50 years of the Super Proton Synchrotron: CERN's all-rounder gets particles moving
Since 1976 the SPS at CERN has accelerated particles – today as the last stage before the LHC. It enabled the discovery of the W and Z bosons in 1983. CERN has now celebrated its 50th birthday.
Photo: Gillis / Wikimedia Commons, CC BY 3.0 (cropped and resized)
Video: YouTube · CERN · youtube.com
The Super Proton Synchrotron (SPS), the second-largest accelerator at the CERN research centre near Geneva, has turned 50. At a symposium on 8 October, CERN celebrated the anniversary and showed a new video on the machine's history. Its official commissioning date is 17 June 1976, when the SPS reached an energy of 400 gigaelectronvolts (GeV). The ring tunnel is 6.9 kilometres long and runs beneath the French-Swiss border.
Over five decades, the SPS has accelerated protons, antiprotons, electrons, positrons as well as oxygen and lead ions – as an accelerator, a collider and an injector. Its greatest success came in 1983 with the discovery of the W and Z bosons by the UA1 and UA2 experiments, when the SPS was colliding protons and antiprotons. Carlo Rubbia and Simon van der Meer received the 1984 Nobel Prize in Physics for this. According to CERN, the machine also helped develop technologies such as the touch screen.
Today the SPS is the final injector for the Large Hadron Collider (LHC): it takes protons from 26 to 450 GeV before the LHC accelerates them further. It also supplies beams to fixed-target experiments such as COMPASS, NA61/SHINE and NA62.