Methods for preparing cryo-cooled xenon-derivatized protein crystals have been further developed. SSRL staff designed new tools and developed procedures for easy manipulation of the sample crystal. Samples are first pressurized and then quickly flash-cooled in liquid nitrogen. Two systems based on the original SSRL-CalTech prototype have been fabricated and installed on BL7-1 and BL9-1. Instructions for their use have been documented on the WorldWideWeb site. In addition, a workshop was held (see separate D subproject) which included a lecture as well as hands on training for the preparation of xenon derivatives. Participants of the workshop, as well as other users of the system, have found it simple and safe to use.