Normally, when you think of particle accelerators you think of very large structures that are made of lots of shiny metal, wires hanging from the ceiling and are normally located in remote locations. But imagine an accelerator that you could hold in your hand, or even just in-between your fingertips. This is exactly what scientists that work at Stanford University are trying to do.
If you’re not familiar with particle accelerators, then it’s basically a machine that accelerates particles. You didn’t see that one coming did you. The most common particles that are accelerated are electrons and protons. One of the most famous accelerators is the one at CERN, in Geneva: the Large Hadron Collider. At CERN, protons are accelerated and travel in a huge donut underground at nearly the speed of light. At CERN, they take two proton beams that are travelling in opposite directions and smash them together to produce ‘exotic’ particles, something I like to call a particle factory. To make sure the protons take a curved path, the LHC has huge magnets which influence the trajectory of the protons. This machine is absolutely huge, but what about small particle accelerators? How can scientists get a particle accelerator small enough to fit in our hands?
A physicist at Stanford University, Robert Byer, has made it his mission to make particle accelerators smaller for over 40 years. He believes that using lasers to transfer energy to electrons in a semiconductor chip is the way forward for smaller particle accelerators. In essence, the electrons are riding the ‘light wave’ and if they sit on the right place on the wave they will get pushed and accelerated. One of the hardest things about making a small particle accelerator is getting the electrons to accelerate down a very narrow channel. A Stanford graduate, Dyan Black, describes this as ‘It’s a little like threading an invisible needle.’ Byer and his team have a laboratory in the basement of the Spilker Engineering and Applied Sciences building at Stanford where they carry out experiments relating to miniature particle accelerators.
Byer says, ‘Early on, lasers were big – and they were inefficient, and they took all the power and water in your building to operate them. They got more and more efficient because we converted to semiconductor lasers and solid-state lasers – and all of a sudden, lasers then became everywhere.’ Lasers have numerous applications and accelerating electrons is one of them and could be very useful for medical applications.
A physicist at the SLAC National Accelerator Laboratory says, ‘One of the applications could be to take one of the fairly bulky, 10,000-pound accelerator devices that’s used in hospitals for radiation therapy and make that into something that’s chip-sized.’ Even bigger thoughts about the future include the possibility of inserting the chip-sized particle accelerator within the body of a patient in order to irradiate a tumour, so watch this space.
This article was adapted from an article for the National Public Radio.