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Lopez, M. R.

Publications and source records attributed to Lopez, M. R..

X-ray power and yield measurements at the refurbished Z machine

Advancements have been made in the diagnostic techniques to measure accurately the total radiated x-ray yield and power from z-pinch implosion experiments at the Z machine with high accuracy. The Z machine is capable of outputting 2 MJ and 330 TW of x-ray yield and power, and accurately measuring these quantities is imperative. We will describe work over the past several years which include the development of new diagnostics, improvements to existing diagnostics, and implementation of automated data analysis routines. A set of experiments on the Z machine were conducted in which the load and machine configuration were held constant. During this shot series, it was observed that the total z-pinch x-ray emission power determined from the two common techniques for inferring the x-ray power, a Kimfol filtered x-ray diode diagnostic and the total power and energy diagnostic, gave 449 TW and 323 TW, respectively. Our analysis shows the latter to be the more accurate interpretation. More broadly, the comparison demonstrates the necessity to consider spectral response and field of view when inferring x-ray powers from z-pinch sources.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

K-shell emission trends from 60 to 130 cm/μs stainless steel implosions

Recent experiments at the 20 MA Z Accelerator have demonstrated, for the first time, implosion velocities up to 110–130 cm/μs in imploding stainless steel wire arrays. These velocities, the largest inferred in a magnetically driven implosion, lead to ion densities of 2 × 10{sup 20} cm{sup −3} with electron temperatures of ∼5 keV. These plasma conditions have resulted in significant increases in the K-shell radiated output of 5–10 keV photons, radiating powers of >30 TW and yields >80 kJ, making it the brightest laboratory x-ray source in this spectral region. These values represent a doubling of the peak power and a 30% increase in the yield relative to previous studies. The experiments also included wire arrays with slower implosions, which were observed to have lower temperatures and reduced K-shell output. These colder pinches, however, radiated 260 TW in the soft x-ray region, making them one of the brightest soft x-ray sources available.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗