Measurement of input coupler matching of a loaded storage ring single-cell cavity
In the APS storage ring cavities, magnetic loop type input couplers are used. The loaded Q of a cavity varies as the beam loading changes. The beam loading changes the cavity input impedance. Therefore, the input coupler must be adjusted to maintain a good impedance match. Measurements have been made to determine the coupler loop position (depth of penetration) with respect to various loading conditions in a storage ring single-cell cavity. An input coupler was inserted into the storage ring single-cell cavity at various loaded Q points, then matched. The relationship between the coupling coefficient, {Beta}, and the gap width, where gap width is the separation between the input coupler flange and the cavity port flange, was studied. A coupling coefficient is defined where Q{sub O} is the unloaded Q and Q{sub L} is the loaded Q, repectively. Depending on the extent of deQing of the fundamental mode in the single-cell cavity, the input coupler was positioned further in or out of the cavity accordingly to achieve matching at 50 {Omega}. Damping the cavity simulates the beam loading when the beam passes through the single-cell cavities.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 176793
- Report Number(s):
- LS-247; ON: DE96004543; TRN: 96:001136
- Resource Relation:
- Other Information: PBD: 14 Aug 1995
- Country of Publication:
- United States
- Language:
- English
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