remarkable pressure rise at pumping port in j-parc … · remarkable pressure rise at pumping port...
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REMARKABLE PRESSURE RISE AT PUMPING PORT IN J-PARC MAIN RING
Masahiko Uota #, Masayuki Shimamoto, Yoshihiro Sato, Yasuhiro Takeda, Yoichiro Hori, Yoshio Saito
KEK
1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
Abstract In J-PARC MR synchrotron with high power beam operation, the remarkable and endless pressure-rise over 10-4 Pa
or more is found when a ion-pump of the ring turns off by accident or on purpose. This high pressure exceeds the normal pressure distribution of pump series and causes the beam loss by nuclear interaction. The outgassing rate depends on the existence of external magnet field at the pumping port, the initial pressure and the operating beam power. A minus potential synchronized with the operating cycle are found at the electrode in pumping port. The formation of electron cloud is considered to the pressure rise.
J-PARC MRイオンポンプ OFF時の顕著な圧力上昇
1. J-PARC 50GeV (MR)
3.0430GeV 92×1012 (145kW )
MR1600m
MR 0.5—0.6 m3/s (IP) in-vacuum
[1,2] 2010 1 35kW
IP #111( 1 ) 5 60kW
IP 26×10-7 Pa
1.2×10-6 Pa
10-3 Pa
MPS( 1 )
IP
IP 2
2. 2011 MR IP 2
MR 1 module 15 50.8m 24 module2010 IP 1.5
/module 34mmodule
IPdispersion
3-50BT
RCS
Abort Dump
WALL
Slow
Ext
ract
ion
Neutrino Beam Line RFRF
KM
1
KM
2,3
KM
4,5
SM
1,2
SM
31~
34
0 25 50 100m
ESS2
SMS3
SMS2
SMS1
ESS1
InjK
COL1
COL2
COL3
ABS
InjSM1,2
GV
GV
GV GV
GV
GV
GV
GV
GV
GV(A)
GV2
GV(HD)
GV(N)
GV
GVGV
GV
GV
GV
GV
GV
GV
GV1
GV3
GV4
IP2
IP3IG4CG
4
RP3
@M
W
IG3CG3RP2@MWIP1IG1CG1
IG2CG2RP1 IG5IP4IG6(NC)
PLUG1
IG8CG6RP6
IG7CG5@MW
IG9
IP11
IG10
CG
7
RP7
@M
RPM
RP
CG,RPIP13
IP12
RP
IP,IG013
IP,RP,IG015
RP
RP
IG005,CG,RP
IG006
CG,RPIG004@MRPM
IP,IG008
IP,IG012
IP,IG011_1
IPIP
IPIP
IP14
IP5
IP6
IP7
IP8
IP10
IP107
IP097
IP093
IP087_1IP_SLOWEXT
IP085
IPIPIPIP
IPIP
IP
IPIP
IPIP
IP111
IP116
IP121
IP125
IP130IP135IP139
IP144
IP146
IP148
IPIPIPIPIPIPIPIPIPIP IP150_1
IP
IP159
IP165
IP169
IP174
IP179
IP183
IP188
IP193
IP197
IP202
IP207
IP211
IP216
IP102IP021
IP025 IP028
IP042
IP056
IP
IP100
IP114
IP128
IP142
IP172
IP186
IP200
IP214
IP030 IP035 IP039
IP044
IP049
IP053
IP058
IP
IP
IP
IP074
IPが粗 : 最近接IPまで34mIPが密 : 最近接IPまで15~18m
Arc A
Arc BArc C
Insertion A
Insertion C
Inse
rtio
n B
粗密
粗
密
粗
密
粗
2011/1IP入口にシールド(パンチングメタル) 密
2011/1ループアンテナ
2011/1円盤電極
AB
B
Aʼ
A
Aʼ
2: MR (2011 3 ).
10
-7
10-6
10-5
10-4
10-3
Pre
ssur
e [P
a]
16:1505/11/10
16:30 16:45 17:00 17:15 17:30 17:45 18:00
dat
60
40
20
beam
pow
er [
kW]
IG_028p IG_042p
IG_049p MRPWRv
IP039&044 off bycontroller down
Beam off byMPS(BLM)
~1e-6 Pa incontinuous operation
exponentially(or more) rise
cont. op.resume
1: OFF-IP (2010 ). ____________________________________________ # [email protected]
Proceedings of the 8th Annual Meeting of Particle Accelerator Society of Japan (August 1-3, 2011, Tsukuba, Japan)
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IPIP
2010 463kW IP
10-4 Pa
12IP
IP2010 100kW140kW
10-6 Pa3 2009 2011 3
3Ti
IP
130mm
80cm
DC
3.
3.1
1—2 IP
A
A’
B
4: IP OFF .
2010 2
IP OFF10-4Pa ON
10-4Pa 2—3IP
OFF
2010/11—2011/1 95—110kW3
OFF (B-A ) 4 2
IP
1 ( )
1 ON/OFF
A, A’
68m3—10 10-4Pa
B
10-7
10-6
10-5
10-4
10-3
Pre
ssur
e [P
a]
IP002
——
——
IP004
Injsep2(2)—
——
—InjK
ick(2)C
ollimatorA
reaD
Kick(-2010/8)
IP013
IP015
IP021
IP025
IP030
IP035
IP039
IP044
IP049
IP053
IP058
IP063
IP067
IP072
IP074
ES
S1(2)
——
——
ES
S2(2)
IP078
IP079
SM
S1(2)
——
——
SM
S2(2)
IP087
IP093
IP097
IP102
IP107
IP111(2009/12)
IP116
IP121
IP125
IP130
IP135
IP139
IP144
RF
area1R
Farea2
IP150
——
—K
M1(2)
——
——
——
KM
2(2)K
M3(2)
——
——
KM
4(2)—
——
——
——
—K
M5(2)
SM
1(2)—
——
—S
M2(2)
IP157
IP159
IP165
IP169
IP174
IP179
IP183
IP188
IP193
IP197
IP202
IP207
IP211
IP216
Main Ring 1567.5m
QD
X216
QD
X016
QD
X072
QD
X088
QD
X144
QD
X160
QD
X216
Insertion A(116.1m)
Arc A(406.4m)
Arc BInsertion B Arc C
Insertion C
FX Septum 1, 2
FX K
icke
r 1-
5
SX S
eptu
m 1
, 2
Inj.Septum 2
ESS
1, 2
RF
disp. max without IP
disp. max with IP
Collimator Area
IP028(2010/8)
IP042(2010/8)
IP056(2010/8)
IP070(2010/8)
IP100(2010/8)
IP114(2010/8)
IP128(2010/8)
IP142(2010/8)
IP172(2010/8)
IP186(2010/8)
IP200(2010/8)
IP186(2010/8)
Dat
a m
issi
ng b
y no
ise
3: .
A 34m 34m 68m,
A’ 17m 17m 68m, 2
B 34m 17m 51m,
Proceedings of the 8th Annual Meeting of Particle Accelerator Society of Japan (August 1-3, 2011, Tsukuba, Japan)
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A, A’B
• A, A’ B •
•
1–2×10-6Pa • (
)
3.2
A, A’ B(68m 51m)
1.5
A A’ 21 ( 2 IP)
( 5a)Q
A’ 1B Q Bend
( 5b) 5a QBend (
)
• dispersion
• Q
( Q 3m D.S.)
• Q Bend
5: a) missing bend Q , b) Q Bend .
bellowsbellows
bellows
outer tube
inner tube
contact point
floated Be-Cu fingers
pumping
binding ring
Ion Gauge (back)
2 Electrodes(Floated)
to OSC
Ion Pump
bellows
Ion Gauge (back)
2 Electrodes(Floated)
to OSC
6:
4. #146 RF
( )30mm
( 6) IP
RF
dispersion 2 IP144 IP14814m IP146
29m
phase 1 turn7
bunch
BPM
7: ( : , : ).
Proceedings of the 8th Annual Meeting of Particle Accelerator Society of Japan (August 1-3, 2011, Tsukuba, Japan)
- 1385 -
8: LPF & 8 shots
RC( 1k 1μF) 150Hz LPF8
1( 8)
9
LPF C(1s) decay
( )
300.5nC/μPa
120mm 10nC/μPaB-A
ON/OFF
5.
/
consistent 3
(OFF )
3
6.
7. LPF RF
[1] M. Uota, et al., “J-PARC MR
”, Proceedings of the 7th Annual Meeting of Particle Accelerator Society of Japan (August 4-6, 2010, Himeji, Japan), p721.
[2] M. Uota, et al., “VACUUM SURFACE SCRUBBING BY PROTON BEAM IN J-PARC MAIN RING”, Proceedings of IPAC’10, Kyoto, Japan, p3858.
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
Ele
ctro
de P
oten
tial [
mV
]
-2 -1 0 1 2Operation Cycle [s]
8times average 5e-7Pa +IGoff IGon, IPoff, 1.2e-6Pa IGoff, IPoff, 1.5e-6Pa IGon, IPoff, 2.1e-6Pa IGoff, IPoff, 2.6e-6Pa IGoff, IPoff, 4e-6Pa IGon, 2IPoff, 8e-6Pa NO BEAM, 2.2e-6Pa
BE
P3P2
P1
IGon, 2IPoff, 8e-6Pa
IGoff, IPoff, 4e-6Pa
IGon, IPoff, 2.1e-6Pa IGoff, IPoff, 2.6e-6Pa
IGoff, IPoff, 1.5e-6Pa
IGon, IPoff, 1.2e-6Pa
5e-7Pa +IGoff
NO BEAM, 2.2e-6Pa
2011.2.15-163.2s cycle, 136kW
next P1
next P2
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
Peak
Vol
tage
[m
V]
1086420Pressure [μPa]
NO BEAM
Peak Voltage vs Pressure
IP ONIG ON/OFF
IP OFF
9:
Proceedings of the 8th Annual Meeting of Particle Accelerator Society of Japan (August 1-3, 2011, Tsukuba, Japan)
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