Construction and commissioning of the positron accumulator ring for the APS
- Argonne National Lab., Chicago, IL (United States)
The injector for the Advanced Photon Source (APS) consists of a 200-MeV electron linac, a 450-MeV position linac, a positron accumulator ring (PAR). and a 7-GeV synchrotron. The purpose of the PAR is to accumulate, and damp positrons from the 60Hz linac during each cycle of the 2Hz synchrotron, thus increasing the fill rate for the main ring. Construction of the PAR was recently completed, and commissioning is well underway. The PAR contains eight conventional 1.5T, flat field, 45{degrees} dipole magnets with an {approximately} 1m bending radius and no gradient: adjustment of the damping partition was achieved with 25.5{degrees} edge angles. Four families of quadrupole magnets provide focusing, with each dipole closely bracketed by two quadrupoles. Ten sextupole magnets provide both steering and chromatic correction. Extensive magnetic measurements have characterized saturation-dependent effective length in the dipoles and interaction among the closely-spaced, large-aperture dipoles, quadrupoles and sextupoles. For injection and extraction, PAR employs three delay-line kickers with {approximately} 120ns rise and fall times, and a single transformer septum magnet with a 2mm septum wall. A first-harmonic rf system is used to capture positrons and a twelfth-harmonic system provides an additional three-fold bunch compression. Diagnostics include 16 stripline beam position monitors, six fluorescent screens, dual fast/integrating current transformers, a tune measurement system, and two synchrotron light ports. Commissioning of the PAR with electrons has proceeded rapidly, starting at 150MeV and progressing to 450MeV as higher energy electrons became available. Alignment and dipole uniformity are sufficiently good that beam can be stored without the use of steering magnets. Experiments to date show excellent agreement with the machine model. Accumulation at 6Hz and extraction at 2Hz has been performed with essentially 100% efficiency.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 199760
- Report Number(s):
- CONF-941129-; TRN: 95:005652-0258
- Resource Relation:
- Conference: 13. international conference on the application of accelerators in research and industry, Denton, TX (United States), 7-10 Nov 1994; Other Information: PBD: 1994; Related Information: Is Part Of Thirteenth international conference on the application of accelerators in research and industry; Duggan, J.L.; Morgan, I.L. [eds.]; PB: 201 p.
- Country of Publication:
- United States
- Language:
- English
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