Particle accelerators could be incredibly useful for medicine – if they weren’t so huge. The SLAC accelerator, for example, is almost 2 mi (3.2 km) long, while CERN’s Large Hadron Collider (LHC) runs for a stunning 16.7 mi (27 km). Now, scientists at Stanford have managed to shrink the tech down to fit on a computer chip, which could lead to more precise cancer radiation therapies.
In regular accelerators, particles are beamed through vacuum tubes and accelerated to incredibly high speeds. The SLAC accelerator gives its particles a speed boost by irradiating them with microwaves, while the LHC uses superconducting electromagnets.
The machinery required to do that makes these systems very bulky, and hard to scale down for use in hospitals and smaller scientific facilities. In the past CERN has managed to create a smaller prototype that measures about 6.5 ft (2 m) long – and now a team from Stanford and SLAC have created an even smaller version that fits on a single silicon chip.
With the new design, electrons are beamed through a vacuum-sealed channel that’s 30 micrometers long and thinner than a human hair. Rather than microwaves or magnets, the Stanford device accelerates its particles using infrared light, which is funneled through silicon wires that poke through the walls in the channel. An infrared laser pulses 100,000 times a second, each time sending off a flurry of photons that strike the electrons at just the right angle to accelerate them forward.
In its current form, this particle accelerator-on-a-chip isn’t ready for practical use, but it does show that the concept works. For now, it only managed to give electrons an energy kick of 0.915 kilo-electronvolts (keV), which is about a thousand times smaller than is needed for research or medical applications.
By the end of the year, the team is shooting for 1 mega electronvolt (MeV), or about a thousand times more energy than the current form. Doing that is fairly straightforward – the researchers will duplicate the same stretch of channel 1,000 times, which should fit onto a chip measuring just 1 inch (2.5 cm) long.
So what can a particle accelerator-on-a-chip actually be used for? The researchers say that the first application could be more targeted cancer therapies. For example, a vacuum tube could be inserted into a patient with one end pointing straight towards a tumor. Electrons accelerated through this device could be funneled through this tube to strike the cancerous cells directly without hitting healthy ones nearby.
The research was published in the journal Science.
Source: Stanford
