A team of DESY scientists has created a miniature double particle accelerator. It has the capablity to recycle some of the laser energy fed into it to boost the energy of the accelerated electrons a twice. The device makes use of narrowband terahertz radiation that lies between infrared and radio frequencies in the electromagnetic spectrum. And one accelerating tube is just 1.5 centimetres of length and 0.79 millimetres, is it’s area of cross section. Dongfang Zhang and Etal from the Center for Free-Electron laser Science (CFEL) at DESY displayed their experimental accelerator in the journal Physical Review X.
The small size of the device is due to the short wavelength of the terahertz radiation. “Terahertz-based accelerators have came up as promising candidates for future generation compact electron sources, as explained by Franz Kärtner. He is a Lead Scientist at DESY and also head of the CFEL group that made the device.
Scientists have successfully experimented with terahertz accelerators. It can enable features where large particle accelerators are just not feasible or important. “However, the technique is still not very advanced now, and the outcome of experimental terahertz accelerators was limited by the relatively small section of interaction between the terahertz pulse and the electrons.
For the new device, they took a longer pulse consisting of many cycles of terahertz waves. This multicycle pulse significantly broadens the interaction section with the particles. The scientists feed the multicycle terahertz pulse into a waveguide that is provided with a dielectric material. Within the waveguide, the rate of pulse is decreased.
A bunch of electrons is shot into the middle section of the waveguide just in time, so that it can travel along with the pulse. This idea increases the interaction region between the terahertz pulse and the electron bunch to a higher range as compared to some millimetres in earlier experiments.
