PAC2013 - List of Authors (Vasserman, I.)

Paper	Title	Page
WEPSM08	Fast-Switching Variably Polarizing Undulator	1061
	M.S. Jaski, R.J. Dejus, B. Deriy, E. Gluskin, E.R. Moog, I. Vasserman, J. Wang, A. Xiao ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357 Development of a new fast-switching Electromagnetic Variably Polarizing Undulator (EMVPU) is underway at the Advanced Photon Source (APS). The EMVPU can produce x-rays with left- and right-handed circular polarizations and horizontal and vertical linear polarizations in the energy range 400-2000 eV. The undulator will be able to switch between left- and right-handed circular polarization at 10 Hz, fast enough to allow for magnetic circular dichroism studies that rely on lock-in amplifier techniques. The handedness switch will be accomplished by switching only the vertical component of the field while the horizontal component stays constant. Details of the EMVPU and its initial experimental test models are presented.

WEPSM09	An Electromagnetic Variably Polarizing Quasi-Periodic Undulator	1064
	M.S. Jaski, M. Abliz, R.J. Dejus, B. Deriy, E. Gluskin, E.R. Moog, I. Vasserman, A. Xiao ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. An electromagnetic variably polarizing quasi-periodic undulator was installed in the Advanced Photon Source (APS) storage ring in April 2012 and has been successfully commissioned with stored beam. This device is identified as the Intermediate Energy X-ray (IEX) undulator. The IEX undulator takes its name from the IEX beamline where it is installed. The IEX undulator is able to produce a variety of polarizations: linear vertical, linear horizontal, and right- or left-handed elliptical or circular. Ten pairs of poles, distributed quasi-periodically along the undulator length, are powered separately, allowing the field strength of the quasi-periodic poles to be adjusted. This adjustability allows the user to seek a balance between the suppression of the higher harmonics and the loss of flux in the fundamental that best suits the measurement being made. The IEX undulator has a 12.5-cm period and can achieve photon energies as low as 250 eV in horizontal polarization and 440 eV in vertical polarization. A description of the IEX undulator will be presented.

WEPSM11	The Intermediate-Energy X-ray (IEX) Undulator Commissioning Results	1070
	A. Xiao, M. Abliz, B. Deriy, M.S. Jaski, M.L. Smith, I. Vasserman, J.Z. Xu ANL, Argonne, USA
	Funding: Work supported by the U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. Strong beam perturbation from the intermediate-energy x-ray (IEX) undulator operation has been expected from the beginning. This paper describes our efforts including the initial magnet design, field measurements and compensation, special considerations of power supplies and the control system, and the final commissioning results with beam. Perturbations are well within the specified limits, and the IEX was made ready for user operation in less than six months.

Paper

Title

Page

Fast-Switching Variably Polarizing Undulator

1061

M.S. Jaski, R.J. Dejus, B. Deriy, E. Gluskin, E.R. Moog, I. Vasserman, J. Wang, A. Xiao
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
Development of a new fast-switching Electromagnetic Variably Polarizing Undulator (EMVPU) is underway at the Advanced Photon Source (APS). The EMVPU can produce x-rays with left- and right-handed circular polarizations and horizontal and vertical linear polarizations in the energy range 400-2000 eV. The undulator will be able to switch between left- and right-handed circular polarization at 10 Hz, fast enough to allow for magnetic circular dichroism studies that rely on lock-in amplifier techniques. The handedness switch will be accomplished by switching only the vertical component of the field while the horizontal component stays constant. Details of the EMVPU and its initial experimental test models are presented.

WEPSM09

An Electromagnetic Variably Polarizing Quasi-Periodic Undulator

1064

M.S. Jaski, M. Abliz, R.J. Dejus, B. Deriy, E. Gluskin, E.R. Moog, I. Vasserman, A. Xiao
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
An electromagnetic variably polarizing quasi-periodic undulator was installed in the Advanced Photon Source (APS) storage ring in April 2012 and has been successfully commissioned with stored beam. This device is identified as the Intermediate Energy X-ray (IEX) undulator. The IEX undulator takes its name from the IEX beamline where it is installed. The IEX undulator is able to produce a variety of polarizations: linear vertical, linear horizontal, and right- or left-handed elliptical or circular. Ten pairs of poles, distributed quasi-periodically along the undulator length, are powered separately, allowing the field strength of the quasi-periodic poles to be adjusted. This adjustability allows the user to seek a balance between the suppression of the higher harmonics and the loss of flux in the fundamental that best suits the measurement being made. The IEX undulator has a 12.5-cm period and can achieve photon energies as low as 250 eV in horizontal polarization and 440 eV in vertical polarization. A description of the IEX undulator will be presented.

WEPSM11

The Intermediate-Energy X-ray (IEX) Undulator Commissioning Results

1070

A. Xiao, M. Abliz, B. Deriy, M.S. Jaski, M.L. Smith, I. Vasserman, J.Z. Xu
ANL, Argonne, USA

Funding: Work supported by the U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Strong beam perturbation from the intermediate-energy x-ray (IEX) undulator operation has been expected from the beginning. This paper describes our efforts including the initial magnet design, field measurements and compensation, special considerations of power supplies and the control system, and the final commissioning results with beam. Perturbations are well within the specified limits, and the IEX was made ready for user operation in less than six months.