Method and apparatus for detecting fluorescence

An apparatus for detecting fluorescence of an unknown target material being excitable at an excitation wavelength and fluorescing at a fluorescing wavelength, comprising:

• a reference material;
• an energy source arranged to excite both said target material and said reference material at approximately said excitation wavelength;
• power supply means for supplying electrical power having an adjustable voltage to said energy source;
• an excitation filter optically arranged between said energy source and both of said target material and said reference material, said excitation filter passing light energy at approximately said excitation wavelength;
• a reference detector means optically arranged to be responsive to and for detecting light emitted from said reference material at approximately said fluorescing wavelength;
• a target detector means optically arranged to be responsive to and for detecting light emitted from said target material at approximately said fluorescing wavelength;
• reference measurement means for generating a reference output in response to said reference detector means in order to determine the amount of fluorescence generated by said reference material;
• target measurement means for generating a target output in response to said target detector means in order to determine the amount of fluorescence generated by said target material;
• reference calibration means coupled to said reference measurement means and to said power supply means for varying the electrical voltage supplied to said energy source and for calibrating said reference output;
• and
• target calibration means coupled to said target measurement means for calibrating said target output in response to a known target material.