  An on-axis injection scheme using a double-frequency RF system in a storage
ring with small dynamic aperture is proposed. By altering RF voltages, empty RF
buckets can be created which will be used for on-axis injection. After bunches
are injected, a reverse RF voltage altering process is performed and the
injected bunches can be longitudinally dumped to the main RF buckets. The
scheme allows reaping the advantages of the on-axis injection while still
performing accumulation.
