Computers, tablets and mobile phones are getting smaller and smaller. And ever more powerful at the same time. How does that work?

Spintronics is a young field of research in nanoelectronics. The results of spintronics could make our mobile phones and computers smaller and faster - with lower power consumption. Today's microelectronics are reaching their limits: At some point, it can't get any smaller. Spintronics, supported by nuclear neutron research, does not know this limit: the potential for miniaturisation here is immense.

Computer technology works primarily with electric current: when it flows, electrons are set in motion. However, they only do this as long as electricity is present. If the current is switched off, computer data is neither processed nor stored. Spintronics wants to change this. It also utilises the spin of an electron for data storage and processing. The spin is the angular momentum of the electron, caused by magnetism: it permanently rotates around itself, so to speak. The electron is either in the state of 2 "spin-up" and rotates clockwise. Or the 1 "spin-down" and rotates anti-clockwise. Spin-up corresponds to one, spin-down to zero: the basic arithmetic principle of every computer. Researchers have now discovered that this up and down state of the spins can be controlled. This means that spins can be coded, allowing data to be both stored and processed. The advantage: data processing with magnetism requires much less space than with electric current. Another advantage is that the electrons remain in the same spin state even without a current supply, meaning that data can be stored even without electricity. This "flipping" of spins into "up" or "down" requires much less energy than the conventional movement of electrons by electric current. Silicon chips with integrated spin transistors could work significantly faster and more energy-efficiently than current computer processors. Microchips and computers could be extremely miniaturised. Physicists are currently testing the magnetic control of materials that will make up next-generation mobile phone displays, televisions and computer monitors.

Storing huge amounts of data is what made the development of server centres and cloud services possible in the first place. Receiving films over the internet, using social media and even surfing the internet is only possible by storing large amounts of data. Research assumes that the storage limit will one day be reduced to the size of an atom using spintronics. There is still a long way to go. But the first spin components are already in use. A spintronic element is integrated into the read head of every modern computer's hard drive. The next step is to replace the magnetic hard drive with its rotating, sensitive parts. The storage capacity of hard disks based on individual electron spins would be a thousand times higher. More could be stored in much less space on magnetically freely addressable memories. In contrast to conventional silicon chips, the information would also not be lost in the event of a power failure.

How neutrons are used to research aeroplanes.

Neutrons are tiny, electrically neutral particles. They penetrate materials without damaging them - such as turbines, car engines or aeroplane walls. Researchers use neutron beams to investigate the influence of extreme stresses such as temperature, pressure or tension. The aim is to develop materials that are more durable, lighter and more cost-effective.

Aircraft of the future should fly faster, consume less fuel and do so without compromising safety standards. With the help of the Neutron research in the reactor, a step is now being taken in this direction. Airbus aeroplanes are still built with rivets today. The three segments of an A380 fuselage, for example, are joined together with 10,000 rivets. This is now set to change: Welding is to be used in future. A welded seam makes a lot of sense because it is more resistant and lighter than a connection with rivets. Welding would also be faster and cheaper. A welded aircraft would need smaller wings, less thrust from the engines and therefore less fuel. Until now, it has been technically difficult to check the weld seams for stability and density. This is extremely important for the safety of an aircraft. With neutron research, it is now possible to test whether the seams can withstand the extreme forces at an altitude of ten kilometres. This is because the neutron beam can be used to check and regulate the stress distribution in the weld seams. This examination makes it possible to look inside the weld seam and assess the quality of the weld seam based on its atomic structure.

Every person loses about a glass of water through their breath every day. Where to put this water in an aeroplane? An Airbus A380, for example, has room for over 800 passengers! Normally, the exhaled water vapour penetrates through the passenger cabin into the insulation of the aircraft. Several hundred kilograms of water collect, slosh back and forth or freeze on the cold aircraft wall. This increases the weight of the aircraft and thus the fuel costs. Mould can also form and short circuits can occur in the electronics. Scientists then simulated a transatlantic flight using a section of an aircraft wall and analysed it with neutrons. They wanted to know: How and where exactly does the water vapour freeze in the aircraft insulation? Does the water vapour first become liquid before it freezes? They used neutron radiography to illuminate the outer wall. The neutrons showed exactly: where is the water or ice during the climb, descent and ground phase? The researchers want to use the results to develop new water control systems for aeroplanes. There are also plans to develop new aircraft insulation, as this currently has to be completely replaced every two years.

Once upon a time there was the Big Bang ... And then? This question is to be answered by a huge particle accelerator. FAIR (Facility for Antiproton and Ion Research) is the name of the project near Darmstadt. Scientists call it the "universe in the laboratory". This is because the formation of our universe is to be investigated on a miniature scale and underground. "We are starting a few microseconds after the Big Bang," says Professor Karlheinz Langanke, Scientific Director of the GSI Helmholtz Centre for Heavy Ion Research. It is about nuclear physical processes in stars, about the development of stars and other cosmic objects. "Unclear astrophysics" is the name of this field of research, in which a new era is beginning with "FAIR". 3,000 scientists from 50 countries will use this facility. It is due to start in 2022. During operation, extremely small particles will be accelerated to 99 per cent of the speed of light. In the 1.1-kilometre-long circular accelerator, the particles then travel at around 300,000 kilometres per second and finally collide with a film of atoms. What exactly comes out of this? That is still completely open, says Professor Langanke.

The universe consists of five times more dark matter than visible matter. XENON1T is the most sensitive instrument for measuring dark matter in the world. "We assume that around one hundred thousand dark matter particles pass through the surface of a thumbnail every second," says Prof Manfred Lindner, Director at the Max Planck Institute for Nuclear Physics in Heidelberg. So far, no one has been able to detect them. XENON1T aims to change that. It is located in Italy in one of the largest underground laboratories in the world. 1,400 metres of rock protect against cosmic radiation. In addition, there are another 750 cubic metres of high-purity water around the core of the detector: 3.5 tonnes of the noble gas xenon at -95 degrees Celsius. "We need a large amount of detector material and extremely high radioactive purity," explains Prof Christian Weinheimer from the University of Münster. 248 light sensors register dark matter signals. They are so sensitive that they could even detect just one photon.

Nuclear physicists from Heidelberg have analysed around 200,000 galaxies in our universe. The scientists from the Max Planck Institute for Nuclear Physics in Heidelberg are part of a team of astronomers working on the GAMA (Galaxy And Mass Assembly) project. It is the most comprehensive energy measurement of the universe to date. The researchers have come to the conclusion that the universe produces only half the energy it did two billion years ago. This means: "In principle, the universe has already made itself comfortable on the sofa, put on a blanket and is about to doze off forever and ever," says Simon Driver. He is head of the GAMA science team. Almost all the energy in the universe was released with the Big Bang or immediately afterwards. Today, energy is only released when stars fuse atoms such as hydrogen or helium.

Why radiation is used for sterilisation

Humans are exposed to ionising radiation from natural sources on earth or in space, the intensity of which varies depending on the region. This particle radiation is also used for sterilisation. This is because this high-energy radiation eliminates pathogens, whether in cosmetic products or in medicine. In pharmaceuticals, semiconductor technology and the packaging industry: high-energy radiation is used everywhere for sterilisation. Sterilisation is used. No radioactivity is produced during sterilisation. Beta or gamma rays are usually used for sterilisation, which often has to be carried out through packaging.

It's not just our food that has to be germ-free: the material in which our food is packaged has to be too. This is why bottles, films and other packaging are sterilised with high-energy beta or gamma rays. Take yoghurt pots, for example: to prevent germs from getting into the yoghurt, it is sent to a sterilisation plant. Not every pot individually. Ionising radiation works through many layers of material. This means that entire pallets of yoghurt pots can be sterilised at the same time.

Food goes mouldy. To increase their shelf life or kill harmful microorganisms in food, they are irradiated. In Germany, for example, dried spices are treated in this way. This is because spices and herbs grown in the wild can contain bacteria and mould. When sterilised with superheated steam, the vitamin content, colours and aromas suffer. Sterilisation using beta or gamma rays preserves vitamins and flavours.

In the Medicine medical equipment or measuring instruments are irradiated. Catheters or artificial heart valves must also be sterile before they are inserted into the human body.

In the Cosmetics plant colour pigments are irradiated. They have a very high microbial load. This makes it possible to dispense with the use of preservatives.

Also Children's toys may contain microbes and pathogens when imported from other countries. Ionising radiation is also used here for sterilisation

NISRA and the search for a repository.

Scientists from many areas of research are working on further optimising the handling of radioactive waste, as well as exploring suitable disposal sites: Radioactive residues must be analysed and classified, rock formations geologically evaluated and long-term effects assessed. For the final disposal of radioactive waste, researchers are looking for so-called stable geological formations at depths of several hundred metres. The material is to be safely enclosed there. But how can the researchers precisely determine the materials for final disposal?

The method currently under development can be used to analyse more than just radioactive waste. Security authorities and industry can also benefit from determining the interior of high-density materials. The method is also suitable for quality control in the metal and electrical industries or for analysing cargo in shipping or airports without having to open it. Entire bridges could be inspected for cracks, fractures or other defects.

Radioactive waste products must be thoroughly analysed before being disposed of. Some of the old waste from the 1960s, 1970s and 1980s is encased in concrete. Scientists cannot simply look inside this waste using existing imaging methods. This is precisely where the research of the NISRA project should offer a solution: Because the development of new imaging methods would make it possible to precisely determine the materials in the radioactive waste.

How bacteria convert uranium and why this is revolutionary.

It was first discovered in 1987 in the sludge of the Potomac, a river on the Atlantic coast of the USA. The microorganism Geobacter. A "relative" of this bacterium is Geobacter Uraniireducens. One property of this microbe was spectacular for the scientists: it can break down or convert the heavy metal uranium. The radioactivity of uranium does not bother the bacterium. Just as humans convert oxygen into carbon dioxide, these bacteria "breathe" uranium(VI) into uranium(IV) and use the resulting energy for their metabolism. Geobacter Uraniireducens has fine hairs on the outside of its cell membrane. These form a kind of protective shield. These hairs are electrically conductive and can come into contact with the "food" uranium. By exchanging electrons, the microbe changes the uranium so that it becomes insoluble in water. This is known as "immobilisation". Although the uranium does not lose its radiation and still has to be disposed of, it no longer spreads in the environment. This is also interesting for possible clean-ups of decommissioned uranium mining sites.

Not only Geobacter uraniireducens can withstand radioactive radiation. Deinococcus radiodurans does too. Scientists discovered this microorganism in tinned meat from the army back in the 1950s. These had been irradiated for preservation - Deinococcus radiodurans survived. The microbe can withstand radiation doses of more than 10,000 grey. It is said that 15 grey is lethal for a human being. Although Deinococcus radiodurans cannot convert uranium directly like Geobacter uraniireducens, it can bind it via an intermediate step and thus stop its spread.

Researchers hope to produce tiny catalysts with the help of Geobacter and other bacteria. So-called nanocatalysts can activate molecules such as carbon dioxide or water and thus open up ways to utilise alternative energy sources such as ethanol and methanol or hydrogen. Carbon dioxide is a greenhouse gas and is produced during energy generation, through transport or in the steel industry. The chemical conversion of carbon dioxide is a very energy-intensive process. The uranium conversion of Geobacter could now be used to supply precisely this energy. In addition to obtaining an alternative energy source, the carbon dioxide would be neutralised. The Production of ammonia from nitrogen, nanocatalysts could help as energy suppliers. This is because around 1.4 per cent of global energy consumption is used for the production of ammonia alone. Ammonia is a basic chemical and is used in fertilisers, for example.

Travelling for 40 years: the Voyager 1 and 2 space probes

Since 1977 until eternity? The two Voyager probes have been travelling for over 38 years. Voyager 1 was launched on 5 September 1977, Voyager 2 on 20 August 1977 and each space probe weighed 825 kilograms at launch.

Battery power for 38 years. There are three radioisotope batteries on board each of the probes. The decay of plutonium produces heat, which is converted into electricity, similar to the processes in nuclear power plants. After 38 years, the batteries are still more than 56 per cent efficient.

"The great journey". The original task of the space probes was to explore Uranus, Saturn, Jupiter and Neptune. These planets are in a favourable constellation every 175 years. The four planets have never before been explored as extensively as by the two probes. The Voyager programme is also known as "The Great Voyage" and is the most successful space programme of all time.

Rapidly far away. The space probes race through space at a speed of around 61,000 kilometres per hour. That's around 1.4 million kilometres a day. Voyager 1 is over 20 billion kilometres away from Earth and is now flying through interstellar space. This makes it the furthest object from Earth that has ever been produced by human hands.

They fly and fly and fly. The probes had 90 kilograms of fuel with them at launch. Only around 55 kilograms have been used up. This is because the probes do not need fuel in empty space. If Voyager 2 were to fly to the nearest star, it would reach it in 40,000 years. It is called Ross 248.

Golden records in space. The Voyager Golden Records are gold-coated copper discs on board the space probes. They contain images and sounds of Earth - in case an extraterrestrial civilisation finds the records. The recordings include greetings in 55 different languages, sounds of wind, rain or animals. Even a kiss and pieces of music by Ludwig van Beethoven or Louis Armstrong. In extreme cases, the discs last 500 million years.

20 hours to earth. After completing its mission, Voyager 1 photographed the Earth in the Milky Way from a distance of six billion kilometres. The data took 20 hours from the space probe to arrive on Earth.

Shutdown by 2025. The computer on board Voyager has a working memory of 64 kilobytes, or 0.064 megabytes. In 1992, Voyager 1's on-board computer failed and the probe has been working with the backup computer ever since. By 2025, all eleven scientific devices in the space probes will gradually be switched off in order to save power and protect the devices.

Non-destructive material testing and age determination

The prophet's head by the sculptor Lorenzo Ghiberti (1378-1455) from 1442 was analysed using the Prompt Gamma Activation Analysis. The bronze sculpture is part of the Gate of Paradise opposite Santa Maria Del Fiore, the cathedral in Florence. The bronze gradually turned black. This layer needed to be removed. There were two methods to choose from: cleaning with a salt solution or with laser beams. Through the Neutron process the scientists realised that salt cleaning is more effective than lasers.

Together with the Federal Institute for Materials Research and Testing (BAM), the Germanisches Nationalmuseum in Nuremberg analysed 50 ink drawings by the painter Albrecht Dürer (1471-1528). It was not known whether they were really painted by Albrecht Dürer, whether he reworked them or whether others did? With the help of the Micro X-ray fluorescence analysis the researchers recognised: Albrecht Dürer used so-called iron gall ink. However, the inks in the drawings had different compositions. This enabled the scientists to recognise: Which pictures are by Dürer, which corrections did he make and which pictures are forgeries.

He was recovered frozen from the ice of the South Tyrolean Alps in 1991: "Ötzi". Never before had such an old and well-preserved mummy from the Neolithic Age been found. But how old is "Ötzi"? Researchers wanted to find out using the radiocarbon method, the C14 method. C14 is a naturally occurring, radioactive carbon isotope and is found in the tissue of every living organism. With death, the content in the body gradually decreases. The number of C14 isotopes in Ötzi's body revealed that Ötzi was over 5,000 years old. He lived around 3200 BC, 600 years before the first pyramid was built in Ancient Egypt.

An interview with Prof Dr Jörg Starflinger, Director of the Institute of Nuclear Energy and Energy Systems (IKE) at the University of Stuttgart about sunburn and orchid fans. Prof Starflinger investigates the effect of radiation on people and materials.

Germany has politically decided to phase out nuclear energy: What is the point of radiation protection?

In research, I speak of "radiation effects". We investigate this because people are always exposed to radiation. The question is: Where does radiation come from (source), where does it go (target) and what does it cause (effect)?

An example from everyday life?

Sunburn. Sunburn caused by UV radiation. The source is the sun, the target of the radiation is the human skin and the effect of the radiation is sunburn, in the worst case even skin cancer. The protection would be the sunshade.

Do you yourself also work outside the traditional areas of nuclear technology?

Yes, for example, we are currently supporting colleagues from the biology department in the investigation of mutations: We want to find out how plants or bacteria cope with low doses of radiation. This area of "radioecology" is one of the key areas of EU research. We also have a research project in the field of aviation and space travel: radiation is a permanent side effect in space. How does space radiation affect spaceships, materials and people in space, i.e. astronauts? This is important for future short-term missions in space, including the possible construction of a moon base or Mars base. 

Are you actually a nuclear engineer, but also work in the fields of biology and aerospace?

Yes, because it's no different than when we calculate gamma radiation or the activation of components in nuclear reactors, for example. It's about the method! I call this methodological expertise. We know how to calculate radiation fields. We know how to shield against radiation and so on. The question is: where can we utilise what we develop in nuclear technology in other areas? That's why I look to the future with confidence.

In which area are there still jobs for nuclear engineers today and in the future?

In addition to the upcoming dismantling of the systems, for example in medical device technology: I work with a colleague at the Marienhospital in Stuttgart. There are radiotherapy and diagnostic facilities there: we have a joint lecture and explain things to students: What is alpha, beta, gamma radiation, through to: How are the devices set up on site and what do they do? In other words, a brief introduction to the effects of radiation for all students who want to work in radiology (radiotherapy) or with tomography systems. It is also about improving radiotherapy planning. In medical technology, the methodological expertise of nuclear technology could be transferred.

"Winterising" means: Are you expecting a springtime of nuclear technology?

We will have completed the dismantling of the nuclear power plants in Germany at some point. However, I fear that the search for a final repository for the remaining highly radioactive material will take a very long time. As long as we have highly radioactive material above ground, we cannot neglect radiation protection or even do without it - we must retain the methodological expertise of nuclear technology!

How do you envisage maintaining expertise in nuclear technology?

Subjects with few students are called "orchid subjects". As is currently the case in my nuclear engineering lectures. If we see radiation protection as a social responsibility, even beyond dismantling, then nuclear technology needs to go into an orchid house - an orchid protection house. Because there are more and more voices saying that we no longer need nuclear technology. But we do need it and we need long-term programmes to maintain expertise in nuclear technology.