Making the invisible visible

6 November 2017

It is the first exhibition in the School of Seeing on the Gutenberg campus that is concerned with the natural sciences. Through its ZoomIn—Making the Invisible Visible show, the Precision Physics, Fundamental Interactions and Structure of Matter Cluster of Excellence, or PRISMA for short, is providing insight into its many and varied branches of research. Multimedia exhibits show how modern technology is used to gain an in-depth view of the world’s tool box.

"Fundamental research in general and physics in particular are widely seen as somewhat abstract disciplines," says Professor Hartmut Wittig. "We want to prove the opposite. Our ZoomIn exhibition shows how we manage to visualize even the smallest structures in our universe." Wittig's colleague, Professor Matthias Neubert, continues: "We want to share our exciting research with the public." The PRISMA Cluster of Excellence does regularly do so, for example in its very prominent lecture series on physics in the Mainz State Theater or its representation at the annual Science Festival held in the Mainz city center. "Time and again, I am surprised by the general public's fascination for our subject."

The new ZoomIn exhibition with its multimedia elements gives a further impetus to this fascination. The two coordinators of the PRISMA Cluster of Excellence have come to officially open the exhibition in the School of Seeing on the campus of Johannes Gutenberg University Mainz (JGU).

A virtual reality headset that takes you on a polar expedition

"This is the first exhibition in the School of Seeing that focuses on the natural sciences," emphasizes Professor Elisabeth Oy-Marra. The professor of Art History and chairperson of the Executive Committee of the School of Seeing freely admits: "We humanities scholars understand only little about PRISMA, although we are constantly hearing the name." The exhibition provides an opportunity to change this. After all, the School of Seeing is located directly at the center of the Gutenberg campus. This is where those studying and working in the disciplines of the humanities, cultural studies, and the social sciences come and go.

The world of physics starts with the Big Bang, as does the exhibition. Short texts introduce the subject while avoiding, wherever possible, the use of technical jargon and provide information on the structure of matter:  "Following what was a fleeting explosive expansion, a dense plasma made up of elementary particles was generated ..." The texts also tell us about the building blocks of our world: "Our Standard Model of elementary particles provides for twelve particles of matter and four types of so-called energy particles." Then come the displays that demonstrate how the physicists at PRISMA detect these tiny components of the universe and which devices they use to solve the puzzles of modern physics.

The ZoomIn exhibition presents a number of multimedia exhibits. Also present at the opening are scientists who are there to talk about their research. Dr. Peter Peiffer, for example, is part of a team at the IceCube detector at the South Pole that is working on tracing the activity of the neutrino. For this purpose, over 5,000 light detectors have been buried in a cubic kilometer of ice there. The exhibition shows a virtual reality headset with which visitors can obtain an initial impression of what IceCube is like.

3D animation for ATLAS

Peiffer has also brought along an example of a new sensor that is to be used within this gigantic ice cube. "Our previous modules only measured the light in the visible spectrum. With this new generation of sensors, we can also detect UV light and absorb short-wave light. This can provide for massive augmentation of the results we obtain.”

Friedemann Neuhaus and Andreas Düdder are members of Professor Matthias Schott's research team. They are presenting a panel measuring two square meters, which is to be used in the ATLAS experiment. It will one day form part of an experiment in the Large Hadron Collider (LHC) at CERN, the world's largest particle accelerator. "The panel is extremely flat," Düdder explains. The maximum deviation permitted is 0.11 millimeters. "In Mainz we specialize in building such flat panels." Each of the 32 detector modules requires five of them. "Two are being produced in Munich and we will be supplying three," the physicist says.

The panels will become part of a new detector system that will allow even more accurate measurements of electrons. Neuhaus has created a 3D animation film that takes the viewer into the LHC and demonstrates the ATLAS experiment. The short film is running on a large screen in the background.

The laser spectroscopy display is a little more modest. An atom is shown in diagram form, with electrons circling around a nucleus in various orbits. A brightly lit line of dots represents a laser beam hitting an electron. This is an interactive display, and it is possible to change the color of the beam. If the visitor selects the right shade, an electron will jump out by one orbit.

Tours, lectures, events

This display is intended to illustrate the research being undertaken by Professor Randolf Pohl and his team. "The orbits of the particles are not as regular as in this model," the physicist explains. "Sometimes they even pass through the nucleus." With the help of these circulating particles, the researchers can draw conclusions about the structure of the atomic nucleus. Pohl sketches his experiments. There are protons and muons, which are "the fat brothers of electrons."  Some of their measurements have revealed that the radii of protons can deviate by up to four percent. "It may not sound like much," Pohl admits. However, it was enough to get his research onto the title pages of international journals.

Professor Niklaus Berger is part of the team that designed the ZoomIn exhibition. He himself works on the Mu3e project, the topic of another display. Mu3e makes use of high-tech chips to measure particles. "These are basically pixel chips, like those in a camera," Berger explains. They have to be very thin and able to respond extremely quickly to being hit by particles. The exhibition shows such a chip under a magnifying glass.

It is impossible to fit the whole of what is being done in the PRISMA Cluster of Excellence into a single exhibition room. Therefore the researchers selected various highlights of their work and decided for a spotlight on detecting dark matter and neutrinos, also known as the ghost particles of the universe, as well as on the new MESA electron accelerator which is taking shape at Mainz University. During the next couple of weeks, a series of guided tours and lectures will accompany the exhibition. All of these will provide additional information on the fascinating research being undertaken within PRISMA, in a discipline that renders visible what the naked human eye could never see.