Patent ID: 7247855

Claim:
A nuclear material detector, comprising: a scintillating fiber radiation sensor, said scintillating fiber radiation sensor emitting light when bombarded by gamma particles; a light detector optically coupled to said scintillating fiber radiation sensor, wherein said light detector detects light emitted by said scintillating fiber radiation sensor and outputs corresponding electrical signals; a conditioning circuit in operable communication with said light detector, wherein said conditioning circuit conditions the electrical signals output by said light detector for further processing; a frequency shift keying (FSK) circuit in operable communication with said conditioning circuit, wherein said FSK circuit converts the conditioned electrical signals output by said conditioning circuit into corresponding sinusoidal signals; a fast Fourier transform (FFT) circuit in operable communication with said FSK circuit, wherein said FFT circuit converts the sinusoidal signals into corresponding spectral lines; an electronic controller in operable communication with said FFT circuit, wherein said electronic controller is programmed with a table mapping frequencies of the spectral lines to corresponding radioactive isotopes; and an amplitude spectral addition circuit in operable communication with said electronic controller, wherein said amplitude spectral addition circuit sums the spectral lines output by said FFT circuit having equivalent frequencies, thereby producing a cumulative spectral line for each radioactive isotope detected.