Large spectral bandwidth, U.V. solar blind detector

Abstract

An early warning system for detecting the UV from a missile plume has a wide field of view, large spectral bandwidth, solar blind detector. A coated detector passes only a spectral region that embraces UV signals of interest and a wavelength shifter includes a material that shifts the impinging UV energy into a spectrum that embraces the frequencies emitted by fluorescent photons. A photomultiplier tube responsive to the fluorescent emissions provides a responsive read-out indicative of an incoming missile.

What is claimed is:  
     
       1. An apparatus for detecting the UV radiation in missile plume comprising: 
       a photomultiplier tube responsive to fluorescent emissions to provide a representative output signal;  
       a detector having a first surface covered with a first coating having properties to pass the UV radiation and a second coating disposed adjacent the photomultiplier tube having properties to pass the fluorescent emissions, the passbands of the coatings being separate and distinct one from the other, the detector further having a material therein having the properties for shifting the wavelength of the UV radiation to that of the fluorescent emissions.  
     
     
       2. An apparatus according to claim  1  in which the material of the detector is potassium vapor responsive to absorb UV radiation and to transition to a longer wavelength and the first surface presents a wide area, wide field of view UV responsive surface. 
     
     
       3. A method of detecting the UV missile plume within the solar blind UV spectrum comprising: 
       blocking out signals other than a passband including the UV missile plume signals with a first coating;  
       shifting the frequency of the plume signals to a fluorescent bandwidth outside of the solar blind UV spectrum;  
       blocking out signals other than the fluorescent bandwidth outside of the solar blind UV spectrum with a second coating; and  
       amplifying the fluorescent bandwidth.  
     
     
       4. A method according to claim  3  in which the step of shifting includes the transition of UV wavelengths to longer wavelengths fluorescent emission. 
     
     
       5. A method according to claim  4  in which the step of transition includes providing a potassium vapor to receive the information signal passband to assure the transition to the longer wavelengths of fluorescent emission.