Obscura

15. Sandia Z



The Z pulsed power accelerator at Sandia National Laboratories, which began operating in September 1996, is the world’s most powerful and most efficient (15%) laboratory x-ray source. Z is really 36 separate pulsed power devices timed to fire simultaneously to within ten billionths of a second. It is not entirely a "new" accelerator, but a modified version of the 11-year-old PBFA II accelerator, which was used until the spring of 1996 for light ion fusion research. The four-month modification included a new power flow section and 36 new transmission lines, designed with sophisticated mechanical and electrical analysis codes.
The pulse that drives Z lasts less than ten billionths of a second--20,000 times faster than a lightning bolt--and yet carries 1,000 times the electrical current in a typical lightning bolt. But, in that brief instant, the accelerator produces an impressive amount of x-ray power, as much as 290 trillion watts (terawatts), and an x-ray energy of 1.9 million joules.


How are the x rays generated?
The Z accelerator uses huge electric currents (20 million amperes) to produce an ionized gas, or plasma, by vaporizing a spool-of-thread-sized array of 100 to 400 wires. The currents produce powerful magnetic fields that surround the plasma, pinching it on a vertical axis--hence the name "z pinch"--to densities and temperatures sufficient to generate an intense source of x rays.

posted by Cobb @ 10:02 AM