Beam impedance measurements on the ALS sector tank [electronic resource].
- Washington, D.C : United States. Dept. of Energy. Office of Energy Research, 1990.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- Pages: (5 pages) : digital, PDF file
- Additional Creators:
- Lawrence Berkeley National Laboratory
United States. Department of Energy. Office of Energy Research
United States. Department of Energy. Office of Scientific and Technical Information
- The 10 m long ALS curved sector tank is formed from two shells out of which the beam chamber is machined. Vacuum pumping and photon stops are located in an antechamber connected to the beam tube through a 1cm slot. In order to determine whether the beam is significantly coupled to the antechamber, measurements of longitudinal beam impedance were performed up to 26 GHz, well above the cutoff frequency of the beam pipe. Two different schemes were used: In the first, the wire method was adapted for use above cutoff; in the second, the impedance was detected from the response to TM-waves propagated in the aperture without a wire. Temperature at various locations in the setup was recorded for later phase corrections. Antennas were placed in the antechamber to detect radiated power or possible resonances. A reference measurement was made with the slot sealed by a flexible gasket of knitted wire. The seal was then removed and the response with antechamber recorded. The response was checked by inserting obstacles of known impedance. Both measurement methods provided low numbers with Z/n<0.001 Ohm over the whole frequency range. No resonances attributable to the antechamber were observed. 3 refs., 6 figs.
- Published through SciTech Connect.
2. European particle accelerator conference, Nice (France), 11-16 Jun 1990.
Lambertson, G.R.; Voelker, F.; Rimmer, R.A.; Goldberg, D.A.; Jacob, A.F.
- Funding Information:
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