CERN Courier vol 42 no 4 : May 2002 UA1 detector detecteur 1981 1981 The UA1 detector, shown here in its 'garage' position, was a multi-purpose detector. It covered as large a solid angle as possible and could detect hadron jets, electrons and muons. This was used between 1981 and 1993 on the SPS collider at CERN to observe the proton-antiproton collisions. UA1 was used along with UA2 to discover the W and Z bosons in 1983, which lead to Nobel Prizes for Carlo Rubbia and Simon van der Meer in 1984. CERN Courier vol 43 no 4 : May 2003 1983 1983 This image taken by the UA1 experiment on 30 April 1983 was the first detection of a Z0 particle. UA1 observed proton-antiproton collisions on the SPS between 1981 and 1993 to look for the Z and W bosons, which mediate the weak fundamental force. The Z0 decays very quickly so cannot be seen, but the electron-positron pair produced in the decay can be seen in blue. CERN Picture Packs : The Z Story 1987 1987 Detector for the UA2 experiment, for the study of proton-antiproton collisions in the SPS between 1981 and 1993. It was used, along with UA1 (another experiment on the SPS), to discover the W and Z bosons in 1983, which won Carlo Rubbia and Simon van der Meer the Nobel Prize in 1984. Laurent Guiraud Microcosm 1999 1999 <!--HTML-->Photo 09 : CERN's Director General, Luciano Maiani, at the opening of an exhibition about the Weak Force in Microcosm. <br>Photo 01 : CERN's Director General, Luciano Maiani, looking at the UA1 central detector at the opening of an exhibition in Microcosm. United Kingdom Outreach : Picture of the Week 1982 1982 The discovery of the W particle in the UA1 detector from the October-December 1982 run of the proton-antiproton collider, producing a high transverse energy electron (arrowed). This particle is produced back-to-back with 'missing energy', indicative of the emission of an invisible neutrino. The UA1 detector ran on the SPS accelerator at CERN between 1981 and 1993.