2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
American physicists have created an elementary particle accelerator that fits on a silicon chip several tens of microns in size. A device based on the technology of laser dielectric acceleration may in the future become the basis for compact and powerful accelerators that will find application in medicine, materials science, biotechnology, and many other fields. The research results are published in the journal Science.
In "conventional" accelerators, such as the Large Hadron Collider, elementary particles are accelerated using an electric field. But in order to obtain high-energy particles, accelerators must be very long, since a gradient of more than several tens of megaelectronvolts per meter cannot be provided - a breakdown will occur in the chamber. You can get around this problem by building a ring accelerator, but then you need powerful magnets to "rotate" the particles. In addition, a significant part of the energy “pumped” into the particles will be emitted due to synchrotron radiation. To minimize losses, ring accelerators have to be built on a huge scale.
To get around this problem, physicists are developing new methods for accelerating particles. These include, in particular, dielectric laser acceleration and laser-plasma acceleration, as well as acceleration based on terahertz pulses. For plasma acceleration methods, there is no limitation on the magnitude of the accelerating fields, and the acceleration rate for them can reach 100 gigaelectronvolts per meter, but this method is not devoid of drawbacks, one of the most important is the difficulty of creating a stable and effective laser-plasma acceleration at a distance exceeding several millimeters.
A team led by Jelena Vučković of the Stanford University Accelerator Laboratory decided to use dielectric laser acceleration. In this case, the particles are accelerated by an electric field that appears above a special transparent grooved structure, illuminated from below by a polarized laser beam.
Vuchkovich and his colleagues were able to assemble an integrated accelerator on a silicon chip, where electrons are accelerated by illumination with an infrared laser, for which silicon is transparent. The on-chip accelerator was able to add only 0.915 keV of energy to electrons, but at a distance of only 30 microns. In terms of meter, this gives a gradient of 30.5 megaelectronvolts per meter. In the future, scientists expect to "pack" a thousand of such accelerators into one device several centimeters in size and get a beam of particles with an energy of 1 megaelectronvolt at the output.
The authors of the study are already beginning to think about possible applications of the future accelerator, in particular, about its use for radiotherapy of cancer.
Previously, physicists dispersed particles using terahertz radiation and set a record for laser-plasma acceleration.