PAC2013 - List of Authors (Jaski, M.S.)

Paper	Title	Page
WEPSM06	Beam-Induced Heat Load Predictions and Measurements in the APS Superconducting Undulator	1055
	K.C. Harkay, L.E. Boon, M. Borland, Y.-C. Chae, R.J. Dejus, J.C. Dooling, C.L. Doose, L. Emery, Y. Ivanyushenkov, M.S. Jaski, M. Kasa, S.H. Kim, R. Kustom, V. Sajaev, Y. Shiroyanagi, X. Sun ANL, Argonne, USA L.E. Boon Purdue University, West Lafayette, Indiana, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The first prototype superconducting undulator (SCU0) was successfully installed and commissioned at the Advanced Photon Source (APS) and is delivering photons for user science. The cryosystem was designed to handle a beam-induced heat load of up to 40 W. Prior to operations, detailed predictions of this heat load were made, including that produced by resistive wall heating by the image current, geometric wakefields, synchrotron radiation, electron cloud, and beam losses. The dominant cw source is the resistive wall heat load. The heat load predictions for standard 100 mA user operation were benchmarked using thermal sensors that measure temperatures at various locations in the SCU0 cryostat and along the electron beam chamber. Thermal analysis using the predicted heat loads from the electron beam, using three independent methods, agrees well with the observed measurements.

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.

WEPSM10	Design of a 17.2-mm-Period Planar Undulator for the APS	1067
	E.R. Moog, M. Abliz, R.J. Dejus, J.H. Grimmer, M.S. Jaski ANL, Argonne, USA
	Funding: * Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357. The design process for a short-period planar undulator is described. This is a conventional planar design based on Nd-Fe-B magnets and vanadium permendur poles. The period length was driven by the users’ request for a high flux of photons at 23.7 keV, with minimal tuning range. A shorter period gives higher flux; 17.2 mm was the shortest value consistent with the gap limitations of the vacuum chamber and with reaching the desired photon energy. Details of the design, especially the various chamfers of edges of the magnet and pole, were examined more closely than has been the standard past practice in order to minimize the period length.

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.

THPAC06	Comparison of Simulations and Analytical Theory of Radiation Heating on the Advanced Photon Source Superconducting Undulator	1148
	L.E. Boon Purdue University, West Lafayette, Indiana, USA L.E. Boon, R.J. Dejus, K.C. Harkay, M.S. Jaski ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357 Synchrotron radiation can potentially introduce large heat loads on the beam chamber of the superconducting undulator (SCU) at the Advanced Photon Source (APS). With the photon absorber mask, a well-aligned centered beam in the upstream bending magnet allows only a small amount of radiation power, less than 1 W, to intercept the walls of the beam vacuum chamber in the cryostat assuming no photon scattering. But beams with vertical orbit errors, especially, can deposit much higher heat loads on the beam chamber, above 100 W. An analysis was carried out to calculate the power on the vacuum chamber when the beam has an orbit error through the upstream bending magnet. This paper presents these analytical results compared to simulations that were performed using a 3D photon tracking code, Synrad3d.

Paper

Title

Page

Beam-Induced Heat Load Predictions and Measurements in the APS Superconducting Undulator

1055

K.C. Harkay, L.E. Boon, M. Borland, Y.-C. Chae, R.J. Dejus, J.C. Dooling, C.L. Doose, L. Emery, Y. Ivanyushenkov, M.S. Jaski, M. Kasa, S.H. Kim, R. Kustom, V. Sajaev, Y. Shiroyanagi, X. Sun
ANL, Argonne, USA
L.E. Boon
Purdue University, West Lafayette, Indiana, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The first prototype superconducting undulator (SCU0) was successfully installed and commissioned at the Advanced Photon Source (APS) and is delivering photons for user science. The cryosystem was designed to handle a beam-induced heat load of up to 40 W. Prior to operations, detailed predictions of this heat load were made, including that produced by resistive wall heating by the image current, geometric wakefields, synchrotron radiation, electron cloud, and beam losses. The dominant cw source is the resistive wall heat load. The heat load predictions for standard 100 mA user operation were benchmarked using thermal sensors that measure temperatures at various locations in the SCU0 cryostat and along the electron beam chamber. Thermal analysis using the predicted heat loads from the electron beam, using three independent methods, agrees well with the observed measurements.

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.

WEPSM10

Design of a 17.2-mm-Period Planar Undulator for the APS

1067

E.R. Moog, M. Abliz, R.J. Dejus, J.H. Grimmer, M.S. Jaski
ANL, Argonne, USA

Funding: * Work supported by U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
The design process for a short-period planar undulator is described. This is a conventional planar design based on Nd-Fe-B magnets and vanadium permendur poles. The period length was driven by the users’ request for a high flux of photons at 23.7 keV, with minimal tuning range. A shorter period gives higher flux; 17.2 mm was the shortest value consistent with the gap limitations of the vacuum chamber and with reaching the desired photon energy. Details of the design, especially the various chamfers of edges of the magnet and pole, were examined more closely than has been the standard past practice in order to minimize the period length.

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.

THPAC06

Comparison of Simulations and Analytical Theory of Radiation Heating on the Advanced Photon Source Superconducting Undulator

1148

L.E. Boon
Purdue University, West Lafayette, Indiana, USA
L.E. Boon, R.J. Dejus, K.C. Harkay, M.S. Jaski
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
Synchrotron radiation can potentially introduce large heat loads on the beam chamber of the superconducting undulator (SCU) at the Advanced Photon Source (APS). With the photon absorber mask, a well-aligned centered beam in the upstream bending magnet allows only a small amount of radiation power, less than 1 W, to intercept the walls of the beam vacuum chamber in the cryostat assuming no photon scattering. But beams with vertical orbit errors, especially, can deposit much higher heat loads on the beam chamber, above 100 W. An analysis was carried out to calculate the power on the vacuum chamber when the beam has an orbit error through the upstream bending magnet. This paper presents these analytical results compared to simulations that were performed using a 3D photon tracking code, Synrad3d.