Jamieson's group built the counted single-ion implantation capability that underpins every donor spin qubit made at UNSW and Melbourne: individual P, Sb or Bi ions are implanted into silicon through a nanoscale aperture while on-chip detector electrodes register the electron-hole pairs from each ion stop event, so the number and position of dopants is known rather than assumed. Recent directions extend this to high-atomic-number donors for nuclear-spin qudits, to colour-centre creation in diamond and silicon carbide by counted implantation, and to characterising the damage and charge environment those ions leave behind. The work is fabrication-forward but its scientific content is single-particle detection metrology. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — his contribution is upstream: the deterministic creation and validation of the very spin defects whose ensembles are later interrogated by DEER and nanoscale NMR at pT/sqrt(Hz).