How are new elements created? Mix together the ingredients, stir and then done? Unfortunately, it's not as easy as that. In order to make a new element, enormous amounts of energy are required and lots of experience. Sigurd Hofmann has worked for many years at the GSI, the Helmholtz Center for Heavy Ion Research in Darmstadt.

Our main work is to study new elements which we produce here at the GSI by fusion reactions at the accelerator. Most exciting is to find something new, to prepare the experiments and in our special case, these are the heavy elements and new elements.

We can do these experiments best here at GSI by using the beams which come from the linear accelerator.

To understand how new elements come into being, one has to first examine the makeup of atoms. An atom comprises uncharged neutrons and positively charged protons in its core and negatively charged electrons in the shell. The greater the number of protons and neutrons in the atomic core, the heavier the element. And the greater the number of protons in the core, the more they repel each other.

Eventually, no more protons can attach themselves. At this point, it is only possible with force. In order to bring about a new element, a lighter element is fired at another by means of an accelerator at a speed of 30,000 kilometers per second. This is sufficient to bring this projectile nucleus in close connection to the

target nucleus so that these two nuclei can melt and form the new element. To this end, the projectile is fired at its target from a 120 meter long linear accelerator.

Here we have our target wheel and this wheel is mounted inside this vacuum chamber and the beam is coming from the right side and it hits the wheel in this place. We have very high beam intensities and a fixed target would immediately melt in the beam and therefore we use this rotating wheel.

However, despite the large number of particles, two atomic cores combining to form a new element is a rare occurrence, happening only about once a week. The melting of these two nuclei, projectile and target, happens exactly in such

a foil here and still inside the foil which is only one micrometer thick. The new element escapes from this target material and goes into the direction of the separator. The new element is unstable and decays within fractions of a second in several stages leading to lighter and lighter elements.

In doing so, it emits alpha particles characteristic of the decay. Very sensitive detectors can measure the decay times and the energies of the emitted alpha particles exactly. The data are recorded in the measurement chamber, prepared for computer use and subsequently analyzed.

The signature that we measure here is so significant that we definitely can say this was a new element and we also get a lot of information from this one measured decay train. Six new elements have been discovered in this way, including elements such as Darmstadtium and Rhenium.

All of the elements discovered to date decay very rapidly. Nevertheless, researchers calculate that in the sea of instability, there must be an island of stability. According to some models, this could correspond to cores having between 120 and 126 protons.

In this range, peculiar physical effects come into play, making the elements once again more stable. On a large construction site next to the GSI, one can see the beginnings of the new generation of accelerators, FAIR, the Facility for Antiproton and Ion Research.

Because presently we can use only stable beams, which we find on Earth and which we accelerate with the UNILAC accelerator, but with more neutron-rich radioactive projectiles, we can come to much more neutron-rich isotopes of super-heavy elements where we expect much longer lifetimes.

The hunt for new elements continues and researchers in Darmstadt as well as in Russia and Japan are using new experimental techniques to edge ever closer to this island of stability.