The physicist Jens Stättelman develops accelerators at the GSI, the Helmholtz Center for Heavy Ion Research in Darmstadt. Here we find a particle accelerator with very special capabilities. We are specialists to accelerate heavy atoms, heavy ions.

As such, we are a very special lab. Most accelerators in the world just accelerate electrons and protons, and we can accelerate everything from protons to uranium. Researchers from all over the world use this diversity of particles in Darmstadt to investigate atoms and their cores, plasmas, cellular processes, and peculiar properties of materials.

They all require for their experiments various fast ions, for example, electrically charged atoms. To understand how a particle accelerator works, we have to first have a look at how atoms are constructed. The core comprises neutrons and positively charged protons.

This is surrounded by a shell of negatively charged electrons. The positive and negative charges of the atom cancel each other out. If we apply an external voltage, nothing happens. An applied electrical bias has no effect.

To accelerate an atom, we must first transform it into a positively charged ion. To do this, electrons must be stripped from the atom. The most easy way to do it is just to add heat. You heat it. For example, in something like a light bulb here, there is a filament made out of tungsten.

The current runs, the light bulb starts, gets very, very hot, and some of the tungsten atoms lose some electrons, and you get the steam out of tungsten ions. There are lost electrons in the electrons. We call that plasma. In theory, you could now apply a high voltage and extract some of these tungsten ions and have a very, very basic and simple ion source.

Behind TB, you see one of the ion sources of GSI. There we create this plasma much more effectively and from different elements. So from here, the ions start their journey through the accelerator complex. The path of the ions leads from the source to the linear accelerator. This accelerates the ions with the aid of an accelerating electrical bias

up to a maximum speed of 20% of the speed of light. Normally, you cannot accelerate ions with alternating voltage. You make them a little faster, and then you slow them down again. So what we use to, let's say, betray the ions that they think

they are accelerated by a constant voltage, we inject them in a chain of so-called drift tubes. In an electric field, the positive ions always move from the positive to the negative pole. In an alternating bias, they would simply move backward and forward.

To ensure the ions only move forward, we must trick them. Whenever the electric field is pointing in the wrong direction, the ions find themselves in a tube that shields them from the bias. Whenever the field points in the right direction, for example, the bias has the correct polarity, the ions receive a boost and move faster and faster.

However, to get anywhere near the speed of light, the accelerator must be many, many kilometers long. In such cases, the ions are directed from the linear accelerator into a ring accelerator. The ring accelerator is composed of magnets, which are capable of diverting the ions into a circle path.

For example, a given ion returns back to the same point after completing a tour of the ring, upon which it receives another boost. In this way, ions can be accelerated to speeds up to 90% of the speed of light. The entire process is driven from the central control room.

We are in the main control room of the GSI. From here, you set up the beams for the various experiments and the machines itself. So you have the sources, the uniluck, the SIS, heavy ion synchrotron, and the storage ring. We operate the machine 24 hours a day, 7 days a week. From here, you set up the beams to various experiments.

Yet the most exciting accelerator at the GSI is the FAIR facility, under construction since 2012. FAIR stands for Facility of Antiproton and Ion Research. We will be able to produce antiproton, this is antimatter, a completely new field of science. In addition, we still do science with heavy ions like we do today,

but we will have a factor of 100 to 1000 higher intensity compared to the present GSI accelerator. So it's like building the present GSI accelerator 100 to 1000 times. The use of antimatter, the large quantities of ions, and the higher energies at the FAIR facility

allow us to gain new insights into the structure of matter and the development of our universe.