Status of the Development of Superconducting Undulators at the Advanced Photon Source

Novel correction procedure for compensating thermal contraction errors in the measurement of the magnetic field of superconducting undulator coils in a liquid helium cryostat

“…Modelling the contraction of the rod during the scan of the Hall probe position State-of-the-art SCUs used in accelerators have a horizontal cryostat that allows the alignment of undulator segments along the beam direction. Such cryostats are typically cooled down using conduction cooling with Gifford-McMahon cryocoolers (Casalbuoni et al, 2018) or by a thermosyphon principle including a tank of liquid helium (Ivanyushenkov et al, 2018). Opposite to this, the magnetic field characterization is often carried out in vertical cryostats hosting the magnet in a liquid helium bath.…”

“…In recent years, superconducting undulators (SCUs) have been successfully employed at synchrotron radiation sources (Casalbuoni et al, 2018;Ivanyushenkov et al, 2018). SCUs can offer a much higher on-axis undulator field than state-of-theart cryogenic permanent-magnet undulators with the same period and vacuum gap (Elleaume et al, 2000;Bahrdt & Gluskin, 2018).…”

Possibilities at the Polar beamline with APS-U

“…Fast polarization flipping between left and right circular as well as between horizontal and vertical linear polarization in the energy range from 2.7 to 27 keV will be possible with the new Superconducting Arbitrarily Polarizing Emitter (SCAPE) undulators which are currently being designed for the Polar beamline [2]. This will be achieved with the use of two in-line SCAPE undulators set to deliver horizontal and linear polarization (or circular left and right), respectively, and using small orbit bumps (30 urad) of the electron beam at frequencies up to 10 Hz to alternate polarization [9].…”

“…New Superconducting Arbitrarily Polarizing Emitter (SCAPE) undulators [2] which are being developed for the Polar beamline will make accessible especially the energy range above 14 keV for magnetic spectroscopy experiments. Energies above 14 keV are normally not reachable at conventional hard-x-ray beamlines using phase plates for polarization manipulation, and will enable investigation of magnetic properties of materials at the 5f L-and 4d K-edges using spectroscopic methods.…”

Comparison of Achievable Magnetic Fields with Superconducting and Cryogenic Permanent Magnet Undulators – A Comprehensive Study of Computed and Measured Values

“…The first superconducting undulator (SCU), called SCU0, to be installed in the APS storage ring was successfully commissioned in January 2013 [7]. As technology development proceeded, the SCU0 was followed by the SCU18#1 and the SCU18#2, both 18-mm-period undulators with a magnetic length of 1.1 m, in 2015 and 2016, respectively [8]. The SCU0 was replaced by the longer SCU18#2 after 3.5 years of continuous successful operation in the storage ring.…”