In its first try as a Sandia National Laboratories diagnostic tool, the third-biggest laser on earth, Z-Beamlet, confirmed that Sandia's Z machine - the most powerful laboratory producer of X-rays in the world -spherically compressed a simulated fusion pellet during a firing, or "shot," of the giant accelerator.

"The beam compressed the pellet by a factor of 2," says project leader John Porter, "and demonstrated an encouraging uniformity. Our results show we're moving in the right direction."

Uniform 3-D compression is an essential step in creating controlled nuclear fusion. It means that almost none of the X-ray energy delivered to the pellet squirted uselessly away. Weapons simulation work (the alternative to nuclear testing) conducted on supercomputers by Sandia for the US Department of Energy is expected to benefit from data from high-yield explosions, as should, further down the pike, energy production.

Until now, Z researchers had to be content with electronic images of smoother and smoother Z pinches - the tool of compression. The pinch - a vertical magnetic cylinder - with increasing smoothness impels ions of tungsten toward its vertical axis at a considerable fraction of the speed of light. But knowing that the tool is good and getting better isn't definite information about the pellet upon which the tool is operating. Only direct data is entirely convincing.

Z-Beamlet images the pellet in a kind of giant dental X-ray, says Porter. In a burst of energy only a fraction of a billionth of a second long, it takes a snapshot by creating a shadow on a piece of X-ray film placed behind the BB-sized pellet inside the central chamber of the firing Z machine. The shadow, like the picture taken of a tooth, accurately depicts what is going on in the "mouth" of Z.

Lawrence Livermore National Laboratory originally built the Beamlet laser to serve as the scientific prototype of the National Ignition Facility. The California lab decided to remove the laser to make room for those of the NIF.

The entire project to reassemble the recycled Livermore laser cost $12.875 million, took three years to complete, and required the talent and dedication of scores of individuals from Lawrence Livermore and Sandia, says Porter.