Abstract
| At the end of LS2, Linac4 became the new injector of the CERN proton accelerator complex. The previous Linac4 source version, the IS03, produced an operational beam current of 35 mA, which resulted in 25 mA after the RFQ. This limited transmission was mainly due to the extracted beam emittance exceeding the acceptance of the RFQ. A new geometry of the Linac4 source extraction electrodes has been developed with the aim of decreasing the extracted beam emittance and increasing the beam current and transmission through the RFQ. The new source, the IS04, has been studied in simulations, and thoroughly tested at the Linac4 test stand. Following the 2021 test campaign, the IS04 has been installed as operational source in the Linac4 tunnel at the start of 2023 and has been successfully tested for the operational 25 mA peak current after the RFQ. |