Z machine

The Z- machine is a test facility to perform material tests under very high temperatures and extreme pressures. She stands at the Sandia National Laboratories ( SNL) in Albuquerque / New Mexico / USA. It should also contribute to the development of a nuclear fusion power plant. In 2005, she was also the most powerful artificial X-ray source.

The name Z- machine is derived

  • From the vertical discharge direction of the x-rays (see Z axis)
  • From the vertical wires ( see below)

The Z- machine is an example of a Z- pinch (Z- squeezer ) arrangement for nuclear fusion.

Senior Fellow Thomas WL Sanford.

Construction

Z- machine is a cylinder with a diameter of 32 m and a height of 6 m and surrounded by electrical conductors 36 arranged radially in excess of 1 m diameter. In the middle of the vessel, which is filled with deionized water for isolation, there is a vacuum chamber with a 3 m diameter. In this, the so-called " Z-pinch ", a cylindrical array of 300 in the Z direction is extending, parallel tungsten wires the size of a yarn package ( with a height of about 20 cm)., The tungsten wire having a diameter of 10 microns, about 1 /10 of the thickness of a human hair. In the center of this wire cylinder sits the fusion capsule, a peppercorn large plastic ball that is filled with a mixture of deuterium and tritium. Thus, the atomic nuclei can fuse, the capsules must be compressed to a fraction of their original size and extremely heated. This can be achieved by the radiation pressure of a very intense X-ray radiation.

To generate these X-rays, an electric current of up to 20 million amperes is sent exactly the same through all 36 radial head for a very short period of time of less than 100 nanoseconds. The fine tungsten wires in the center evaporate thereby abruptly and turn into an extremely hot, ionized gas - a plasma. The current pulse then generates a strong magnetic field in the ( electrically conductive ) plasma, which is highly radially compressed and heated to the vertical axis ( the so-called pinch effect ). In turn, the plasma heats the wall material of the surrounding cylinder to a temperature of up to a few billion Kelvin. This means that this cylinder emits an intense X-ray pulse for a moment, with a peak power of 290 TW. Then makes this X-ray pulse on the fusion capsule, it is compressed by the radiation pressure to a fraction of their original size, while strongly heated. For a few nanoseconds here about 80 times the instantaneous power is implemented, which is consumed on the entire earth.

The electrical energy is provided by Marx generators.

Operation

2003 allowed the scientists to compress through the X-ray pulse of 120 TW fusion capsule to one sixth of its original diameter. The density of the deuterium nuclei thereby increased to two hundred times. Under these conditions, two cores of the heavy and superheavy hydrogen isotopes deuterium and tritium are so closely matched that they fuse to form a helium nucleus. The researchers estimate that their fusion free sat an energy of about 4 mJ.

In 2006 it was announced that a plasma with a temperature of over 2 billion Kelvin could be created, a temperature that is higher than that in the interior of stars ( only about 15 million Kelvin are in the core of the Sun, for example, reached). In addition, the energy of the emitted X-ray radiation was four times as great as it would have been expected in the supplied amount of kinetic energy. These results were previously although over a period of 14 months repeatedly confirmed experimentally, but is not yet fully explained.

The expansion to a larger " ZR- machine" is being planned. With it, one wants to generate X-ray pulses of up to 350 TW, higher densities and temperatures, and thus also gain much greater amounts of energy.

de