MAKE READY FOR THOR — Sandia National Laboratories technician Eric Breden
installs a transmission cable on the silver disk that is the new pulsed-power machine’s
central powerflow assembly. (Photo by Randy Montoya)
(January 5, 2015) Sophisticated features may influence eventual Z-machine rebuild
A new Sandia National Laboratories accelerator called Thor is expected to be 40 times more efficient than Sandia’s Z machine, the world’s largest and most powerful pulsed-power accelerator, in generating pressures to study materials under extreme conditions.
“Thor’s magnetic field will reach about one million atmospheres, about the pressures at Earth’s core,” said David Reisman, lead theoretical physicist of the project.
Though unable to match Z’s 5 million atmospheres, the completed Thor will be smaller — 2,000 rather than 10,000 square feet — and will be considerably more efficient due to design improvements that use hundreds of small capacitors instead of Z’s few large ones.
Remarkable structural transformation
This change resembles the transformation of computer architecture in which a single extremely powerful computer chip was replaced with many relatively simple chips working in unison, or to the evolution from several high-voltage vacuum tubes to computers powered by a much larger number of low-voltage solid-state switches.
Sandia National Laboratories technician Tommy Mulville installs a gas exhaust line for a
switch at Thor’s brick tower racks. In the background, beyond the intermediate support towers,
technician Eric Breden makes ready an electrical cable for insertion in the central power
flow assembly. (Photo by Randy Montoya)
A major benefit in efficiency is that while Z’s elephant-sized capacitors require large switches to shorten the machine’s electrical pulse from a microsecond to 100 nanoseconds, with its attendant greater impact, the small switches that service Thor’s capacitors discharge current in a 100-nanosecond pulse immediately, obviating energy losses inevitable when compressing a long pulse.