Operation of the APS-U injectors with high single bunch charge

The APS-Upgrade uses swap-out injection, which means the injectors must supply a full charge bunch (up to 16 nC) to replace a depleted one in the storage ring. The APS injector chain consists of a linac, particle accumulator ring (PAR), and booster synchrotron. These machines were kept in place for the APS-U, with several key upgrades to support high charge operation. Major upgrades include a new timing system, improved diagnostics, and a new amplifier for bunch compression in the PAR. So far, the injectors have supported up to 140 mA storage ring current in the high charge (48 bunch) mode. This talk will summarize the work needed to achieve high injector charge, and report on operational experience so far.