A unique high-efficiency particulate air (HEPA) filter medium has been developed for applications in high temperature and high pressure environments. This filter medium is a composite made from quartz and stainless-steel fibers that have been sintered together. The composite medium has the same efficiency and pressure drop as standard HEPA glass media, but has four times the tensile strength and can operate continuously at temperatures up to 500/degree/C. In a conventional HEPA, the binder burns out above 250/degree/C and the medium loses its strength; our composite filter medium has no comparable loss of strength even at 500/degree/C. 8 refs., 8 figs., 1 tab.

A description of experiment E665 at Fermilab is given. Data were taken at muon energies of 500 and 100 GeV and with targets of H/sub 2/, D/sub 2/, and Xe. Initial analysis of the first run's data has commenced. Physics topics addressed by the experiment are given. 1 ref., 1 fig., 1 tab.