SSRL Celebrates 25 Years of Pioneering Insertion Devices
By Herman Winick
Twenty five years ago the first permanent
magnet undulator to be used for synchrotron radiation research was
implemented at SSRL, in collaboration with LBNL. A year earlier the
first electromagnet wiggler, designed by Jim Spencer, was implemented at
SSRL. These two pioneering insertion devices started the revolution in
synchrotron radiation sources and research.
gather in front of the first permanent undulator magnet display.
From left to right are Richard Boyce (ASD), John Yang (ESRD,
retired), Herman Winick (SSRL), Egon Hoyer (LBNL, retired), and
John Chin (LBNL, retired).
(Photo by Topher White)
Due to the success of these devices,
and similar experience at the Budker Institute in Novosibirsk, many
third generation synchrotron radiation sources (storage rings optimized
for such insertion devices rather than merely using radiation from the
ring bending magnets) were built starting in the late 1980ís. The latest
of these is the SPEAR3 storage ring at SLAC.
To mark this 25th anniversary, some of those who
contributed to the design, construction and characterization of the
spectrum for the first permanent magnet undulator gathered around the
magnet itself, which is on display on the SSRL experimental floor. The
concept for this magnet was the brainchild of Klaus Halbach of LBNL. The
mechanical design was done by LBNL engineers Egon Hoyer and John Chin,
controls for varying the gap and compensating the end fields was done by
John Yang, recently retired from SSRL. The spectrum from this device was
characterized by George Brown, Teresa Troxel, and Herman Winick of SSRL
along with Zahid Hussain and Eberhard Umbach at LBNL.