Means are illustrated for electronically exciting phosphor material to provide a source of photon energy for pumping active negative temperature media. Preferably the phosphor has a fast decay time and is so chosen that its emission spectrum substantially matches or coincides with the absorption spectrum of the active negative temperature medium. The source of electrons may be a conventional cathode, or alternatively, one of special construction.
This application is a continuation of application Ser. No. 808,703, filed Mar. 19, 1969, now abandoned, which was a continuation of application Ser. No. 641,710, filed May 26, 1967, now abandoned, which was in turn a continuation of application Ser. No. 265,461, filed Mar. 15, 1963, also now abandoned.
An applique armor system includes a plurality of armor tiles, each armor tile being a composite armor member with a sheet ceramic armor component, an impedance match enhancing sheet member of material such of metal or polymer material adhered to the surface of the ceramic sheet member remote from the anticipated direction of attack, and a compliant separable fastener component of extended area type secured to a surface of the composite armor tile, the ceramic sheet member preferably having a thickness at least ten times the thickness of the impedance match enhancing sheet member.
