Study of Row Phase Dependent Skew Quadrupole Fields in Apple-II Type EPUs at the ALS

Conference · Fri May 07 04:00:00 EDT 2004

OSTI ID:840597

Steier, C ^[1]; Marks, S; Prestemon, Soren; Robin, David; Schlueter, Ross; Wolski, Andrzej

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1. LBNL Library

Since about 5 years, Apple-II type Elliptically Polarizing Undulators (EPU) have been used very successfully at the ALS to generate high brightness photon beams with arbitrary polarization. However, both EPUs installed so far cause significant changes of the vertical beamsize, especially when the row phase is changed to change the polarization of the photons emitted. Detailed measurements indicate this is caused by a row phase dependent skew quadrupole term in the EPUs. Magnetic measurements revealed the same effect for the third EPU to be installed later this year. All measurements to identify and quantify the effect with beam will be presented, as well as some results of magnetic bench measurements and numeric field simulations.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director. Office of Science. Office of High Energy Physics (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 840597
• Report Number(s): LBNL--57210; CBP Note - 664
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
BRIGHTNESS
PHOTON BEAMS
PHOTONS
POLARIZATION
QUADRUPOLES
WIGGLER MAGNETS