Download - X-band Structures Test Results at NLCTA
X-band Structures Test Results at NLCTA
Faya Wang Chris Adolphsen, Christopher Nantista
9-Feb-11
Time Structure Note Performance
12/09 -4/10TD18vg2.3-Disk
SLAC_1Cells by KEK,
Assembled at SLAC
Fair: after 1000 hours, 79 MV/m, 230 ns at LC DBR spec – no hot
cells
8/10 – 9/10T18vg2.6-Disk
CERN_2CERN Built
Fair: after 550 hours, 85 MV/m, 230 ns at LC DBR spec – no hot
cells
9/10 – 12/10T24vg1.8Disk
SLAC_1SLAC Built
Fair: after 600 hours, 82 MV/m, 230 ns at LC DBR spec – no hot
cells
11/10 Dual-Mode Cavity – 1st Run SLAC Built OnlyTEM mode, Heavily detuned
2/11 Dual-Mode Cavity – 2nd Run
Re-tuned, two modes are at 11.424 TBD
Structure Performance Summary
LC DBR = 4e-7 pulse/m
0 2 4 6 8 10 12 14 16 180
50
100
150
200
250
iris number
P [
MW
] (b
lack
), E
s (
gre
en),
Ea (
red
) [M
V/m
],
T
[K
] (b
lue)
, S
c*50
[MW
/mm
2 ] (m
agen
ta)
29.1
47.0
155
226
3.2
4.4
79
120
57.5
34.3
Pinload = 57.5 MW, P
outload = 34.3 MW
Eff = 0.0 % tr = 0.0 ns, t
f = 0.0 ns, t
p = 100.0 ns
0 2 4 6 8 10 12 14 16 180
50
100
150
200
250
iris number
P [
MW
] (b
lack
), E
s (
gre
en),
Ea (
red
) [M
V/m
],
T
[K
] (b
lue)
, S
c*50
[MW
/mm
2 ] (m
agen
ta)
8.1 12.5
148
232
2.7
4.4
76
126
53.0
37.4
Pinload = 53.0 MW, P
outload = 37.4 MW
Eff = 0.0 % tr = 0.0 ns, t
f = 0.0 ns, t
p = 100.0 ns
0 4 8 12 16 20 24240
50
100
150
200
250
iris number
P [
MW
] (b
lack
), E
s (
gre
en),
Ea (
red
) [M
V/m
],
T
[K
] (b
lue)
, S
c*50
[MW
/mm
2 ] (m
agen
ta)
7.5 8.4
176
205
3.03.2
90
108
41.1
23.4
Pinload = 41.1 MW, P
outload = 23.4 MW
Eff = 0.0 % tr = 0.0 ns, t
f = 0.0 ns, t
p = 100.0 ns
T18
TD18
T24
100 MV/m, Average Gradient18 series, strong tapering24 series, high efficiency
Surface Magnetic Field of TD18
BDR Pulse Heating Dependence of TD18
20 30 40 50 60 70 80 90 10010
-7
10-6
10-5
10-4
10-3
Peak Pulse Heating at Last Cell (K)
BD
R (
1/p
uls
e/m
)
T18, 900 hrsTD18, 100 MV/m @ 100ns,870hrsTD18, 100MV/m@ 150ns, 960hrs TD18, 100MV/m@200ns, 750hrsTD18, 115MV/m@150ns, 550hrsTD18, 120MV/m@150ns, 570hrsTD18, 100MV/m@230ns, 700hrsTD18, 105MV/m@230ns, 680hrsTD18, 100MV/m@50ns
110 MV/m
Difference between T and TD18 explained?
Points of enhanced breakdown rate in TD18 tested at SLAC probably identified.Location is point of maximum surface current.
Damping waveguide
Inner cell
Origin of problem thought to be current carrying capacity of bond joint.TD24 has lower surface current and joint is receiving renewed scrutiny.
W. WuenschCLIC ACE2-2-2011
0 1 2 3 4 5 6 7 80
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Fra
ctio
n o
f bre
akd
ow
n e
ven
ts a
fter
INT
LK
SLAC - TD18KEK - TD18
Breakdown sequence statisticsBoth sets of measurements were made on TD18s
SLAC: 100 MV/m @ 200ns
Start of Operation 09/21/10
Vacuum History
Start of Operation 08/02/10
T18_CERN_2
T24_SLAC
Start of Operation 03/12/09
TD18_SLAC
9172: for input load 9186: structure9180: right output load9184: left output load9160: WG to structure
-150 -100 -50 0 50 100 150-5
0
5
10
15
20
25
30
35
40
45
Reflected Phase: Deg
Fill
ing
time
for
diff
eren
t ce
ll: n
s
Breakdown Location distribution
-150 -100 -50 0 50 100 150-5
0
5
10
15
20
25
30
35
40
Reflected Phase: Deg
Fill
ing
time
for
diff
eren
t ce
ll: n
s
-150 -100 -50 0 50 100 150
0
10
20
30
40
50
60
Reflected Phase: Deg
Fill
ing
time
for
diff
eren
t ce
ll: n
s
T18_Cern_2TD18_SLAC
T24_SLAC
Structure Performance Summary at 230 ns
80 85 90 95 100 105 110 11510
-7
10-6
10-5
10-4
10-3
Gradient (MV/m)
BD
R (
1/p
uls
e/m
)
T18 250 hr
T18 1200 hr
T18 900 hr
T18 1400 hrT24 600 hr
T24 400 hr
TD18 1200 hr
T18 500 hr
T18-CERN2 500 hr
TD18 700 hr
4e-7 pulse/m
X-band Dual-Mode CavityTE011
TEM
E-field
B-field
TE011
TEM
Chris Nantista
11.418 11.42 11.422 11.424 11.426 11.428 11.43 11.432 11.434-70
-60
-50
-40
-30
-20
-10
0
Frequency (GHz)
S P
aram
eter
(dB
)
11.418 11.42 11.422 11.424 11.426 11.428 11.43 11.432 11.434
-25
-20
-15
-10
-5
0
Frequency (GHz)
S P
aram
eter
(dB
)
Crosstalk: -22.75 dB (0.531%)Minimum S11: -12.17 dB (6.07%) @ 11.4260 GHzMinimum S22: -25.33 dB (0.293%) @ 11.4260 GHz
Tuning Cold Test Data
TEMfr = 11.426 GHzQ0 = 9,334.8Qe = 8,334.2QL = 4,403.1 (b = 1.1201)
TEfr = 11.426 GHzQ0 = 14,935Qe = 24,913QL = 9,337.5 (b = 0.5995)
Chris Nantista
TE011 and TEM3 modes are simultaneously excited
0 500 1000 1500 20000
5
10
15
20
25
30
Time (ns)
Input Forward Power for TEM3 (MW)Peak Surface Field of TEM3 /10 (MV/m)Peak Pulsed Heating of TEM3 /3 (K)Input Forward Power for TE011 (MW)Peak Pulse Heating of TE011 /3 (K)
0 500 1000 1500 20000
1
2
3
4
5
6
Time (ns)
Pow
er (M
W)
Measured Input FWDInput REFLDissipated in CavityMeasured InpRefl
TEM High Power Test
0 10 20 30 40 50 60 700
50
100
150
200
250
300
350
400
450
500
550
Time with rf on (hours)
Accumulated BKDsFlat Top (ns)Peak Surface Field (MV/m)
Dual-moded Cavity 1st Run with TEM3 Mode
Not Real Breakdown Cavity heavily detuned
TEMTE011
X-band Dual-Mode Cavity Test Setup
0 500 1000 1500 20000
1
2
3
4
5
6
7
Time (ns)
Pow
er (M
W)
Measured Input FWDMeasured Input REFLDissipated in CavityInput Refl
TE011 High Power Test
Start of Operation 31/1/11 Start of Operation 31/1/11
TE – STN1 TEM – STN2
Vacuum History
Pulsed heating is 50 K by TE011, and 63 K by TEM.The peak surface field from TEM is 200 MV/m.
Summary
. Although only 600 hrs of operation, the performance of T24_SLAC is worse than T18_SLAC even though it has lower pulsed heating.
. Surface contamination or vacuum leakage may limit the performance of T18_CERN_Disk_2. . So far, no evidence of a BDR enhancement from the added 50 deg TE mode pulsed heating in the dual-mode cavity with 200 MV/m peak TEM surface electric fields