Optical flow cryostat with rotatable sample stage

Abstract

Matrix isolation of atoms and molecules for energy studies is very popular. In such work, an atom, molecule, adduct, or cluster is isolated in a solid “gas” matrix, which tends to act as a rigid vacuum. For example, a single atom may be frozen in argon, so that its properties as an isolated atom may be measured, usually by spectroscopic means. The many variations on this approach include studying clusters of atoms or molecules at low temperature and in magnetic fields. For this type of work, and other work as well, we designed and constructed a liquid helium flow cryostat that has the following advantages: it is small and light, so that it may be mounted on almost any spectrometer; it has a short (8 minute) cool down and warm up time; the sample stage may be rotated while cold, allowing it to be exposed to a number of gas nozzles for sample growth and optical access windows for measurements; and the cryostat is very simple and inexpensive to construct.