Lecture_B2_S_Noguchi_part_8_ILCMeasurment
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Transcript Lecture_B2_S_Noguchi_part_8_ILCMeasurment
Superconducting Cavity
Design ( RF, Mechanical, Thermal )
Material
Fabrication Techniques
Surface Treatment
Surface Inspection
Vertical Measurement
Cavity Behavior
Part-3
Diagnostics
Shuichi Noguchi, KEK
6-th ILC School, November 2011
1
Cavity Measurement
Vertical Cryostat Measurement
Q – Eacc , Rs , Pass-band
Observed Phenomena
Diagnostics
Shuichi Noguchi, KEK
6-th ILC School, November 2011
2
Preparation for Vertical Test (1)
Final EP ~20mm
Hot Bath Rinsing at 55oC
HPR for 6 hours
Shuichi Noguchi, KEK
6-th ILC School, November 2011
Assembly in Clean Room
3
Preparation for Vertical Test (2)
Baking at 120℃
for ~48 hours
Shuichi Noguchi, KEK
Mounting to
Vertical Test System
6-th ILC School, November 2011
Installation into
Vertical Cryostat
4
Surface Resistance & Q-E Curve
RS RBCS Rresidual
#1 Baseline Cavity ; 1'st Vertical Test
#1 Baseline Cavity ; 1'st Vertical Test
10
1011
-6
Qo 1.8K
Rbcs
Geometrical Factor = 277.
Rs
10-7
1.8 ~ 2.0 K
Qo
Rs
Qo 4.2K
1010
Rres = 11.5 n
Eacc, max = 19.1 MV/m
9
10-8
10
Rbcs (T)
10
Qo = 4.7 x 10 , Po = 82 W
9
4.2 K
Eacc, max = 7.8 MV/m
8
-9
0.2
0.25
0.3
0.35
0.4
0.45
1/T [1/K]
0.5
0.55
0.6
10
Qo = 4.7 x 10 , Po = 47 W
8
0
5
10
15
20
25
Eacc [MV/m]
Shuichi Noguchi, KEK
6-th ILC School, November 2011
5
Cavity RF Parameters
Eacc
RS
P0
2
1
LCavity
W
2
L
0
Ez z, r 0cos t z dz
H dS , W
m
2
G
Q0
, G m
P0
RS
2
H dV
2
2
E dV
2
H dV
2
H dS
2
E
R G
R Eacc 2
2
Rsh
LCavity
,
LCavity
P0
Q W
Q RS
2
acc
Shuichi Noguchi, KEK
6-th ILC School, November 2011
6
Cavity Measurement
0
0
Decay ; W exp
t , Band Width ; QL
2
QL
QL
Measurable
Pg , Pr , Pn
Po , , n , in , Qo , Qin , Qn
Measurable
Eacc
1
LCavity
Shuichi Noguchi, KEK
R
1
W
LCavity
Q
6-th ILC School, November 2011
R
Pn Qn
Q
7
Measurable
Pg ; Generater Power ( Pf ; Forward Power )
Pr ; Re flected Power , Pt ; Trnsmitted Power
TF ; Filling Time , f ; Re sonance Half Bandwidth
t
f0
QL
, Pt exp
2 f
QL
1
1
1
1
QL Q0 Qin
n Qt , n
Shuichi Noguchi, KEK
6-th ILC School, November 2011
8
Power Flow & RF Test Set-up
RF Amplifier
Directional
Coupler
Cavity
Circulator
P0
Pg
Pr
Phase
Detector
Pt
Monitor
RF Signal
Generator
Shuichi Noguchi, KEK
Frequency Modulation
6-th ILC School, November 2011
Monitor
Power Meter
Oscilloscope
9
Calculation
r
Pr
1 r
,
; for under couple,
Pg
1 r
P0 Pg Pr Pout , out
1 r
; for over couple
1 r
Pout
P0
in 1 out , Q0 1 in out QL
Eacc
1
LCavity
Shuichi Noguchi, KEK
R
1
W
LCavity
Q
R
Pn Qn
Q
6-th ILC School, November 2011
10
Step Pulse Response
P0 Q0
dW
Pg Pr P0
, W
dt
t
VC Vg 1 exp 2
TF
V
P0
4 Pg
2
R
1
Q0
Q
2
C
R QL2
Pg
Q Qin
t
1 exp
TF
t
1 exp
TF
2
t
t
d W Q0 d P0 4 Pg
1 exp exp
dt
dt
1
TF
TF
t
Pr 1
2
1
exp
Pg 1 1
TF
2
Shuichi Noguchi, KEK
2
6-th ILC School, November 2011
11
Step Pulse Response
Pr
Pg
１
1
2
t
In
1 1
2 Q0
Under Couple
1
1
2t
Pr
42
exp
2
Pg 1
TF
2
Over Couple
=1
０
ｔ
Pulse Head
Shuichi Noguchi, KEK
ｔ
Pulse End
6-th ILC School, November 2011
12
Q-E Curves
Q0
Ideal (Constant Q = Constant Rs, T)
Multipacting
Quench ?
Q Slope
H Q-Dieses
Q Switch
Field Emission
I ESP
2.5
Shuichi Noguchi, KEK
Global Heating
1.5
exp
ESP
6-th ILC School, November 2011
Quench
Quench
Eacc
13
Observed Phenomena
Quench by
Defect / Contamination
Hydrogen Q-Disease
Hydrogen
Low Field Q-Drop
?
Medium Field Q-Drop
Oxygen
High Field Q-Drop
Oxygen / Grain Boundary
Global Heating
Contamination
Q-Switch
Defect / Contamination
Electron Field Emission Defect / Contamination
Electron Multipacting
Contamination
Parasitic Mode Excitation Field Emission
Shuichi Noguchi, KEK
6-th ILC School, November 2011
14
Quench
Thermal Magnetic Breakdown
DC Case
RF Case ???
Type-I
HC
HRF
?
Meisner State
H
Type-II
HC3
Normal State
HC2
HC Mixed State
HC1
Meisner State
Shuichi Noguchi, KEK
HC
Normal State
Flux Trapping ?
Super Heating ?
?
T
Tc
T
Meisner State
6-th ILC School, November 2011
Tc
15
Phase Diagram at Defect / Contamination
HRF
Short Pulse
Magnetic (Edge of pits, Scratch / Bump )
HCRF
Thermal Quench
( Contamination )
Normal Zone
Formation
T
THe
Shuichi Noguchi, KEK
6-th ILC School, November 2011
16
Maximum Magnetic Field
by Pulse Method Cornell
0.25, Type - I
Shuichi Noguchi, KEK
6-th ILC School, November 2011
17
Nb3Sn
Shuichi Noguchi, KEK
56, Type II
6-th ILC School, November 2011
18
Nb
0.82, Type - II
CW
Defect / Contamination？
H C , RF H C
2k
Shuichi Noguchi, KEK
4k
6-th ILC School, November 2011
19
Typical RF Superconductor
Nb
Pb
Nb3Sn
Critical Temperature
TC
（Ｋ）
9.25
7.2
18.3
Energy Gap
2Δ( 0 ) / kBTc
3.5
3.6
4.5
Penetration Depth
λ（０）
（ｎｍ）
32
28
170
Coherence Length
ξ（０）
（ｎｍ）
39
110
3
Ginzburg-Landau Parameter
κ（０）
0.82
0.25
56
Thermo dynamical Critical Magnetic
Field
μ ０ ＨＣ
（Ｔ）
0.2
0.08
0.53
μ０ＨＣ１
（Ｔ）
0.18
Ｔｙｐｅ－Ｉ
0.02
μ０ＨＣ２
（Ｔ）
0.4
Ｔｙｐｅ－Ｉ
29
Fluxoid
Boltzman
ShuichiConstant
Noguchi, KEK
Φ0
2.068 x 10-15 Wb
-23
-1
-5
-1
k
1.38
x
10
JK
=
8.617
x
10
eV
K
Ｂ
6-th ILC School, November 2011
20
Heat Spot Model
Normal Conducting
Radius = a
T
TC
TC,RF
THe
a
Shuichi Noguchi, KEK
6-th ILC School, November 2011
r
21
Heat Spot Approximation
Sphere
2Q
Q
2Q
2Q
Nb
He
Shuichi Noguchi, KEK
6-th ILC School, November 2011
22
Spot Loss
T
Loss
6
RS 2
Loss ; Q
H S a2
2
RS H S2 a 2
Q
T r
2 r
4 r
5
4
T (r=a)
0.2 W
; 50 W / m k
a ;10 m m, RS ; 5 m
3
Loss
2
0.1 W
1
0
Shuichi Noguchi, KEK
10
20
30
6-th ILC School, November 2011
Eacc
40 ( MV/m ) 50
23
Line Loss
T
Loss Density q
6
3.0W/cm
RS 2
Loss ; q
HS
2
q
d RS H S2
d
T r
Log
Log
r
2
r
5
4
2.0W/cm
; 50 W / m k
;10 m m, RS ; 5 m
3
2
1.0W/cm
1
0
Shuichi Noguchi, KEK
10
20
30
6-th ILC School, November 2011
Eacc
40 (MV/m)
50
24
Distributed Loss (Contamination )
Loss
T
RS 2
Loss ; q
HS
2
0.5
RS H S2 d
q
T r
d
2
0.4
q(
W/cm2
1.2
)
2m
Rs = 1m
1.0
0.8
; 50 W / m k , d 2 mm
0.3
0.6
500n
0.2
0.4
200
0.1
0
Shuichi Noguchi, KEK
10
20
30
6-th ILC School, November 2011
0.2
Eacc
40 (MV/m ) 50
25
Maximum HS by Lossy Particle
Sphere
dT
Q 1 1
2 Q 4 r
; T r THe
; r a
dr
2 r d
2
If
2 2
RS 2
R
H
a 1 1
Q
H S a 2 ; T r THe S S
2
4
r d
H S , Max
Line
4 TC THe
H
; TC ( H ) TC (0) 1
RS a 1 a d
H0
RS 2
d
T r THe
In ; q
HS ; r
r
2
q
RS H S2 d
T r THe
In ; H S , Max
2
r
Shuichi Noguchi, KEK
6-th ILC School, November 2011
2 TC THe
RS In d /
26
Maximum HS by Lossy Particle
a << d (Wall Thickness)
Normal Metal
T
4 TC THe
a
RS H S2
a
Loss
T(a)
1.37
2 x 10 4 m m
Eacc
a
Wrong Approximation
THe
r
Shuichi Noguchi, KEK
6-th ILC School, November 2011
27
Evolution of Normal Conducting Area
Lossy Area
Normal Conducting
Speed ?
Shuichi Noguchi, KEK
6-th ILC School, November 2011
Quench
28
Eacc
MV/m
Metallic Particle Contamination
H Max
Metallic Particle
RS = 2 m
40
Max. Gradient
30 （MV / m )
20
10
E Max
TC H TC 0
4 TC THe
RS a
375
MV/m
RS a
H
1
H0
RS ; Contaminan t Surface Resistance in m
a ; Contaminan t Radius in m m
20mm
Shuichi Noguchi, KEK
50mm
6-th ILC School, November 2011
Radius
100mm
29
Defect
Eacc
MV/m
h =1
40
30
20
10
H Max
Metallic Particle
2 m, TC = 9.3k
Max. Gradient
（MV / m )
h = 1.5
TC H TC 0
E Max
H
1
H0
4 TC THe
RS a
375
MV/m
RS a
By H Field Enhancement
RS ; Contaminan t Surface Resistance in m
a ; Contaminan t Radius in m m
20mm
Shuichi Noguchi, KEK
50mm
6-th ILC School, November 2011
Radius ,(Depth, Height )
100mm
30
Correlation of spot size and heating
(Rough estimation)
Relation of Spot size and Heating detected by T-map
( Preliminary result )
STF Baseline cavity #4 : After Phase 1.0 project
#1-cell equator, t=087 degree
100
Height [um]@96
Depth [um] Pit @Heating
200
Niobium Material
Height [um] Bump @Heating
50
Height [um] Bump @No Heating less than 30 ~ 39MV/m
Depth or Height [um]
Depth [um] Pit @No Heating less than 20 ~ 30MV/m
150
Height [um]
Depth [um] Pit @No Heating less than 30 ~ 39MV/m
Wall Gradient
0
Depth
Pit
-50
Heating observed < 23 MV/m
100
Plotted line
Diameter
Vac. side
-100
600
Wall Gradient: 22 deg
800
1000
1200
1400
Z-axis [um]
Wall Gradient:11 deg
50
No Heating less than ~30MV/m
0
100 200 300 400 500 600 700 800 900
Larger, deeper (or higher) pits
(or bumps) seem to cause
quenches.
However,
* Not all of the optically observed
defects lead to problems.
Diameter [um]
* Note: preliminary results of
analysis which utilizes *both* the piSample: MHI-01 ~ MHI-09, AES-01 : 10 cavities.
mode and pass-band measurements.
Number of cell = 90 cells, Number of detected spot = 49 spots.
Shuichi Noguchi, KEK
6-th ILC School, November 2011
31
31
STF K. Watanabe, Sept. 22 2009, SRF2009 in Berlin
Eacc
Quench Evolution
W ~ 100 J
Normal-conducting Area
~ cm2
Temperature, ~ 50k
Quench
~ msec.
Shuichi Noguchi, KEK
6-th ILC School, November 2011
Time
32
Examples of Lossy Area
Foreign Material
Shuichi Noguchi, KEK
Edge of Large Pit
Scratch / Bump
6-th ILC School, November 2011
Contamination
33
Quench Evolution at Bump & Pit
Pit
Magnetic Field
Field Enhancement
Smaller
Bump
Shuichi Noguchi, KEK
6-th ILC School, November 2011
34
Bump
Q 1 1
T r THe
; r a
2 r d
If
2
2 2
RS
R
H
1
2
2
S
S a 1
H S a ; T r THe
Q
2
4
r d
H S , Max
1
4 TC THe
H
; TC ( H ) TC (0) 1
RS a 1 a d
H0
Field Enhancement
T
H
r
Nb
Shuichi Noguchi, KEK
6-th ILC School, November 2011
35
Pit
T r THe
Q 1 1
; r a
2 r d
RS
RS 2 H S2 a 1 1
2
H S 2 a ; T r THe
Q
2
2
r d
H
H S , Max
1
2 TC THe
H
; TC ( H ) TC (0) 1
RS 1 a d
H0
T
H
r
Shuichi Noguchi, KEK
6-th ILC School, November 2011
36
Q-Value ; Surface Resistance
RS RBCS Rres H
ＢＣＳ
Contamination, Irregularity
Fluxoid Trap
Hydrogen
H Q-Dieses
Oxygen
Q-Slope
Grain Boundary
Lattice Orientation
Shuichi Noguchi, KEK
6-th ILC School, November 2011
37
Thermal Analysis
BCS
+ Residual Resistance Loss
Localized Normal Loss
Distributed Normal Loss
Effect of Flux Trap
Shuichi Noguchi, KEK
6-th ILC School, November 2011
38
Distributed Loss
1 d
T THe q
d
Vacuum
Loss q
Shuichi Noguchi, KEK
Liquid He
Thermal Conduction
Thermal Transfer
~ １ W / cm.k
~ 1 W / cm2.k
6-th ILC School, November 2011
39
T
T
q
T
Vacuum
０
Shuichi Noguchi, KEK
Niobium
d Helium
6-th ILC School, November 2011
d
q
z
40
Cooling Efficiency
Temperature
Mapping
System
(SRF93’)
He-I / He-II
He-II
10
10
9
He-I
10
8
0
2.17K
10
20
30
Eacc [MV/m]
4.2K Noguchi, KEK
Shuichi
1.8K
1.8 K
4.2 K
E-quench (T)
E-rf limit
2.17 K
40
50
-point
40
K-14
MK-0
C-3
M-1
30
20
10
0
He-II
1.5
2
.
He-I
2.5
3
3.5
He - Temperature [K]
Q, Heat flux [W/cm 2]
Q0
50
Eacc-quench [MV/m]
10
10
Quench Limit
K-14 Cavity
11
4
4.5
6-th ILC School, November 2011
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
1.5
K-14 Cavity
Heat Flux
Heat flux -Quench
Heat flux -rf power
(no Quench)
2
(EPAC96’)
2.5
3
3.5
4
He - Temperature [K]
4.5
41
Global Heating
RS
q
HS
2
q
2
(W / cm2)
#1 Baseline Cavity ; 1'st Vertical Test
Rs
Rbcs
Geometrical Factor = 277.
10-7
Rs
1 d
T THe q
10-6
Rres = 11.5 n
10
-8
10
-9
Rbcs (T)
0.2
0.25
0.3
0.35
0.4
0.45
1/T [1/K]
0.5
0.55
T
0
THe
Shuichi Noguchi, KEK
6-th ILC School, November 2011
42
0.6
Global Heating
q
(W / cm2)
RS
q
HS
2
2
Even Defect Free Cavity
Field Rise
1 d
T THe q
T
THe
Shuichi Noguchi, KEK
6-th ILC School, November 2011
43
Q – Drop / Increase of RS
Surface Temperature Rise by Loss
Hydrogen Absorption; Niobium Hydroid
Flux Trap
Oxygen
Nitrogen
Shuichi Noguchi, KEK
6-th ILC School, November 2011
44
Field Emission ( Tunneling Effect )
Nb
Vacuum
Fowler-Nordhaim Equation
B 1.5
; DC
j(E)
exp
E
A E2
E
I ESP
A S ESP
2.5 exp B 1.5 ;
E
SP
RF
; Field Enhancemen t Factor
Electron
Shuichi Noguchi, KEK
Metallic Particle on Surface ; ~100
6-th ILC School, November 2011
45
Fowler-Nordheim Plots
I
Log 2.5
ESP
I
1
Log 2.5
ESP ESP
Single Emitter
~ 100, S ~ 1mm2
Metallic Particle
Sulfur, Thick Nb Oxide
1
E SP
Shuichi Noguchi, KEK
6-th ILC School, November 2011
46
SEM Observations
SEM Images of Beam Pipe Sample
EPed in Cavity EP 1 Experiment (Fresh EP
Acid)
EPed in Cavity EP 2 Experiment (Aged EP
Acid)
Surfaces were covered with many particles.
Particles size was several sub-micrometers to few micrometers.
A high density of particles was observed on the surfaces treated with aged EP
Shuichi Noguchi, KEK
6-th ILC School, November 2011
47
acid.
47
P.V. Tyagi
Electron Multipacting
Resonance Electron Multiplication, Closed Trajectory
Common Phenomena in High Power RF Devices
Secondary Emission Coefficient > 1
E,H
Electron
Trajectory
Two Point
Field
Strength
Phase
One Point
Shuichi Noguchi, KEK
Kinematical Condition
For Symmetric Trajectory
6-th ILC School, November 2011
48
Passband Excitation
Shuichi Noguchi, KEK
6-th ILC School, November 2011
49
Diagnostics
to Localize Defect
Shuichi Noguchi, KEK
6-th ILC School, November 2011
50
T-Mapping (1)
T-mapping system: ~600 Allen-Bradley C-resistors
Shuichi Noguchi, KEK
6-th ILC School, November 2011
51
Temperature Mapping, cont’d
= First rotating T-mapping system
implemented at CERN, used in
subcooled helium
= T signal 10 x larger than in
saturated He, best conditions T> T
p ~ 1000 torr
= increase in heat transfer resistance
from metal to He bath
= absence of nucleate boiling therefore
no micro-convection due to bubbles
= surface temperature increases
compared to saturated He
= T-sensors are thermally decoupled
Shuichi Noguchi, KEK
6-th ILC School, November 2011
52
Q0 = 6.0 109
Eacc = 20.6 MV/m
0.2
0.18
0.16
0.14
0.12
0.1
T (K)
0.08
Large grain CEBAF Single cell cavity 25mm BCP 1:1:2
1
1E+11
T=2.0 K
7
4
0.06
T=1.7 K
13
10
0.04
S13
S11
S9
S7
S5
S3
S1
34
31
28
25
Top Iris
S15
Q0
0
22
Azimuth
19
16
0.02
1E+10
Bottom
Iris
Equator
1E+09
0
Shuichi Noguchi, KEK
6-th ILC School, November 2011
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Bp (mT)
53
Q0 = 2.6 109
Eacc = 28.3 MV/m
4
0.4
0.36
0.32
0.28
0.24
0.2
T (K)
0.16
4
1
4
Large grain CEBAF Single cell cavity 70mm BCP 1:1:2
1E+11
0.12
7
T=2.0 K
13
10
0.08
19
Top Iris
S15
S13
S11
S9
S7
S5
S3
S1
34
31
28
25
22
0
Bottom
Iris
Q0
0.04
16
Azimuth
T=1.7 K
1E+10
Equator
1E+09
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Bp (mT)
Shuichi Noguchi, KEK
6-th ILC School, November 2011
54
X-ray Mapping
Shuichi Noguchi, KEK
6-th ILC School, November 2011
55
60 .0
PIN sensor部(図の水色) 軸方向に
各8つ+iris毎に１つ。合計82個
PIN numbering(オレンジはiris部)
345.5
PIN9
PIN10
PIN11
PIN18
PIN19
1-2 iris
346.504
40
334
φ268
φ400
PIN27
PIN28
PIN29
3-4 iris
PIN36
PIN37
PIN38
4-5 iris
PIN45
PIN46
5-6 iris
PIN47
φ337
φ264
φ235
PIN54
PIN55
PIN56
φ400
346.504
φ268
334
40
PIN63
PIN64
Shuichi Noguchi, KEK
fulte2
198.8deg
PIN diode
センサー部
start
0deg
stop
360deg
7-8 iris
抵抗 no.(4n)
input
抵抗 no.(4n-3) 312.8deg
(n=1—9)cellに対応
8-9 iris
PIN74
PIN81
PIN82
鳥瞰図(空洞上から)
抵抗 no.(4n-1)
fulte1
74.7deg
6-7 iris
PIN65
PIN72
PIN73
抵抗 no.(4n-2)
pickup
134.5deg
2-3 iris
PIN20
φ337
φ264
φ235
103.9
15
φ400
323
φ268
SBP-iris
PIN1
PIN2
40
φ337
φ264
φ235
回転メカsetup
LBP iris
抵抗は回転メカとともに回転する
6-th
ILC School, November 2011
各セル赤道部に９０度毎配置
従って4個×9cell＝36個配置。
その他
抵抗：上フランジ１つ
下フランジ２つ
56
PIN：上方向軸上２つ
下方向軸上２つ
by H.Sakai (ERL Group)
全体
Shuichi Noguchi, KEK
センサー取り付け様子
6-th ILC School, November 2011
57
57
Xray-mapping (No.5) (7/9Pi-mode ,Eacc=13.1MV/m, Q0=6.6*10^9)
PIN1-27 (上から順番) (1-3cell)
Iris 1-2cell
PIN55-82 (上から順番) (7-9cell)
Iris 8-9cell
Iris 2-3cell
8-9cell 前後に多数の
radiation traceが
見られる。
Iris のみ (上から PIN10,19,28,37,46,55,64,73,82)
PIN28-54 (上から順番) (4-6cell)
Iris 8-9cell
Iris 1-2cell
Iris 2-3cell
Shuichi Noguchi, KEK
6-th ILC School, November 2011
58
58
Xray-mapping (No.8) (6/9Pi-mode ,Eacc=17.0MV/m, Q0=6.2*10^9)
PIN1-27 (上から順番) (1-3cell)
PIN55-82 (上から順番) (7-9cell)
7-9cellにかけて
310-320度に
連続的にradiation
traceが見られる。
2cell
7-8cell
8-9cell
上のcellのradiationがなくなったか？
Iris のみ (上から PIN10,19,28,37,46,55,64,73,82)
PIN28-54 (上から順番) (4-6cell)
4-5cell
4-5cell
3-4cell
7-8cell
8-9cell
Shuichi Noguchi, KEK
6-th ILC School, November 2011
59
59
Xray-mapping (No.10) (2nd Pi-mode ,Eacc=13.9MV/m, Q0=5.5*10^9)
PIN1-27 (上から順番) (1-3cell)
PIN55-82 (上から順番) (7-9cell)
Iris 8-9cell
(PIN73)
Iris 2-3cell
9cell側iris付近(PIN 74)
Iris 1-2cell
PIN28-54 (上から順番) (4-6cell)
Iris 3-4cell
Iris 2-3cell
Iris 8-9cell
Iris 4-5cell
Iris 4-5cell
Iris 3-4cell
Iris 5-6cell
Iris 5-6cell
Shuichi Noguchi, KEK
6-th ILC School, November 2011
Iris 1-2cell
60
60
Xray-mapping (No.10) (２次元mapping例)(2nd Pi-mode ,Eacc=13.9MV/m, Q0=5.5*10^9)
Shuichi Noguchi, KEK
6-th ILC School, November 2011
61
前頁のグラフを２次元の図になおすと上図のようになる。Iris部が大きいのがわかる。
Second Sound
Two Fluid Helium
Normal He Flow
Heat Spot
Super He Flow
Shuichi Noguchi, KEK
6-th ILC School, November 2011
62
Shuichi Noguchi, KEK
6-th ILC School, November 2011
63