dual-pulse options have been developed
that provide the ability to drive a system
and monitor its response on timescales that
range from femtoseconds to microseconds.
The pace of progress is set to further
accelerate over the next few years. The first
X-ray laser, LCLS, delivered 120 pulses per
second, followed by SACLA in Japan at 60
per second. A new facility, the European-
XFEL based in Hamburg, Germany, turned
on in mid-2017, delivering pulses at 27,000
per second. And now an additional $1
billion is being invested by the DOE to
create the LCLS-II upgrade that will provide
up to a million pulses per second by 2020.
This will be transformative, allowing the
study of real-world systems that are simply
inaccessible today, including statistical
fluctuations and heterogeneous materials,
rather than idealized samples.
Normally when a field advances, the
performance of the system increases
incrementally, or sometimes by a factor of
10 or so. Here, the field had to cope with a
factor of a billion increase in capability-requiring a completely new approach to the
measurements, and innovation in almost all
aspects of the technology.
The incredible efforts in delivering this
novel X-ray source are thus only part of
the story. Precision science requires the
integration of new instrumentation and
The LCLS Coherent X-ray Imaging Experimental Station. Credit: Nathan Taylor, SLAC National Accelerator Laboratory
The LCLS facilities at SLAC National Accelerator Laboratory. Credit: SLAC National Acceleratory Laboratory