Table 1 Temperature limits.

From: Blue-sky bifurcation of ion energies and the limits of neutral-gas sympathetic cooling of trapped ions

Gas α (a.u.) ρ (cm−3) T n T create T u T maintain
3He 1.38 1014 170 mK 10 K 2 K 300 mK
4He 1.38 1014 4 K 10 K
23Na 163 1012 100 μK 30 K 800 mK 200 μK
87Rb 319 1012 10 μK 30 K 800 mK 40 μK
40Ca 157 1010 4 mK 300 K
  1. Expected steady-state temperatures of Ba+ ions for the large Ni limit (Ni≥32) after being immersed in a variety of gases with polarizabilities α, densities ρ and temperatures Tn. Tcreate (Tmaintain) is the temperature reached if the ions are initialized above (below) Tu.