He got his MSc and an NUI Travelling Studentship in Experimental Physics in 1934 and worked for one year in Paris with the eminent cosmic ray physicist Pierre Auger.
[2] From 1935 to 1938 he did postgraduate research at the Cavendish Laboratory, Cambridge, where he was mentored by Lord Rutherford and concentrated on nuclear physics.
[4] Ó Ceallaigh remained at Cork until 1947, during which time he was conferred with the degree of Ph.D.,[5] and then took a position at the University of Bristol working in a group assembled by the Nobel Prize winning particle physicist C F Powell.
Bristol was at the time the worldwide centre of cosmic ray research, and O'Ceallaigh, nurtured by Rutherford and Powell, two of the greatest experimental physicists in history, soon became one of its leading figures.
[1] Their research into cosmic rays, involving pions, kaons,[6] and neutrinos, helped to establish The Standard Model of particle physics.