Manufacturing Bits: Nov. 3

Zeptosecond measurements; attoseconds; laser funding.


Zeptosecond measurements
A group of researchers have set a new world’s record for the shortest timespan measurement.

DESY, Fritz-Haber-Institute and Goethe University Frankfurt have measured how long it takes for a photon to cross a hydrogen molecule. The result? About 247 zeptoseconds. A zeptosecond is a trillionth of a billionth of a second (10-21 seconds).

This is said to be the shortest timespan that has been measured to date.

Researchers carried out the time measurement on a hydrogen molecule. The molecule was irradiated with X-rays from the synchrotron lightsource PETRA III at DESY. Measuring 2.3-km, PETRA III is one of the world’s brightest storage-ring-based X-ray radiation sources.

In the lab, researchers set the energy of the X-rays. A photon was able to eject both electrons out of a hydrogen molecule. “The photon behaved here much like a flat pebble that is skimmed twice across the water: when a wave trough meets a wave crest, the waves of the first and second water contact cancel each other, resulting in what is called an interference pattern,” according to researchers.

Researchers measured the interference pattern of the first ejected electron using a COLTRIMS reaction microscope. COLTRIMS (cold target recoil ion momentum spectroscopy) is an imaging technique that measures the complete fragmentation of a sample.

“Since we knew the spatial orientation of the hydrogen molecule, we used the interference of the two electron waves to precisely calculate when the photon reached the first and when it reached the second hydrogen atom,” said Sven Grundmann, a researcher. “And this is up to 247 zeptoseconds, depending on how far apart in the molecule the two atoms were from the perspective of light.”

Reinhard Dörner, a professor at Goethe University, added: “We observed for the first time that the electron shell in a molecule does not react to light everywhere at the same time. The time delay occurs because information within the molecule only spreads at the speed of light. With this finding we have extended our COLTRIMS technology to another application.”

Attosecond spectroscopy
ETH Zurich has measured the electron movements in liquid at ultra-slow speeds.

Researchers have succeeded in studying the first few dozen attoseconds of this process. An attosecond is a millionth of a millionth of a millionth of a second.

The new measurements took place in a high vacuum system. Researchers injected a 25-micrometer-thin water microjet into a measuring chamber. This allowed them to measure the electrons that are emitted from water molecules in liquid.

“Electron movements are the key events in chemical reactions. That’s why it’s so important to measure them on a high-resolution time scale,” said Hans Jakob Wörner, a professor at the Laboratory of Physical Chemistry at ETH Zurich. “The step from measurements in gases to measurements in liquids is of particular importance, because most chemical reactions – especially the ones that are biochemically interesting – take place in liquids.”

“In these first few dozen attoseconds of a reaction, you can already observe how electrons shift within molecules,” said Wörner. “Later, in the course of about 10,000 attoseconds or 10 femtoseconds, chemical reactions result in movements of atoms up to and including the breaking of chemical bonds.”

Laser funding
The U.S. Department of Energy (DOE) has provided new funding for an initiative to advance the development of high-intensity laser research in the United States.

The initiative, called LaserNetUS, was originally formed in 2018. This initiative includes ten high-intensity laser facilities at national laboratories and universities in the U.S. and Canada. Lasers are used in various applications, such as defense, medicine, science and others.

Originally, the goal of this program was to help restore the U.S.’s once-dominant position in high-intensity laser research. In recent times, though, Europe and Asia have taken the lead in the arena.

That’s still the case. Under the new plan, the DOE is allocating $18 million in new funds for LaserNetUS over the next three years.

Today, a new laser revolution is underway. The industry is developing petawatt-class lasers (1 petawatt: 1 million billion watts). These systems can deliver 100 times the world’s total power consumption in less than one-trillionth of a second, according to the SLAC National Accelerator Laboratory.

These systems can accelerate and collide intense beams of elementary particles, drive nuclear reactions, heat matter to conditions found in stars, or even create matter out of an empty vacuum, according to SLAC.

The LaserNetUS institutions include Colorado State University, Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, SLAC, The Ohio State University, University of Michigan, University of Nebraska-Lincoln, Institut National de la Recherche Scientifique, University of Rochester and University of Texas at Austin.

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