Collisional Properties of Cold Spin-Polarized Metastable Neon Atoms

We measure the rates of elastic and inelastic two-body collisions of cold spin-polarized neon atoms in the metastable ³P₂ state for ²⁰Ne and ²²Ne in a magnetic trap. From particle loss, we determine the loss parameter of inelastic collisions β=6.5(18)×10^-12 cm³ s^-1 for ²⁰Ne and β=1.2(3)×10^-11 cm³ s^-1 for ²²Ne. These losses are caused by ionizing (i.e., Penning) collisions and occur less frequently than for unpolarized atoms. This proves the suppression of Penning ionization due to spin polarization. From cross-dimensional relaxation measurements, we obtain elastic scattering lengths of a=-180(40)a₀ for ²⁰Ne and a=+150_-50⁺⁸⁰a₀ for ²²Ne, where a₀=0.0529 nm.