Is the Rembrandt painting an original or a forgery? How do the active substances in a tissue sample react with the body cells? How do superconductors and other electronic components behave under different conditions? A synchrotron can help with these tricky questions: this is a huge particle accelerator facility that produces high-energy X-rays. This is directed to several experimental stations, known as beamlines, in order to expose material samples. In this way, scientists from research and industry can investigate a wide range of structures and processes at molecular level. The measurements can be used to optimize computer chips, identify the structures of viruses and develop new drugs in a targeted manner.

The catch is that synchrotron radiation sources always provide their extremely bright, pulsed X-ray beam at a defined strength and pulse frequency for a certain period of time, which is often not suitable for each of the sometimes 30 or even 40 connected experiments. The researchers at the stations therefore either have to work with filters and switches to modulate the beam. Or they have to wait for a certain beam time from the large-scale system that meets their needs. This can delay their project by weeks or even months. It is therefore much better to adjust the beam. “There are already good solutions for the energy and size of the beam,” reports Dr. Peter Gaal , one of the two founders of TXproducts. “But not for the time structure.”

The business idea: WaveGate is faster than the X-ray flash

This is exactly where TXproducts comes in with WaveGate, a small box that can be easily interposed in a beamline and enables the time structure of the X-ray beam to be adjusted to the respective experiment. The most important element of WaveGate are the lithium niobate crystals. These are piezoelectric crystals that are used as signal filters in every modern cell phone, but also in sensors for detecting viruses, for example. Such crystals generate an electrical voltage when they deform and, conversely, can be specifically deformed by applying an electrical voltage to them.

If the X-ray beam hits the surface of the crystal at a frequency of, for example, one pulse every 200 nanoseconds, the switch can emit a high-frequency electrical signal, which the crystal receives with tiny antenna-shaped structures that TXproducts has applied to its surface and converts into surface sound waves. The same type of sound waves are also generated by earthquakes. The switch triggers a kind of earthquake on the crystal, which changes the lattice structure of the crystal. With this altered surface structure, the X-ray beam is now reflected at a different angle. “We can use WaveGate to control the diffraction of the X-ray beam and thus select certain pulses of the beam and sort out the others,” explains the second TXproducts founder Daniel Schmidt. “For example, if I don’t need the pulse every 200 nanoseconds, but only one per millisecond.” To illustrate how fast the switch works, here’s a comparison: light travels a distance equivalent to seven times around the equator in one second. WaveGate can switch the X-ray beam on and off so quickly that the light only travels 30 meters in this time.

WaveGate is as variable as a Swiss army knife

Such ultra-precise selection can be extremely important for the highly complex experiments on synchrotrons. This is because too much radiation is harmful to many samples, which can only withstand a few pulses and otherwise disintegrate. “Some processes that I want to observe only last as long as a single pulse,” says Schmidt. “So I have to isolate a single one and can’t use any more.” WaveGate can therefore be used to dose both the amount of incident X-ray light and the frequency of its pulses at the beamline. And it is as variable as a Swiss army knife: the switch allows different settings and can be used for different experiments. This is where it differs from previous solutions. Conventional optics for adjusting the time structure are usually rigid and can therefore only be used for one type of experiment. They are also significantly more expensive than WaveGate.

WaveGate speeds up experiments and reduces costs

With WaveGate, many synchrotron experiments can be carried out considerably faster and more cost-effectively. “Work that used to take an hour and cost 1,000 euros may now be completed in half a minute for 10 euros,” says Peter Gaal. This not only benefits the researchers themselves, but also the operators of the synchrotron, as they can make better use of their beamlines. Gaal estimates that around 30 percent of experiments at synchrotrons benefit from this. Some even become possible in the first place.

Peter Gaal had the idea for WaveGate for some time. He is a scientist at the Leibniz Institute for Crystal Growth (IKZ) in Berlin, where he heads the X-ray optics working group. In principle, IKZ and DESY complement each other ideally: crystals are developed at IKZ that are needed for research at a synchrotron, such as the one DESY operates with PETRA III. Conversely, research at DESY provides answers to the question of how crystal growth can be improved. For this reason, the IKZ recently founded a JointLab with the Hamburg research center on the DESY campus in order to intensify the cooperation. A device like WaveGate can therefore act as a lubricant for the collaboration.

Partner search for joint progress

“However, alongside teaching and research, I initially didn’t have enough time to pursue the idea further,” recalls Gaal. “I needed a partner.” He found one in Daniel Schmidt. He was a student in Gaal’s working group, which he led as a deputy professor at the University of Hamburg. “Daniel had everything we needed for our project: He is a specialist in nanoresearch and high-resolution X-ray and laser technology – but above all, he has the necessary drive and ambition to really push something like this forward.”

Synergy effects with the DESY Start-up Office and beyourpilot

By being located in DESY’s Innovation Village, the two benefit from many synergy effects: For one thing, there are beamline researchers at DESY’s X-ray radiation source PETRA III who are just waiting for WaveGate to be ready to use it. “They will be our first customers, accompany our development and enable us to test the device without having to apply for beam time each time,” explains Daniel Schmidt. With regard to their foundation, the two scientists are supported by the  “DESY Start-up Office” and “beyourpilot” (Editor’s note: “beyourpilot” has been operating under the “Startup Port” brand since July 2023)  accompanied: The start-up consultant Dr. Christina Frehse is on hand to answer various questions. “It was actually the office that gave us the idea to found our start-up in the first place,” says Gaal. In addition, they can exchange ideas with other founders on campus and find suitable new employees.

Over 50 synchotrons worldwide could benefit from WaveGate

The need for WaveGate is obvious: there are more than 50 synchrotrons worldwide, each with several beamlines connected to it. The gain in flexibility and efficiency for their work should convince many operators and beamline researchers. Once the demonstrator is ready, its two developers plan to visit synchrotrons around the world to present their new technology. First sales are planned for 2023.

But that’s not all. Gaal and Schmidt have long been working on other switching devices. The next step is to add “PicoSwitch” to the enormous speed of WaveGate. Using the analogy of a beam of light that races around the earth seven times in one second, PicoSwitch switches the light on and off within the width of a pin. That is five to ten picoseconds (trillionths of a second). This will even enable researchers to study processes that take place faster than the length of one of the X-ray pulses itself – for example, how the molecules in the retina of an eye deform when light falls on them. There is also a great need for this in modern research with X-ray and laser radiation. The other product that TXproducts is planning is to be called “NanoGate”. It will work in a similar way to WaveGate, but can be used with other light spectra.

The six-figure price of the small devices should be seen in relative terms. Especially as, despite their modular design, each one will ultimately be unique: “We adapt each switching optic individually to the customer’s requirements,” says Daniel Schmidt. “For example, some need one that works in a vacuum – others don’t.” In modern high-tech research on synchrotrons, which cost billions to build and tens of millions to operate every year, such an amount is manageable – especially as it saves money with every subsequent experiment.

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