The new deceleration ring ELENA will slow down antimatter particles further than ever to improve the efficiency of experiments studying antimatter. (Image: Maximilien Brice/CERN)
On 2 August, the first 5.3 MeV antiproton beam coming from CERN’s Antiproton Decelerator (AD) circulated in the Extra Low ENergy Antiproton (ELENA) decelerating ring.
ELENA is the new decelerator for antimatter experiments. It has a circumference of just 30 meters and will be connected to the AD experiments to increase the number of antiprotons available to several antimatter experiments. The slower the antiprotons (i.e. the less energy they have), the easier it is for the AD’s antimatter experiments to study or manipulate them. However, the AD decelerator can reliably only slow antiprotons down to 5.3 MeV, the lowest possible energy for a machine of this size. ELENA will reduce this energy by 50 times, to just 0.1 MeV. In addition, the density of the beams will be improved. The number of antiprotons that can be trapped will be increased by a factor of 10 to 100. The new decelerator will also enable several experiments to receive antiproton beams simultaneously, opening up the possibility for additional experiments, such as GBAR.
This is not the first time that a beam has circulated in ELENA. The first tests began last November, but this is the first time that antiprotons, the particle type this machine has been conceived for, have been injected. The beam of antiprotons has been successfully injected and it has been observed circulating for a few milliseconds (that is, a few thousand turns of the machine).
The commissioning of the machine will continue over the next coming months with setting-up of several systems such as the radio-frequency cavity, which will be used to decelerate the bunches of antiprotons. At that point, the commissioning team will start changing the energy of the beams. At the same time, a series of general adjustments of the beam optics is as well foreseen.
As antiprotons are difficult to produce and they need to be shared among many experiments, progress in the commissioning of ELENA will also be made using protons and ions coming from a local H– ion and proton source.
via CERN: Updates for the general public
http://home.cern/about/updates/2017/08/first-antiprotons-elena
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