The latest analysis using a neutron beam provides insights into the properties of silicon crystals and the 'fifth force'.



An international research team has announced that it has analyzed silicon crystals used in semiconductors and other devices using a method that uses a neutron beam. It is said that this experiment deepened the knowledge about the characteristics of silicon crystals and the ' fifth force'.

Pendellösung interferometry probes the neutron charge radius, lattice dynamics, and fifth forces
https://www.science.org/doi/10.1126/science.abc2794



Neutron Beam More Accurate Probe Than X-ray, Could Also be Used to Find Physics''Fifth' Forces | NC State News
https://news.ncsu.edu/2021/09/neutron-beam-accurate-probe-fifth-forces/

Groundbreaking Technique Yields Important New Details on Silicon, Subatomic Particles and Possible'Fifth Force' | NIST
https://www.nist.gov/news-events/news/2021/09/groundbreaking-technique-yields-important-new-details-silicon-subatomic

An international research team led by the National Institute of Standards and Technology (NIST) analyzed silicon crystals using a neutron beam technique. X-rays are generally used for crystal structure analysis, but uncharged neutrons do not interact strongly with electrons in the crystal, making them more suitable for crystal measurement.

This time, the research team chose a rare method called 'Pendellösung interferometry'. When a neutron, which has both particle and wave properties, passes through a crystal, it produces two different standing waves: a standing wave along the atomic plane in the crystal and a standing wave between the atomic planes. When these standing waves interact, a pattern called Pendel oscillation is generated, and by analyzing this pattern, information on the force generated in the crystal can be obtained.

NIST scientist Michael Hoover said of the analysis using Pendel vibration: 'After preparing two guitars and making the same sound, one runs on a smooth road and the other on a bumpy road. It is explained by the expression 'run'. In this case, the same sound at the time of ringing is reflected on the road with a different structure, so analyzing the difference in sound gives insight into the bumps on the road. The researchers say that by improving the traditional Pendel fringe interferometry and rotating the silicon crystal after the first measurement to measure at different angles, the accuracy of the analysis has improved by about four times.


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The research team tested the values predicted by the X-ray scattering method , which is one of the methods for measuring the internal structure of a sample, by analysis using Pendel vibration. Although the accuracy of the X-ray scattering method is limited by the thermal vibration of atoms, this test suggests that the vibration of nuclei and electrons may not be as strict as previously assumed, so some X-ray scattering models are available. He said he underestimated the effects of thermal vibration.

In addition, according to this analysis, the range in which the 'fifth force' beyond the fundamental interaction may act was limited to 0.02 nanometers to 10 nanometers, which is narrower than previously assumed. The fifth force is an interaction other than the four fundamental interactions of electromagnetic force , weak force , strong force, and gravity in the natural world, and although it has been pointed out that it may exist since the 1970s, at the time of writing the article. Has not been confirmed. It is believed that the more limited scope of the Fifth Force will make it easier to discover in future research.

'The great thing about this work is not only its accuracy, but also the experimentation on the table,' said Albert Young, a professor of physics and co-author of the treatise at North Carolina State University. 'Making small, accurate measurements like this one can advance some of the most difficult questions about basic physics,' he said.

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