Fifty Years of Synchrotrons

The idea of a pulsed magnet ring, fundamental to the synchrotron, appeared in a proposal by Oliphant [1] in 1943 and was followed by the independent discovery of phase stability by Veksler [2] in 1944 and McMillan [3] in 1945. This opened the door to a demonstration of synchrotron acceleration to 8 MeV by Goward and Barnes [4] in a converted betatron at Woolwich Arsenal, UK. The event, which took place in August 1946, was followed only two months later by the operation of the General Electric Laboratory's 70 MeV machine at Schenectady, USA built by Elder, Gurewitsch, Langmuir and Pollock [5]. The fifty years that follow have seen projects spanning almost six orders of magnitude in energy. The phenomenal success of the synchrotron principle was sustained by two other important discoveries, that of alternating-gradient focusing and the use of colliding beams. This paper records the major landmarks in the early history of the synchrotron.