg-target 8
Water leak events at mercury target
 In April 2015, water leak of mercury target was found during 500 kW beam
operation. Coolant water in target shroud soaked out through the defect
of the welding.
 On Nov 2015, similar event happened. Water leaked into inner shroud so
that we can not find the leaked point (possibly mirror).
 Welding of water channel might be cause of the issue. Since no robust
target and no enough space for storage remains, operational beam power
is decided as 200-kW.
Vertical cross section of the target vessel
Bolts
Mercury target
Outer shroud wall
Coolant water
Inner shroud wall
Helium gas
Mercury vessel
Mercury
Bolt
Water drop
TIG welding
Seal welding
Outer shroud wall
Water
Inner shroud wall
Helium
Mercury vessel
Diffusion bonded surface
R&D for high power beam
instruments
Beam diagnostics for profile and halo

Profile monitor and halo monitor (online monitor)



Multi Wire Profile Monitors (MWPMs) : SiC wires (15 sets)
Stationary MWPM at proton beam window (PBW), separation between
vacuum and helium, placed at 1.8 m upstream of the mercury target
2D profile： Image of residual dose read out by imaging plate (IP)
IP attached to target by remote handling after beam irradiation
MWPM
Hot cell
IP
Halo monitor
・SEC
・ TC
Target
TC
MWPM
Monitors at PBW
Imaging Plate(IP)
Beam profile at mercury target
MWPM at PBW
2-D measurement by IP
0.1 MW (2009 Dec)
0.2 MW (2010 Dec)
200
1st IP
Fit result
Peak 1.35mm
Sigma 23.8mm
100
0
-100
-50
0
50
100
Only 6 days cooling after
irradiation of 0.2 MW
beam, the image was
obtained.
⇒ Possible for 1MW with
certain cooling time
Horizontal (mm)
Profile result by the IP
• Fitted by two Gaussian
Convolution primary protons
and secondary particles
Result by MWPM
- Fit by Gaussian
• Width and position for each pulse
obtained
• Good agreement width result by IP
Proton beam at the target
Beam operational status
 Study with 1 MW beam
 User operation with 0.5MW
Cavitation damage is critical for
high power beam with short pulse
 Proportional to 4th power of the
peak current density at target
 Useless beam scanning to
mitigate damage
 More serious than SNS due to
high energy per pulse (JSNS 40
kJ/shot)
Although helium bubble injection
mitigates the damage, peak
reduction is essential.
Required development of beam
flattening system
5 cm
Damage at
JSNS target
Pin holes at
target of SNS
by R. Bernie
600ns
Here
FWHM ~150ns
Target vessel
Beam flattening system
Phase space
Intensity
Real space
(Horizontal)
Divergence
Principle: Beam edge folded by non-linear optics
Linear
Octupole magnet: 800 T/m3
Non-linear
Position
OCT1
OCT2
1m
Horizontal plan
Position
Beam tuning tool with SAD code
T=R-1M
Fit by observed width and extrapolate to target
Fit region
Extrapolate
Muon
target
oct1,2
Fitted parameter
OCT tuning
PBW
Beam profile can be estimated by tracking
Obtained beam profile
OCT 698A
Intensity (Arb unit)
0
2000
Vertical
1000
0
-100
0
Position (mm)
•
•
•
100
Horizontal
1000
0
2000
Vertical
1000
0
-100
0
Position (mm)
100
2000
Intensity (Arb unit)
1000
Intensity (Arb unit)
Dot: Exp.
Line: Calc.
2000
Intensity (Arb unit)
Intensity (Arb unit)
Horizontal
Horizontal
1000
0
2000
Intensity (Arb unit)
OCT 0A
2000
OCT 698A
with muon target
Vertical
1000
0
-100
0
Position (mm)
Flat beam was obtained and lower intensity of halo was observed
Good agreement of calculation even for with muon target
Peak smaller by 14 % and 20 % at horizontal and vertical. Overall
30~40 % reduced.
100
Beam profile at neutron target (calculation)
OCT 0A
OCT 400A
•
Ideal shape obtained
OCT 698A
OCT 698A w/ muon target
Beam loss status
Beam loss was quantitatively observed by mean of
activation obtained by dosimeter for 500 kW.
直線部C
Dose at 30 cm
Estimated beam loss
muon target
collimators
proton beam
window
neutron
target
遮蔽（コンクリート）
命実験施設
遮蔽（鉄）
Muon Target
M1
0.1 mSv/h
0.1 W/m
0.5 Sv/h
14 W/m
M2
20 mSv/h
0.5 W/m
314000
アウター
ライナー
遮蔽（鉄）
B.W
陽子ビーム窓
メンテナンス用
ポート
水素輸送管
ヘリウムベッセル
遮蔽
（重ｺﾝｸﾘｰﾄ）
遮蔽（鉄）
水素減速材
neutron target
陽子ビーム
QNQ1
LQ30120
QNQ2
LQ30120
NM t
l
QM6
Q26100MIC
QN4
Q26100MIC
X23
Y23
S2650 S2650 M23
MIC
MIC
proton
反射体 beam window
1600
陽子ビーム窓
QM5
QM4
QM3
QM1
QM2
Q26100MIC
Q26100MIC Q26100MIC
Q26100MIC Q26100MIC
QM1
QM2
QN3
X22
Y22
QN1
QN2
M22
Q26100MIC Q26100MIC
Q26100MIC
S2650 S2650
Q26100MIC Q26100MIC
muon target collimators
水銀ターゲット
ベッセル内
遮蔽体
ターゲット台車
ベッセルサポート
シリンダー
No significant beam loss aroused due to non-linear optics.
To decrease the beam loss at hands on maintenance area
(M1) with obtaining more flat shape, star shaped duct
following Q mag with large aperture is installing at the
present.
Demonstration ~1 MW beam operation
Demonstrated 0.8 MW
(0.9 MWeq) for short
duration (70 s x 7times)
due to outgas release
from foil at RCS for
charge exchange
Radiation dose at target
station showed as
same as 0.5 MW beam
Power[ kw]
1 MW
Beam profile


Anti-correlated painting makes flat shape
30 % of peak reduction (11 J/cc/pulse)
achievable for 1MW beam operation
Beam
power
(MW)
25Hz
equiv.
power
(MWeq)
Allowable RCS
RF rep.
inject.
(Hz)
paint
Area of
paint
(p mm
mrad)
0.5
0.52 (SX)
25
Anti
150
0.8
0.86 (FX)
25
Cor
100
0.94
1.0 (FX)
0.16
Cor
100
0.8 MW
w/ OCT
Time
・ Anti
・ Cor
0.5 MW
w/o OCT
Development new profile monitor
A new profile monitor required to continuously
observe 2D profile withstanding high power beam
PBW
Camera
0 Gy
Target
•
•
•
650 °C
Fujikura Fiber
980 °C
1 MGy 2 MGy
Rad hard fiber scope (Fujikura
FIGR-20, 20000 pixels) coupled
with near-IR filter
Applicable for high temperature
target (for ADS target )
Developing luminescent type
1300 °C
Proton beam window lifetime
To predict lifetime of the PBW
with high accuracy, precious
validation of calculation code
for nuclear reaction is
necessary.
Production cross section
measurement was carried out.
Result at SINQ/PSI for 0.6GeV
Y. Dai, et al, J. Nucl Mat. 343 184 (2005)
Al(p,Be-7)
Beam dump
Window Al
(0.3mmt)
Sample changer
Obtained good accuracy
Future plans at J-PARC
2nd target station for MLF
1st target ST (TS-1): 24 Hz: 1MW
2nd target ST (TS-2) 1Hz : 42kW (Designed to accept 1 MW)
TS-1
TS-2
P
3GeV
μ
n
Rotating tungsten target
Windowless Pb-Bi target
New facility at J-PARC for R&D of ADS
50mA
LINAC beam
0.5 ms
25Hz
Dump
TEF-T
RCS
TEF-P
250kW
LINAC
To MR
RCS: 25Hz 3GeV
Synchrotron
1MW
TEF-T: Lead Bismuth (Pb-Bi) target test facility


H- beam, 25Hz, 400 MeV, 250 kW
Multi purpose use: High energy neutron beam line and ISOL
TEF-P: Subcritical assembly (Minor actinide, Am, Np)

H+ beam, 25Hz, 400 MeV, 10 W

Laser charge exchange(LCE) developing
R&D of Laser Charge Exchanger(LCE)
•
•
LCE was examined at RFQ teststand using 3MeV H- beam was
conducted last week.
Demonstrated 5 W equivalent
power of beam for TEF-P (0.4 GeV,
25 Hz, peak I=50mA) extraction.
Laser
50ns
CT
FC
Phototube
Stripping
foil
H+ H0
HB
Q switch
Nd:YAG laser (25Hz)
25
Summary
To mitigate cavitation damage on the mercury
target vessel, beam flattening system has been
developed. Peak intensity will be reduced by
~30 % of linear optics.
Present beam operation had started with power of
0.5 MW. After installation of revised mercury
target at the welding, the power will be ramped up
the beam power to 1 MW.
For R&D of ADS, TEF facility hopefully will start in
a few years.
Thank you for your attention
Be patient for development of the target and instruments