Studying antimatter with laser precision

The next generation of antihydrogen trapping devices, ALPHA-2, is moving into CERN’s Antiproton Decelerator (AD) hall. This brand-new experiment will allow the ALPHA collaboration to conduct studies of antimatter with greater precision. ALPHA spokesperson Jeffrey Hangst was recently awarded a grant by the Carlsberg Foundation, which will be used to purchase equipment for the new experiment.


A 3-D view of the new magnet (in blue) and cryostat. The red lines show the paths of laser beams. LHC-type current leads for the superconducting magnets are visible on the top-right of the image.

The ALPHA collaboration has been working to trap and study antihydrogen since 2006. Using antiprotons provided by CERN’s Antiproton Decelerator (AD), ALPHA was the first experiment to trap antihydrogen and to hold it long enough to study its properties. “The new ALPHA-2 experiment will use integrated lasers to probe the trapped antihydrogen,” explains Jeffrey Hangst, ALPHA spokesperson. “The use of lasers for precision measurements will complement the microwave spectroscopic studies that we initiated in 2011.”

Unfortunately, laser spectroscopy cannot simply be incorporated into the existing set-up. “ALPHA was designed before we had even proved that trapping antimatter was possible,” says Hangst. “It is a very compact experiment – catching and mixing charged particles to make antihydrogen in a single unit. ALPHA-2 will split these two processes, allowing us to store antiprotons when the AD is off-line and making the installation of lasers possible.”

The Carlsberg Foundation grant will finance one of the largest parts of the new ALPHA-2 experiment: the superconducting solenoid magnet. While Carlsberg may be more widely known for its beers, its foundation has been supporting the sciences since the late 1800s. “In Denmark, the Carlsberg name is readily associated with the funding body,” says Hangst. “They have provided funding to postgraduates in a variety of disciplines and grants for experimental equipment. In the case of ALPHA-2, the Foundation just happens to be funding one of the largest parts of the experiment.”

With ALPHA-2 currently scheduled for installation within the next few months and results from the 2011 AD run under analysis, expect to hear more from the collaboration…

by Katarina Anthony