The invention discloses a low-
background spectrum unscrambling method based on a
sodium iodide detector. The method comprises the following steps: (1) a gamma
detector after energy calibration actually measures a
radionuclide spectrum and a natural
background spectrum, and
noise reduction is carried out; (2) a
deconvolution algorithm is adopted to process a
gamma energy spectrum after
noise reduction; (3) a peak searching
algorithm carries out searching on all potential peak positions of the
gamma energy spectrum after
noise reduction, and a peak position
list is acquired; and (4) the peak position
list information and a
nuclide library are combined to be together inputted to a
fuzzy logic system, the
system gives the peak position recognition confidence for any
nuclide characteristic peakin the
nuclide library, constraints are set to further adjust the peak position recognition confidence, and thus, a nuclide
list and the nuclide recognition confidence are acquired. The low-
background spectrum unscrambling method based on the
sodium iodide detector has the advantages of accurate peak position reduction, remarkable improvement of energy resolution,
decomposition of an overlapped peak, low error recognition rate, accurate background nuclide analysis and accurate
low activity nuclide analysis, and can be used for nuclide recognition and activity calculation for
radiation monitoring equipment such as a gated
radiation monitor and a nuclide recognition instrument.