Theoretical and Experimental studies on energy transfer in Couplers for Superconducting RF Cavities Nawin Juntong 20-December-2007.

Theoretical and Experimental studies

on energy transfer in Couplers for

Superconducting RF Cavities

Nawin Juntong

20-December-2007

National Synchrotron Research Center is a research institute operating the Siam Photon Source (SPS), a  1.2 GeV synchrotron light source.

Where I come from?

- Photoemission Spectroscopy - X-Ray Lithography - X-ray Absorption Spectroscopy

Pictures from - Peter McIntosh, ERLP and 4GLS at Daresbury, SRF2007,Beijing (15-19 Oct 2007) and XFEL website

My Work

ERLP Cryomodule @ Daresbury

XFEL Coupler

High peak power, pulsed operation

7-cell 1.3GHz TESLA type Cornell Coupler

High average power CW

-Study of specifications and performances (Thermal and RF) on a different RF coupler designs .

-Use RF codes, HFSS, GdfidL and ECHO 2D,to determine EM fields properties, wakefields, wake potential, loss factors and kick factors.

-Experimental Tests of Coupler Kicks on ERLP.

Scope of Work

Work Schedule

January – February 2008- Understand cleanroom procedures and assist with the cleaning and assembly of XFEL Coupler and participate in RF testing.January – June 2008- Assess the Antenna shape and coupling effects of different Antenna designs.June 2008 – December 2009- Assessment of Coupler kicks, calculations and experiments

October-December 2007- Use HFSS code calculate mode frequencies on monopole and dipole modes of TESLA type cavity.- Apply circuit model theory on this simulation.

Simulation Results

Type Band #0/GHz /GHz

Paper Results Diff./MHz Paper Results Diff./MHz

M 1 1.2755 1.27690 1.40 1.2996 1.30119 1.59

D 1 1.6197 1.61941 0.29 1.7920 1.79549 3.49

D 2 1.8877 1.89167 3.97 1.8261 1.82556 0.54

M 2 2.4576 2.45989 2.29 2.3789 2.38056 1.66

D 3 2.5782 2.58126 3.06 2.4713 2.47264 1.34

M 3 2.6704 2.67319 2.79 2.7730 2.77581 2.81

D 4 3.0333 3.03531 2.01 2.8134 2.81843 5.03

D 5 3.1231 3.12332 0.22 3.0802 3.08073 0.53

D 6 3.3419 3.34685 4.95 3.3595 3.36457 5.07

M 4 3.6603 3.66529 4.99 3.3871 3.39225 5.15

0.16%

HFSS 8.5 results comparison with Wanzenberg paper.

Simulation on TESLA mid cell geometry.

M=Monopole, D=Dipole

Circuit model theory

Single chain

Double chainCoupling between TE and TM field

Only TE or TM field

HFSS 8.5 Single Chain Circuit model

1stband 2ndband 3rdband 1stband 2ndband 3rdband

Phase diff. F(GHz) F(GHz) F(GHz) F(GHz) Diff(MHz) F(GHz) Diff(MHz) F(GHz) Diff(MHz)

0 1.27690 2.45989 2.67319 1.27690 0.00 2.45989 0.00 2.67319 0.00

30 1.27851 2.45285 2.68128 1.27848 0.03 2.45433 1.48 2.67971 1.57

60 1.28288 2.43577 2.70190 1.28284 0.04 2.43932 3.55 2.69777 4.13

90 1.28894 2.41534 2.72768 1.28887 0.07 2.41925 3.91 2.72305 4.63

120 1.29505 2.39722 2.75207 1.29499 0.06 2.39967 2.45 2.74905 3.02

150 1.29954 2.38490 2.76946 1.29952 0.02 2.38564 0.74 2.76856 0.90

180 1.30119 2.38056 2.77581 1.30119 0.00 2.38056 0.00 2.77581 0.00

  Max.Diff (%)  0.0054   0.1619   0.1697

HFSS 8.5 Single Chain Circuit model

4thband 5thband 6thband 4thband 5thband 6thband

Phase diff. F(GHz) F(GHz) F(GHz) F(GHz) Diff(MHz) F(GHz) Diff(MHz) F(GHz) Diff(MHz)

0 3.66529 3.75546 3.92133 3.66529 0.00 3.75546 0.00 3.92133 0.00

30 3.61966 3.79303 3.93489 3.64490 25.24 3.76210 30.93 3.94039 5.50

60 3.55064 3.83183 3.98308 3.59090 40.26 3.78042 51.41 3.99390 10.82

90 3.48719 3.84834 4.05869 3.52085 33.66 3.80588 42.46 4.07065 11.96

120 3.43665 3.85491 4.14032 3.45476 18.11 3.83186 23.05 4.15200 11.68

150 3.40369 3.85760 4.20893 3.40867 4.98 3.85122 6.38 4.21474 5.81

180 3.39225 3.85838 4.23843 3.39225 0.00 3.85838 0.00 4.23843 0.00

  Max.Diff (%)    1.1339   1.3417   0.2947

Apply Circuit model TheoryMonopole mode - use single chain model

HFSS 8.5  Circuit model

1st band 2nd band 1st band 2nd band

Phase F(GHz) F(GHz) F(GHz) Diff(MHz) F(GHz) Diff(MHz)

0 1.61941 1.89167 1.61941 0.00 1.89167 0.00

30 1.62727 1.89048 1.62758 0.31 1.89021 0.27

60 1.64956 1.88652 1.65097 1.41 1.88557 0.95

90 1.68396 1.87923 1.68628 2.32 1.87700 2.23

120 1.72530 1.86550 1.72811 2.81 1.86330 2.20

150 1.76764 1.84491 1.76947 1.83 1.84348 1.43

180 1.79549 1.82556 1.79549 0.00 1.82556 0.00

  Max.Diff (%)   0.1629   0.1187

TETM

TM

TE

Dipole mode – use double chain model

Dispersion Curves Red-Monopole

Blue-Dipole

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