Implementation of Single Klystron Working Mode at the ALBA Linac

ALBA is a third generation synchrotron light source whose injector consists of a 100 MeV Linac and a Booster that accelerates the beam up to the full energy, 3 GeV. Two pulsed klystrons are used to feed the Linac cavities. Klystron 1 feeds the bunching section and also the first accelerating structure. Klystron 2 feeds exclusively the second accelerating structure. Recently, a S-band switching system installed in the waveguide system allows us to use also Klystron 2 to power the low-energy section and operate the Linac at lower energy, around 65 MeV. So that injection into the Booster is still possible while, in the meantime, Klystron 1 can be connected to a dummy load for reparation. Therefore, the time response after a klystron failure is improved. Details of the waveguide upgrade and the results of the ALBA Linac operated with only one klystron are presented.