These notes aim to give a somewhat basic introduction to the hows (and occasionally whys) of cryogenics. Cryogenics is not a very well defined term; here I have taken it to mean systems that operate at temperatures of 77 K and below, with the emphasis on systems operating below 4.2 K and above 1 K. The first two temperatures are, of course, the boiling points of nitrogen and helium respectively...

X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of...