  We investigate spin and charge dynamics of a quantum dot of phosphorus atoms
coupled to a radio-frequency single-electron transistor (rf-SET) using full
counting statistics. We show how the magnetic field plays a role in determining
the bunching or anti-bunching tunnelling statistics of the donor dot and SET
system. Using the counting statistics we show how to determine the lowest
magnetic field where spin-readout is possible. We then show how such a
measurement can be used to investigate and optimise single electron
spin-readout fidelity.
