X-band Structures Test Results at
NLCTA
Faya Wang
Chris Adolphsen, Christopher Nantista
9-Feb-11
Structure Performance Summary
Time
Structure
Note
Performance
12/09 -4/10
TD18vg2.3-Disk
SLAC_1
Cells by KEK,
Assembled at SLAC
Fair: after 1000 hours, 79 MV/m,
230 ns at LC DBR spec – no hot
cells
8/10 – 9/10
T18vg2.6-Disk
CERN_2
CERN Built
Fair: after 550 hours, 85 MV/m,
230 ns at LC DBR spec – no hot
cells
9/10 – 12/10
T24vg1.8Disk
SLAC_1
SLAC 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
LC DBR = 4e-7 pulse/m
250
250
205
200
176
3.2
3.0
150
T24
108
s
s
126
100
76
53.0
50
37.4
0
2
100
90
50
41.1
23.4
12.5
8.1
0
Eff = 0.0 %
tr = 0.0 ns, tf = 0.0 ns, tp = 100.0 ns
a
150
2
 T [K] (blue), S c*50 [MW/mm ] (magenta)
a
T18
148
2.7
P [MW] (black), E (green), E (red) [MV/m],
2
 T [K] (blue), S c*50 [MW/mm ] (magenta)
P [MW] (black), E (green), E (red) [MV/m],
Eff = 0.0 %
tr = 0.0 ns, tf = 0.0 ns, tp = 100.0 ns
200
Pload
= 41.1 MW, P load
= 23.4 MW
in
out
232
4.4
Pload
= 53.0 MW, P load
= 37.4 MW
in
out
8.4
7.5
4
6
8
10
iris number
12
14
16
18
0
0
4
8
12
iris number
16
20
24
2
 T [K] (blue), S c*50 [MW/mm ] (magenta)
Pload
= 57.5 MW, P load
= 34.3 MW
in
out
Eff = 0.0 %
tr = 0.0 ns, tf = 0.0 ns, tp = 100.0 ns
200
226
4.4
TD18
3.2
a
P [MW] (black), E (green), E (red) [MV/m],
250
155
150
s
120
100
79
57.5
47.0
34.3
50
29.1
0
0
2
4
6
8
10
iris number
12
14
16
18
100 MV/m, Average Gradient
18 series, strong tapering
24 series, high efficiency
Surface Magnetic Field of TD18
BDR Pulse Heating Dependence of TD18
10
BDR (1/pulse/m)
10
10
10
10
-3
-4
-5
T18, 900 hrs 110 MV/m
TD18, 100 MV/m @ 100ns,870hrs
TD18, 100MV/m@ 150ns, 960hrs
TD18, 100MV/m@200ns, 750hrs
TD18, 115MV/m@150ns, 550hrs
TD18, 120MV/m@150ns, 570hrs
TD18, 100MV/m@230ns, 700hrs
TD18, 105MV/m@230ns, 680hrs
TD18, 100MV/m@50ns
-6
-7
20
30
40
50
60
70
80
Peak Pulse Heating at Last Cell (K)
90
100
Difference between T and TD18 explained?
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. Wuensch
CLIC ACE
2-2-2011
Points of enhanced breakdown rate
in TD18 tested at SLAC probably
identified.
Location is point of maximum surface
current.
Breakdown sequence statistics
Fraction of breakdown events after INTLK
Both sets of measurements were made on TD18s
0.8
SLAC - TD18
KEK - TD18
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
1
2
3
SLAC: 100 MV/m @ 200ns
4
5
6
7
8
Vacuum History
Start of Operation 03/12/09
TD18_SLAC
T18_CERN_2
Start of Operation 08/02/10
Start of Operation 09/21/10
T24_SLAC
9172: for input load
9186: structure
9180: right output load
9184: left output load
9160: WG to structure
45
40
40
35
35
30
Filling time for different cell: ns
Filling time for different cell: ns
Breakdown Location distribution
30
25
20
15
10
TD18_SLAC
0
-150
-100
-50
0
50
Reflected Phase: Deg
100
60
50
Filling time for different cell: ns
20
15
10
5
5
-5
25
40
30
20
10
T24_SLAC
0
-150
-100
-50
0
50
100
Reflected Phase: Deg
150
150
T18_Cern_2
0
-5
-150
-100
-50
0
50
Reflected Phase: Deg
100
150
Structure Performance Summary at 230 ns
10
-3
T24 400 hr
10
TD18 700 hr
-4
T18 250 hr
BDR (1/pulse/m)
T24 600 hr
T18 1400 hr
TD18 1200 hr
10
-5
T18 900 hr
10
T18 500 hr
-6
T18-CERN2 500 hr
4e-7 pulse/m
10
T18 1200 hr
-7
80
85
90
95
100
Gradient (MV/m)
105
110
115
X-band Dual-Mode Cavity
TE011
TEM
E-field
B-field
TEM
TE011
Chris Nantista
Tuning Cold Test Data
Chris Nantista
0
0
-10
-5
S Parameter (dB)
S Parameter (dB)
-20
-10
-15
-30
-40
-50
-20
-60
-25
11.418
11.42
11.422
11.424 11.426 11.428
Frequency (GHz)
11.43
11.432
11.434
-70
11.418
11.42
11.422
11.424 11.426 11.428
Frequency (GHz)
11.43
Minimum S11: -12.17 dB (6.07%) @ 11.4260 GHz
Minimum S22: -25.33 dB (0.293%) @ 11.4260 GHz
Crosstalk: -22.75 dB (0.531%)
TE
fr = 11.426 GHz
Q0 = 14,935
Qe = 24,913
QL = 9,337.5 (b = 0.5995)
TEM
fr = 11.426 GHz
Q0 = 9,334.8
Qe = 8,334.2
QL = 4,403.1 (b = 1.1201)
11.432
11.434
TE011 and TEM3 modes are
simultaneously excited
30
25
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)
20
15
10
5
0
0
500
1000
Time (ns)
1500
2000
TEM High Power Test
6
5
Measured Input FWD
Power (MW)
4
Input REFL
Dissipated in Cavity
Measured InpRefl
3
2
1
0
0
500
1000
Time (ns)
1500
2000
Dual-moded Cavity 1st Run with TEM3 Mode
550
Accumulated BKDs
Flat Top (ns)
Peak Surface Field (MV/m)
500
450
400
350
300
250
200
150
100
50
0
0
10
20
30
40
50
Time with rf on (hours)
60
70
Not Real Breakdown
Cavity heavily detuned
X-band Dual-Mode Cavity Test Setup
TE011
TEM
TE011 High Power Test
7
6
Measured Input FWD
Measured Input REFL
5
Dissipated in Cavity
Power (MW)
Input Refl
4
3
2
1
0
0
500
1000
Time (ns)
1500
2000
Vacuum History
Start of Operation 31/1/11
TE – STN1
Start of Operation 31/1/11
TEM – STN2
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