Speaker
Katherine Harkay
(Argonne National Laboratory)
Description
The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. Operation of an SCU at ANKA, also an electron ring, suggests that electron multipacting may in part be responsible for the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. It was found at APS that while the cloud code POSINST agreed fairly well with Retarding Field Analyzer (RFA) data for a positron beam (operated 1996-98), the agreement was less satisfactory for the electron beam. The APS data suggest that the photoelectron model is not complete. Given that the heat load is a critical parameter in designing the cryosystem for the SCU and given the experience at ANKA, a study is underway to minimize the possible contribution to the heat load by the electron cloud at APS, the photoelectrons in particular. In this talk, the results from POSINST are presented. Preliminary tracking of the photon flux using SYNRAD3D for the APS SCU chamber is presented, and possible ways to mitigate the photoelectrons are discussed.
Primary author
Katherine Harkay
(Argonne National Laboratory)
Co-authors
Art Garfinkel
(Purdue University)
Elizabeth Moog
(Argonne National Laboratory)
Emil Trakhtenberg
(Argonne National Laboratory)
Laura Boon
(Purdue University)
Richard Rosenberg
(Argonne National Laboratory)
Robert Kustom
(Argonne National Laboratory)
Sara Casalbuoni
(Karlsruhe Institute of Technology)
Yury Ivanyushenkov
(Argonne National Laboratory)
