ALPHA-2: the sequel

While many experiments are methodically planning for intense works over the long shutdown, there is one experiment that is already working at full steam: ALPHA-2. Its final components arrived last month and will completely replace the previous ALPHA set-up. Unlike its predecessor, this next generation experiment has been specifically designed to measure the properties of antimatter.


The ALPHA team lower the new superconducting solenoid magnet into place.

The ALPHA collaboration is working at full speed to complete the ALPHA-2 set-up for mid-November – this will give them a few weeks of running before the AD shutdown on 17 December. “We really want to get some experience with this device this year so that, if we need to make any changes, we will have time during the long shutdown in which to make them,” says Jeffrey Hangst, ALPHA spokesperson. “Rather than starting the 2014 run in the commissioning stage, we will be up and running from the get go.”

The first piece to arrive was the ALPHA-2 cryostat from the TRIUMF laboratory in Canada. This cryostat will hold 16 LHC current leads to power the eight superconducting magnets in the new ALPHA-2 atom trap.  The leads will allow the ALPHA-2 set-up to use less liquid helium. “These leads were provided by CERN, and use special technology developed specifically for the LHC,” explains Jeffrey. “As a small collaboration, we could never have afforded this technology on our own.”

Meanwhile, the final piece of the ALPHA-2 puzzle – the superconducting solenoid magnet – was making its way from England. When it finally arrived on Wednesday 31 October, the ALPHA team had cleared the necessary space for it in the AD hall. This magnet, which was financed by a grant from the Carlsberg Foundation, provides a constant external field of about 1 Tesla for trapping the charged antiprotons and positrons that make up antihydrogen. 

The new solenoid magnet will surround but one of two regions of the experiment that will hold anti-particles. The first, a “catching” trap installed in June, will capture and store antiprotons. These will then be guided into the solenoid magnet to be made into antihydrogen, and to undergo both microwave and laser spectroscopy. These two regions will be connected by intermediate solenoid magnet coils, which were constructed by CERN earlier this year.

Though ALPHA-2 has only just arrived, discussions have already begun on a possible new experiment for the collaboration: ALPHA-3, which would investigate the properties of gravity. In order to make space for this possible expansion, a new platform was created over the experimental area for the ALPHA-2 electronics. Mind your heads, as this collaboration grows ever upwards…

ALPHA spokesperson Jeffrey Hangst gives a tour of the new ALPHA-2 set-up:

by Katarina Anthony