The new development involving protons being accelerated to high energy states comes from scientists based at Sweden’s Chalmers University of Technology together with researchers from the University of Gothenburg. The aim was to pave the way for the construction of compact, cheaper equipment that uses protons.
The basis of the research was that modern high-powered lasers have the potential to reduce the size and cost of proton based equipment size and cost, since this application can accelerate particles over a much shorter distance compared with traditional accelerators. This is by reducing the distance required from kilometres to metres. The challenge faced by scientists is that laser generated proton beams are not energetic enough. The Swedish researchers have developed a new method which yields a doubling of the energy, paving the way for new devices that could be used for proton therapy.
Proton therapy is a type of particle therapy (radiotherapy) that uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. The medical basis is that charged particles damage the DNA of cells, ultimately killing them by stopping their reproduction. Applications to date indicate that proton therapy may cause fewer side effects compared with traditional radiation, since medical personnel can better control where the proton beams deposit their energy.
The new method is based on laser-solid interaction and it splits a laser into two less intense pulses (compared with current technology which uses one, more intense laser), and then fires these lasers at a sheet of foil from two different angles simultaneously. At the point the two pulses collide on the foil, this generates an electromagnetic field which heats the foil extremely efficiently. The end result is higher energy protons (a significant improvement of the proton spectra) based on the same initial laser energy as with current approaches.
Commenting on the development, Julien Ferri, a researcher at the Department of Physics at Chalmers said: “This has worked even better than we dared hope. The aim is to reach the energy levels that are actually used in proton therapy today. In the future it might then be possible to build more compact equipment, just a tenth of the current size, so that a normal hospital could be able to offer their patients proton therapy.”
The technology is detailed in the journal Nature Communications Physics, with the research paper titled “Enhanced target normal sheath acceleration using colliding laser pulses.”
