Prospects for Bose-Einstein condensation of metastable neon atoms - art. no. 023607

The calculated upper limit K(i)(pol)less than or equal to 10(-14) cm(3)/s o f the rate constant for suppressed ionization in a gas of metastable Ne(P-3 (2)) atoms in the fully aligned \J=2,m(j)=2] state is used as input to inve stigate the prospects for achieving Bose-Einstein condensation (BEC). The h eating rate of the trap population by secondary collisions of the hot produ cts of the process of ionization-i.e., ground-state atoms, ions, and dimer- ions-with cold trapped metastable atoms is discussed in terms of a semiclas sical model. An important step lies in limiting the depth of the magnetic t rap to a value of a few millikelvin, to limit the range of small-angle scat tering that contributes to heating. Also, a tight radial confinement reduce s the probability for secondary collisions. At a trap depth of 10 mK, a rad ial dimension of 3 mu m, and a density of 2 x 10(13) cm(-3) the heating rat e is 1.4 mu K/s, which should be compared to the transition temperature to BEC of 0.6 mu K. The collisional heating is dominated by ion-metastable-ato m collisions, due to their long-range charge-induced dipole interaction. Ke eping the evaporative cooling switched on at T=T-C reduces the heating a hu ndredfold. Using a bright beam of laser cooled neon atoms, an initial popul ation of greater than or equal to 10(10) atoms can be loaded into a magneto -optical trap in one second. Tight magnetic traps are easy to achieve for m etastable neon atoms, due to their magnetic moment of 3 mu(B). We conclude that achieving BEC is feasible for metastable neon. This also holds for tri plet metastable helium, once the loading rate of traps has been improved. F inally, the semiclassical model used for calculating the heating rate is ap plicable to a wide range of inelastic collisions in trapped alkali gases an d/or collisions with background gas.