2011 Particle Accelerator Conference - List of Authors (Kustom, R.)

Paper	Title	Page
TUP242	Electron Cloud Issues for the APS Superconducting Undulator	1283
	K.C. Harkay, Y. Ivanyushenkov, R. Kustom, E.R. Moog, E. Trakhtenberg ANL, Argonne, USA L.E. Boon, A.F. Garfinkel Purdue University, West Lafayette, Indiana, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. 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 Angstromquelle Karlsruhe (ANKA), also an electron ring, suggests that electron multipacting is consistent with the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. At APS it was found 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 the 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.

TUP245	Comparison of Standard S-Glass and Ceramic Coating as Insulation in Short-Period Superconducting Undulators Based on Nb3Sn	1292
	S.H. Kim, C.L. Doose, M. Kasa, R. Kustom, E.R. Moog ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This paper compares calculated on-axis fields for short- period superconducting undulators (SCUs) using Nb3Sn superconductor with two different insulation thicknesses, 0.02 mm and 0.05 mm. When the insulated conductor diameter remained the same, the on-axis fields using the thinner insulation were higher by about 8 – 15% for a period range of 15 – 10 mm. When the conductor diameters with the thicker insulation were made larger than the conductors with the thinner insulation, the differences were reduced to be about 6 – 12%.

WEP185	Properties of Longitudinally Uniform Beam Waveguides	1834
	Y.W. Kang ORNL, Oak Ridge, Tennessee, USA R. Kustom, R. Nassiri ANL, Argonne, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. Beam waveguide (BWG) geometry with two longitudinally uniform concave reflectors can support quasi-optical transverse resonances of electromagnetic waves and longitudinal power transmission. The quasi-optical resonance in BWG can be treated as a Gaussian beam. The BWG are often known to have high Q-factors while operating in higher order modes. The latest interests on these beam waveguides are the application for microwave or millimeter wave undulators for synchrotron radiation. The general properties of the BWG are discussed with the field solutions and dispersion properties derived with elliptical beam waveguides approximation. Potential applications of BWG for supporting circularly polarized wave are discussed.

Paper

Title

Page

Electron Cloud Issues for the APS Superconducting Undulator

1283

K.C. Harkay, Y. Ivanyushenkov, R. Kustom, E.R. Moog, E. Trakhtenberg
ANL, Argonne, USA
L.E. Boon, A.F. Garfinkel
Purdue University, West Lafayette, Indiana, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
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 Angstromquelle Karlsruhe (ANKA), also an electron ring, suggests that electron multipacting is consistent with the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. At APS it was found 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 the 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.

TUP245

Comparison of Standard S-Glass and Ceramic Coating as Insulation in Short-Period Superconducting Undulators Based on Nb3Sn

1292

S.H. Kim, C.L. Doose, M. Kasa, R. Kustom, E.R. Moog
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
This paper compares calculated on-axis fields for short- period superconducting undulators (SCUs) using Nb3Sn superconductor with two different insulation thicknesses, 0.02 mm and 0.05 mm. When the insulated conductor diameter remained the same, the on-axis fields using the thinner insulation were higher by about 8 – 15% for a period range of 15 – 10 mm. When the conductor diameters with the thicker insulation were made larger than the conductors with the thinner insulation, the differences were reduced to be about 6 – 12%.

WEP185

Properties of Longitudinally Uniform Beam Waveguides

1834

Y.W. Kang
ORNL, Oak Ridge, Tennessee, USA
R. Kustom, R. Nassiri
ANL, Argonne, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Beam waveguide (BWG) geometry with two longitudinally uniform concave reflectors can support quasi-optical transverse resonances of electromagnetic waves and longitudinal power transmission. The quasi-optical resonance in BWG can be treated as a Gaussian beam. The BWG are often known to have high Q-factors while operating in higher order modes. The latest interests on these beam waveguides are the application for microwave or millimeter wave undulators for synchrotron radiation. The general properties of the BWG are discussed with the field solutions and dispersion properties derived with elliptical beam waveguides approximation. Potential applications of BWG for supporting circularly polarized wave are discussed.