Before the PSB became operational in 1972, the protons were directly delivered to the Proton Synchrotron (PS) by the linear accelerator Linac 1, providing the PS with protons of 50 MeV, which were then accelerated by the PS to 25 GeV at beam intensities of approx. 1012 protons per pulse."Klaus Hanke: Past and Present of the CERN PS Booster (2013)" Retrieved on 10 July 2018 However, with the development of new experiments (mainly at the Intersecting Storage Rings ISR), the demanded beam intensities in the order of 1013 protons per pulse exceeded the capabilities of this setup. Therefore, different approaches on how to increase the beam energy already before the protons enter the PS were discussed.
