Diffraction-limited storage rings (DLSRs) have restricted
dynamic apertures (DAs) due to their ultralow emittances and very
strong nonlinearity. Off-energy multipole kicker injection (MKI)
scheme, in which off-energy beam is injected onto the corresponding
off-energy orbit, can reduce the requirement of DAs. However, it
requires relatively large energy acceptance and high dispersion
bumps. For a DLSR lattice with relatively large energy acceptance
and off-momentum DAs, off-energy beam can be injected into the
off-momentum DA but with an additional offset from the off-energy
closed orbit to increase the total offset of the injected beam from
the on-energy closed orbit, which is favorable to the application of
the off-energy MKI. In this paper, such an off-energy MKI is
designed for a DLSR, and an acceptance analysis method based on 6D
particle tracking is utilized to design and optimize this injection
scheme. Detailed simulation is carried out, and the results
demonstrate the feasibility of this injection scheme.