National Laboratories’ Z machine, the
world’s largest producer of X-rays, shook the ground for
several hundred yards in every direction for the first time since July
2006, when the 22-year-old facility was gutted to undergo a complete
refurbishment at a total project cost of $90 million.
Z has been overbooked in recent years with requests for
experiment time from national labs, universities, and the international
community. The facility is in demand because of Z’s
capability to subject materials to immense pressures, compress
spherical capsules to produce thermonuclear fusion reactions, fire
objects much faster than a rifle bullet, and produce data for models of
nuclear weapons effects — as well as, more arcanely, the
conditions surrounding black holes in space. Given its complex mission,
it was time for a more modern Z.
The improved version is capable of firing more often, at
higher energies, and with improved precision.
Sandia is a National Nuclear Security Administration
The new facility - optimized for both z-pinch and material
properties work - will increase the strength of its electrical pulse
from 18 million amps to an anticipated 26 million amps. The facility
also now offers improved control over the shape of its electrical pulse
for better reproducibility as it enters new experimental regimes.
A z-pinch is so named because the large current passing in the
vertical direction - the Z direction in cylindrical geometry - creates
a magnetic field that pinches together the ions of thin wires that
serve as electrical conductors until the current vaporizes them.
The 17.5-million-amp shot that signified the reopening of the
facility was used to test new system components. It concluded an
extensive facility outage during which the old pulsed power systems
were removed, and the tank structure that contains the accelerator was
extensively modified. New, more robust pulsed power components and
subsystems were installed. Utility infrastructure modifications were
made, and the accelerator subsystems were commissioned. Over the next
several months, Z will conduct more tests to verify, validate, and
optimize the performance and predictive models for the accelerator and
determine reliable operating points for science program operation, the
ultimate purpose for Z.