Fission-fragment sources containing 252Cf and 244Cm

The measurable features and the accuracy of measuring those features along with certification procedures are discussed for fission fragment sources containing 252Cf and 244Cm. Methods have been devised based on nuclear-physics constants related to the main and impurity nuclides. Data are given for these nuclides, including their alpha decay and spontaneous fission half-lives and their →-particle energies. The basic certified quantity is the fragment radiation activity. Certification and measurement methods based on ionization chambers and radiometers containing semiconductor detectors and a method which employs spectrometry and alpha radiation measurement were comparatively evaluated for efficiency and energy resolution. The latter method measures activity from the alpha emission where the α spectra is measured by a silicon surface-barrier detector. The methods and means of measurement provide for certifying routine fission fragment sources on fragment radiation activity with errors of 1.3% for 0.95 confidence probability