cavity measurements by aaron cheng 4 may 2007. 2 overview rf measurements waveguide-coax transition
TRANSCRIPT
Cavity Measurements
By
Aaron Cheng
4 May 2007
2
Overview
RF measurements Waveguide-coax transition
3
RF measurements
FETS 4-vane RFQ copper cold model in Imperial College
4
RF measurements
Input couplers used
5
RF measurements
Some coupling stability problems
6
RF measurements
Some coupling stability problems
7
Waveguide-coax transitionStudying doorknob wg-coax
•Coupler with coaxial RF window
•S11 = -14.7527dB
•S21 = -0.14029dB
Description Value [mm]
radius of coax conductor 33.5
Radius of coax insulator 77
coax line length 300
doorknob distance from wg end plate
231.84
doorknob height 139.57
doorknob radius 206.91
thickness of doorknob wall 10.6
waveguide length 1000
window position from waveguide 10
window thickness 6
8
Studying doorknob wg-coax
•Coupler with planar RF window
•S11 = -35.2005dB
•S21 = -0.000034dB
Description Value [mm]
radius of coax conductor 33.5
Radius of coax insulator 77
coax line length 300
Doorknob distance from wg end plate
287.89
doorknob height 139.57
doorknob radius 200
thickness of doorknob wall 10.6
waveguide length 1000
window position from doorknob 96.25
window thickness 3.5
Waveguide-coax transition
9
Studying doorknob wg-coax
•Coupler with planar RF window
•S11 = -33.7465dB
•S21 = -0.00015221dB
Parameter Value [mm]
radius of coax conductor 33.5
Radius of coax insulator 77
coax line length 300
coax distance from waveguide end plate 231.84
doorknob height 139.57
doorknob radius 171.27
thickness of doorknob wall 10.6
waveguide length 1000
window inner radius 229
window thickness 6
Waveguide-coax transition
10
Studying t-bar wg-coax
•Coupler with coaxial RF window
•S11 = -59.6085dB
•S21 = -0.018748dB
Description Value [mm]
coax line conductor radius 33.5
coax line insulator radius 77
coax line length -200
t-shape distance from waveguide end-plate
121.76
t-shape height 153
window height 11
position of window from waveguide 128.5
Waveguide-coax transition
11
Studying t-bar wg-coax
•Coupler with planar RF window
•S11 = -27.1593dB
•S21 = -0.0095028dB
Description Value [mm]
coax line conductor radius 33.5
coax line insulator radius 77
coax line length -200
distance from waveguide end-plate 120.5
t-shape height 144.42
window thickness 8.7
position of window from t-bar center 45
Waveguide-coax transition
12
Thermal analysis Vacuum pumping ports and requirements Electron probes and threshold Connecting flanges
Waveguide-coax transition
13
Summary
1. Bead pull measurement to be conducted more with unbrazed and brazed RFQ
2. Waveguide-Coax transition will stop at current status until after PAC conference
3. Other matters:
• Microwave signal generator and amplifier have arrived, currently placed in RAL