Theoretical and Experimental studies

1
Theoretical and Experimental studies on energy
transfer in Couplers for Superconducting RF
Cavities
Nawin Juntong
20-December-2007
2
Where I come from?
- Photoemission Spectroscopy - X-Ray Lithography
- X-ray Absorption Spectroscopy
National Synchrotron Research Center is a
research institute operating the Siam Photon
Source (SPS), a  1.2 GeV synchrotron light
source.
3
My Work
Pictures from - Peter McIntosh, ERLP and 4GLS at
Daresbury, SRF2007,Beijing (15-19 Oct 2007) and
XFEL website
4
Scope of Work

• 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.

Work Schedule

• 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.

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
5
Simulation Results
HFSS 8.5 results comparison with Wanzenberg
paper. Simulation on TESLA mid cell geometry.
Type Band f0/GHz f0/GHz f0/GHz fp/GHz fp/GHz fp/GHz
Type Band 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
MMonopole, DDipole
0.16
6
Circuit model theory
Single chain
Only TE or TM field
Double chain
Coupling between TE and TM field
7
Apply Circuit model Theory
Monopole mode - use single chain model
  HFSS 8.5 HFSS 8.5 HFSS 8.5 Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model
  1stband 2ndband 3rdband 1stband 1stband 2ndband 2ndband 3rdband 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 ()  Max.Diff ()  Max.Diff ()  0.0054   0.1619   0.1697
  HFSS 8.5 HFSS 8.5 HFSS 8.5 Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model Single Chain Circuit model
  4thband 5thband 6thband 4thband 4thband 5thband 5thband 6thband 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 ()  Max.Diff ()  Max.Diff ()    1.1339   1.3417   0.2947
8
TM
TE
Dipole mode use double chain model
TM
TE
  HFSS 8.5  HFSS 8.5  Circuit model Circuit model Circuit model Circuit model
  1st band 2nd band 1st band 1st band 2nd 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 () Max.Diff ()   0.1629   0.1187
9
Dispersion Curves
Red-Monopole Blue-Dipole
10
-END- Thank you