Method and apparatus for testing photomultipliers employing a color temperature correted light source

Claim 1

A PHOTOMULTIPLIER TESTER COMPRISING: AN ELONGATED LIGHT-TIGHT HOUSING A CLOSURE FORMING ONE SIDE THEREOF AND SELECTIVELY OPERABLE TO PROVIDE ACCESS TO THE INTERIOR OF THE HOUSING AND TO ENCLOSE A LIGHT-TIGHT COMPARTMENT INSIDE THE HOUSING; A MINIATURE, CLEAR, SINGLE CONTACT BAYONET TYPE INCANDESCENT FILAMENT LAMP MOUNTED NEAR ONE END OF THE COMPARTMENT AND ORIENTED SUCH THAT ITS AXIS IS DIRECTED TOWARD THE ENDS OF THE COMPARTMENT; GUIDE CHANNELS BETWEEN THE ENDS OF THE COMPARTMENT TRANSVERSE TO THE AXIS OF THE LAMP; A PHOTOMULTIPLIER SOCKET; MEANS MOUNTING SAID SOCKET AND SLIDABLE IN SAID GUIDE CHANNELS INTO AND OUT OF A PREDETERMINED POSITION IN SAID COMPARTMENT TO FACILITATE LOADING AND UNLOADING A PHOTOMULTIPILER UNDER TEST; LIGHT-TIGHT MEANS EXTENDING ACROSS SAID COMPARTMENT INTERMEDIATE THE GUIDE CHANNELS AND THE LAMP, SAID LIGHT-TIGHT MEANS HAVING AN APERTURE FOR TRANSMITTING RADIANT FLUX FROM THE LAMP TO A PHOTOMULTIPLIER UNDER TEST; NEUTRAL DENSITY FILTER MEANS MOUNTED ON SAID LIGHT-TIGHT MEANS ACROSS THE APERTURE THEREIN TO ATTENUATE RADIANT FLUX FROM THE LAMP TO A LEVEL REQUIRED FOR TESTING; ANOTHER LIGHT-TIGHT MEANS EXTENDING ACROSS SAID COMPARTMENT BETWEEN THE LAMP AND SAID FIRST-MENTIONED LIGHT-TIGHT MEANS AND HAVING AN APERTURE LARGE ENOUGH TO TRANSMIT RADIANT FLUX FROM THE LAMP TO ILLUMINATE THE ENTIRE APERTURE OF THE FIRST MENTIONED LIGHT-TIGHT MEANS; A COLOR TEMPERATURE ALTERING FILTER MOUNTED ACROSS THE APERTURE IN THE LATTER LIGHT-TIGHT MEANS FOR ALTERING THE SPECTRAL ENERGY DISTRIBUTED OF FLUX FROM THE LAMP TO APPROXIMATE THAT FROM A FILAMENT OPERATING AT A PREDETERMINED COLOR TEMPERATURE.