La cave à bulles

An impromptu sign outside the PS South Hall in 1963 announces the wonders within

From CERN Courier, July 1963 p86 (see later reference):

Neutrino pre-run is a great success

The most exciting news during June was that after years of preparation and the last few months of intense activity to install the equipment for the most complex experiment ever to be attempted at CERN, the neutrino pre-run was a complete success. The proton synchrotron, the fast ejected beam system, the CERN heavy-liquid bubble chamber and the massive spark chamber array all worked smoothly, and everything pointed to the fact that CERN now possesses a new and outstanding tool for scientific research.

Neutrino experiment

Nothing much can be said about the results yet, since this was only a preliminary experiment. However, the kind of particle tracks so far obtained, both in the bubble chamber and in the spark chamber, agree with last year's Brookhaven result that muon neutrinos and electron neutrinos are two different kinds of particle.

At this stage the programme is exploratory and […] the CERN experiments are designed to investigate in more detail the nature of the interactions both of neutrinos and antineutrinos (the latter coming from the decay of negative pions), and to search for the existence of a boson particle, thought by many to be involved in weak interactions in the same way as pions and kaons are involved in strong interactions.