SoylentNews is people
SoylentNews
from the is-that-a-particle-accelerator-in-your-pocket? dept.
Phys.org has the story on new research demonstrating an extremely small particle accelerator that uses lasers to generate terahertz frequency pulses of light to accelerate electrons.
Scientists have successfully developed a pocket-sized particle accelerator capable of projecting ultra-short electron beams with laser light at more than 99.99% of the speed of light.
To achieve this result, the researchers have had to slow down light to match the speed of the electrons using a specially designed metallic structure lined with quartz layers thinner than a human hair.
This huge leap forward simultaneously offers the ability to both measure and manipulate particle bunches on time scales of less than 10 femtoseconds (0.000 000 000 000 01 seconds, or the time is takes light to travel 1/100th of a millimeter). This will enable them to create strobe photographs of atomic motion.
Particle accelerators are widespread with applications in basic research in particle physics, materials characterisation, radiotherapy in hospitals, where they are used to treat cancer patients, radioisotope production for medical imaging, and security screening of cargo. The basic technology (radio-frequency oscillators) underpinning these machines however, was developed for radar during the Second World War.
In new research published today in Nature Photonics, a collaborative team of academics show that their unique solution is to use lasers to generate terahertz frequency pulses of light. Terahertz is a region of the electromagnetic spectrum between infrared (used in TV remotes) and microwave (used in microwave ovens). Laser-generated THz radiation exists in the ideal millimeter-scale wavelength regime, making structure fabrication simpler but most importantly providing the half-cycle lengths that are well suited for acceleration of whole electron bunches with high levels of charge.
In addition to applications such as radiotherapy and imaging, in the long run the researchers feel this technology could potentially be used to replace miles-long particle accelerators in use today with devices only meters in length.
Journal Reference
Hibberd, M.T., Healy, A.L., Lake, D.S. et al. Acceleration of relativistic beams using laser-generated terahertz pulses. Nat. Photonics (2020). DOI: 10.1038/s41566-020-0674-1
(Score: 4, Insightful) by Immerman on Wednesday August 12 2020, @03:04PM (1 child)
Electric _fields_ propagate at light speed, electric charges rarely get anywhere close.
I think you might be misunderstanding your link, which appears (my relativistic electromagnetism is 20-years rusty) to be talking about electromagnetism's invariance under Lorentz transformation - a.k.a. you should see the same behavior of a system no matter how fast you're passing it. Which is a real problem with a naive understanding of electromagnetism.
For example, if I had a long charged rod containing 1 Coloumb of charge per meter, and a separate electrostatic charge held stationary next to it, the charge would be subjected to an electrostatic field, but NOT a magnetic one since there is no current flow in the rod.
However, if I were to fly along the length of the rod at a rate of even just 1m/s, I would then see a 1amp (=1 Coloumb per second) current flow in the rod in the opposite direction, which would mean that from my perspective the charge *would* be subjected to a magnetic field from the rod, and thus would be expected accelerate differently when released. Which is obviously a problem - the velocity of the observer should not have any effect on the behavior of the system.
(Score: 0) by Anonymous Coward on Wednesday August 12 2020, @05:36PM
Are you sure that is a problem? [sciencemag.org]