快猫短视频

MACHINES that can boost particles to the huge energies needed to reveal
supersymmetry may be easier to build than physicists thought.

Teams in the US, Europe and Japan are all working on rival designs for the
next big linear accelerator, in which beams are accelerated from either end and
collide in the middle
(快猫短视频, 31 March, p 6).
Till now, physicists
believed they would need a machine up to 25 kilometres long to get particles to
such high energies, but Pantaleo Raimondi and Andrei Seryi of the Stanford
Linear Accelerator Center in California believe they can shrink it.

The reason you need such large machines is because particles travelling at
slightly different speeds are bent differently by focusing magnets, an effect
called chromatic aberration. Designers usually deal with this by adding two
hexagonal magnetic fields called sextapoles鈥攐ne for vertical deflection
and one for horizontal鈥攖hat reverse the effect of the focus magnets. But
they have to position the sextapoles several hundred metres from the focus
magnets and each other to avoid another uncontrollable aberration.

However, Raimondi and Seryi found a way to put two sextapoles close to the
beam focus, one designed to remove vertical chromatic aberration, the other
designed to remove the second effect. 鈥淲e鈥檙e able to design a shorter system by
tuning all these different knobs,鈥� says Seryi. The design should reach energies
of 3 to 4 teraelectronvolts, far above the 0.5 TeV currently planned.