Disk-shaped heat-pipe oven used for lithium excited-state lifetime measurements.

A metal-vapor spectroscopic oven based on the heat-pipe principle has been constructed in which the heated stainless steel wicks are mounted on disks spaced closely compared with their radii and in which the window is a glass spacer ring separating the disks and permitting optical access to the active volume. The device has been successfully operated using both sodium and lithium as the working fluid. The lithium 4s S 112 and 5s 2$1/2 radiative lifetimes were measured with this device, yielding values of 56 ± 1.7 and 99 d 9 nsec, respectively.