convert one element into another. This generally requires nuclear reactors or particle accelerators with kilometres of tunnels and huge superconducting magnets, but Ledingham and colleagues have used a laser to do the job. True, the laser is a huge one. Called Vulcan, and housed at the Rutherford Appleton Laboratory in Oxfordshire, it is the most powerful laser in the world and the size of a small hotel. But laser technology is progressing fast, and within 5 years lasers nearly as powerful as Vulcan could be small enough to fit on a table top. And this could bring the power of transmutation to the masses.
Ledingham and his colleagues have used Vulcan to add protons to gold nuclei to create mercury. But there is more to the new alchemy than turning one heavy metal into another. In a paper accepted by the Journal of Physics D: Applied Physics, the team holds out the tantalizing possibility of neutralizing dangerous radioactive waste. They used Vulcan to convert iodine-129, an isotope that remains active for millions of years, into iodine-128, which decays in minutes.
To carry out the transmutation, the researchers fired a picosecond laser pulse at a gold target. The intense energy of the laser beam blasts the gold atoms into a plasma of free nuclei and electrons, which then emit gamma rays as they pass through the rest of the target. These intense gamma rays collide with the atoms of iodine-129, shaking the nuclei so violently that a neutron is squeezed out.
Transmuting nuclear waste has long been considered an attractive way of dealing with the ugly by-products of nuclear power. Researchers in France, which uses nuclear energy to supply 80 per cent of its electricity, are obligated by law to investigate transmutation. The US also has an active research programme into this kind of alchemy, and the British government is considering whether to start one. Until now, the only options have been modified versions of nuclear reactors, in which neutrons released during fission collide with the unwanted isotopes and break them apart. But many anti-nuclear groups see this as a ploy for reviving nuclear power.