Pocket Sized Particle Accelerator Using THz Laser Pulses

A new pocket-sized particle accelerator has proven capable of projecting ultra-short electron beams with laser light at more than 99.99% of the speed of light.

Researchers, led by Lancaster and Manchester Universities, have had to slow down light to match the speed of the electrons using a specially designed metallic structure lined with ultrathin quartz layers.

They can now measure and manipulate particle bunches on time scales of less than 10 femtoseconds (1 femtosecond = 10-15 seconds). This will enable them to create strobe photographs of atomic motion.

This will lead to the development of high-energy, high-charge, high-quality THz-driven accelerators that are much cheaper and more compact. Cheap and powerful accelerator technology will have many new applications.

Particle accelerators are already used for particle physics, materials characterization, radiotherapy in hospitals (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.

Nature – Acceleration of relativistic beams using laser-generated terahertz pulses

Abstract
Particle accelerators driven by laser-generated terahertz (THz) pulses promise unprecedented control over the energy–time phase space of particle bunches compared with conventional radiofrequency technology. Here we demonstrate acceleration of a relativistic electron beam in a THz-driven linear accelerator. Narrowband THz pulses were tuned to the phase-velocity-matched operating frequency of a rectangular dielectric-lined waveguide for extended collinear interaction with 35 MeV, 60 pC electron bunches, imparting multicycle energy modulation to chirped (6 ps) bunches and injection phase-dependent energy gain (up to 10 keV) to subcycle (2 ps) bunches. These proof-of-principle results establish a route to whole-bunch linear acceleration of subpicosecond particle beams, directly applicable to scaled-up and multistaged concepts capable of preserving beam quality, thus marking a key milestone for future THz-driven acceleration of relativistic beams.

SOURCES- Lancaster and Manchester Universities, Nature
Written by Brian Wang, Nextbigfuture.com

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