Sample identification by measurement of wavelength of luminescence utilizing plasma discharge lamp excitation and continuous interference filter

Claim 1

Apparatus for identifying in terms of an electrical output the wavelength of the luminescence emitted by a luminescent sample under exciting radiation by analysing the intensity of emitted radiation at different wavelengths, said apparatus comprising a sample station whereat a sample may be suppOrted at a predetermined location, a plasma discharge flash lamp for producing exciting radiation flashes of high peak intensity over a continuous range of wavelengths in a luminescence exciting region, an electrical supply circuit including a capacitor for storing electrical energy and discharging through said lamp with a high repetition rate, means for defining the path boundary of a beam of light directed in operation from the lamp to the sample under test, a transducer arranged to receive the luminescence emitted from the sample in a direction not included in said boundary at the substantial exclusion of direct rays from the lamp, said transducer being capable of providing an electrical output related to the intensity of the luminescence falling thereon, and a continuous filtering arrangement including wavelength selective interference filter means, providing over its area a stepless variation in wavelength transmission over a predetermined range and mounted for movement past the transducer, for varying the wavelength of said luminescence to enable said transducer to provide an electrical output related to intensity of said luminescence at different wavelengths, said filter means enabling the wavelength of the luminescence to be identified in terms of the electrical output of the transducer as the successive portions of the continuous filter corresponding to successive wavelengths in said pre-determined range are scanned past the transducer.