We describe design studies for a pulsed quasimonoenergetic 2-keV neutron source for calibration of sub-keV nuclear recoils. Such a calibration is required for detectors sensitive to sub-GeV dark matter and also the coherent elastic scattering of reactor neutrinos. In our design, neutrons from a commercial deuterium-tritium generator are moderated to the keV scale and subsequently filtered to achieve a monoenergetic spectrum utilizing the antiresonance feature, characterized by a drop in neutron transmission spectra at 2-keV for scandium. The analyses and conclusions presented are primarily based on simulations, as this study represents a critical first step toward the final goal. We address challenges such as unmoderated high-energy neutrons and gamma backgrounds from neutron capture in the moderator materials. Through optimization of the $\mathrm{moderator}+\mathrm{filter}$ and shielding geometry, we identify a configuration that achieves the target neutron flux at 2 keV while maintaining subdominant rates of background interactions in simulation. Lastly, we outline a future pathway to lower-energy (few eV scale) calibrations using time-of-flight and sub-keV neutrons.

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• Dark matter
• Neutron physics
• Neutron scattering