Miniature Cryostats: Design and Application to Matrix‐Isolation Studies

A cryostat of novel design has been constructed and tested for use in matrix‐isolation spectroscopy at low temperatures. The refrigeration is supplied by a built‐in miniature open‐cycle Joule‐Thomson liquefier which operates from tanks of high‐pressure nitrogen and hydrogen. At 15–16°K, the lowest temperature that can be achieved, the device supplies up to 2 W of refrigeration. The temperature of the cold window on which the matrix is deposited can be varied continuously in the range 15–200°K and readily controlled to ±0.3°K or better. The small, compact, and efficient cryostat design that has been achieved permits great flexibility of coupling to spectrometers and other instruments, and offers many interesting possibilities for a variety of other applications.