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JuSPARC – Lasers for Everyone!

A new family member for Jülich’s scientific infrastructure: JuSPARC is a milestone for information science and materials science at Forschungszentrum Jülich. All colleagues will soon be able to use the laser laboratory at the Peter Grünberg Institute – Electronic Properties (PGI-6). In the long run, JuSPARC will be established as a user facility. Eventually, particle acceleration will also be possible there.

Bang! In the cold vacuum of space, another rebel alliance spaceship is pulverised by turbo lasers with a burst of green energy. Science fiction scenes like this one from Star Wars are no longer necessary for Jülich physicist Prof. Markus Büscher from the Peter Grünberg Institute if he wants to see ultrafast lasers in action. He need only go to his laboratory where two top instruments are currently being set up. “Our Thales and Amphos lasers are on a peaceful mission, of course,” says Büscher with a smile. They will be in operation by the end of the year, generating X-rays for experiments. The function of these lasers will be to act as a radiation source at the Jülich Short-Pulsed Particle and Radiation Center (JuSPARC); they will help us to achieve a better understanding of ultrafast physical phenomena in materials.

Ein Thales-Mitarbeiter arbeitet am LaserThe JuSPARC Thales laser
Copyright: Thales

Within the next one to two years, Büscher and his team want to turn JuSPARC into a unique user facility. “The biggest challenge here is to operate the high-performance laser in daily continuous use with ever changing users – adjusting the lasers precisely for each researcher and the respective experiment in the shortest possible time.” No more than five to ten pulses – this is what the laser shots are called – can currently be produced in individual experiments in one day, and without changing users; or experiments run with high firing rates – but not in continuous operation. “We still have a lot of refinement to do to make 10 million pulses per second usable for everyone– and this is JuSPARC’s performance,” says the 56-year-old physicist.

Once this major task has been mastered, however, scientists at Forschungszentrum Jülich and other facilities will be able to use the laser almost continuously – as is the case with the JSC supercomputers. Jülich colleagues from various disciplines and institutes will thus benefit from the new laser laboratory soon.

Ein Thales-Mitarbeiter arbeitet am LaserFast and powerful: The Thales laser shoots a thousand times per second with a pulse energy of 1.4 terawatts.
Copyright: Thales

From biology to energy research

Physicists expect completely new findings for information technology from the lasers, particularly regarding the question of how spins – i.e. the intrinsic angular momentum of particles – behave in, for instance, semiconductors and certain metals. "For example, it is possible to discover which materials are suitable for faster and more energy-efficient data storage,” explains Büscher. The high shot rate of the lasers is an advantage here, with which spins can be frequently switched between states – a bit like tiny switches. “This is similar to use in hard drives.”
Lasers are also useful for applications in the Internet of Things – for developing thermoelectric materials, for example, which produce electricity from heat or other sources in the natural environment to measure body or environmental factors with tiny sensors. “Of course, it takes time for the corresponding devices to be launched on the market. But basic research is simply essential," says Büscher.

According to Büscher, JuSPARC can also be interesting for many other fields of research – for example for colleagues from structural biology, solid-state research, and energy research. Among other things, lasers could provide a better understanding of elementary processes in solar and fuel cells and thus help to develop improved materials.

As with a lot of infrastructure at Forschungszentrum Jülich, JuSPARC and the associated expertise at Jülich will be made available to scientists from other institutions. The fact that JuSPARC is not just relevant for the scientific campus at Forschungszentrum Jülich was confirmed by a recent review conducted within the context of the Helmholtz Association’s programme-oriented funding. The international reviewers explicitly stressed the importance of JuSPARC. A total of € 5 million was made available from Forschungszentrum Jülich’s Structural and Development Fund (STEF) to establish the laser laboratory. This has been supplemented by € 3.2 million in funding from the Helmholtz Association’ ATHENA project.

sketch of how JuSPARC's Thales laser worksHow does JuSPARC's Thales laser work? The laser fires highly compressed light pulses onto a material. Some of the light in it flips spins on an atomic level. The other part of the light is deflected by mirrors and first strikes a noble gas. In it, it is converted into harder radiation such as X-ray light. This radiation then also hits the material to be examined and ends up in a detector - a kind of special camera. "Now you have to imagine the whole thing with insanely fast constant fire", explains Markus Büscher. "This allows us not only to take individual snapshots, but also to observe the dynamic processes of spins."
Copyright: Adrian Sonnberger

Next stop: particle accelerator!

With the scope of ATHENA funding and in cooperation with the Nuclear Physics Institute (IKP), Büscher and his colleagues from PGI-6 intend to develop the Thales laser into a laser-based particle accelerator in the coming years. “We would then have an accelerator that would fit onto two laboratory tables and which could catapult the particles almost to the speed of light within just a few millimetres,” says the physicist, outlining the fascination of this idea. The laser could thus generate even stronger particle radiation – and open up completely new questions.

“Our long-term goal with the laser particle accelerator is a user facility,” Büscher emphasizes. However, he knows there is still a long and strenuous way to go. The researchers first have some tough nuts to crack to develop the lasers required for such continuous operation together with the manufacturers. “But we are taking things step by step. The first major hurdle will be to make JuSPARC – even without accelerated electrons – fit for daily use on campus,” says Büscher, who is already looking forward to the first shot with the new lasers.

JuSPARC: a comparison of two turbo lasers

The Thales Laser

Pulses per second:1,000
Duration of pulse: 30 femtoseconds (approx. one hundredth of a trillionth of a second)
Light output per pulse:1.4 terawatts (for comparison: the output of all power plants worldwide is 10 terawatts)
Average power (light energy per second): 40 watts
Produces:extreme UV light and soft X-rays
Principle:radiation hits material first and then a CCD detector

The Amphos Laser

Pulses per second:10,000,000
Duration of pulse: 100 femtoseconds
Light output per pulse:500 megawatts
Average power (light energy per second): 500 watts
Produces:extreme UV light
Principle: radiation hits material, electrons are knocked out and strike an electron spectrometer



Hanno Schiffer

This article is taken from INTERN, the in-house magazine of Forschungszentrum Jülich, Issue 3/2018.


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