  Many experiments in the field of optical levitation with nanoparticles today
are limited by the available technologies for particle loading. Here we
introduce a new particle loading method that solves the main challenges, namely
deterministic positioning of the particles and clean delivery at ultra-high
vacuum levels as required for quantum experiments. We demonstrate the efficient
loading, positioning, and repositioning of nanoparticles in the range of
$100-755\,\mathrm{nm}$ diameter into different lattice sites of a standing wave
optical trap, as well as direct loading of nanoparticles at an unprecedented
pressure below $10^{-9}\,\mathrm{mbar}$. Our method relies on the transport of
nanoparticles within a hollow-core photonic crystal fiber using an optical
conveyor belt, which can be precisely positioned with respect to the target
trap. Our work opens the path for increasing nanoparticle numbers in the study
of multiparticle dynamics and high turn-around times for exploiting the quantum
regime of levitated solids in ultra-high vacuum.
