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