Accepted Thursday Oct 22, 2009
A new method is proposed to determine the energy dependent spin distribution in experimental nuclear level schemes. This method compares various experimental and calculated moments in the energy-spin plane in order to obtain the spin-cutoff parameter s as a function of mass A and excitation energy using a total of 7202 levels with spin assignment in 227 nuclei between F and Cf. A simple formula, s2 = 0.391 ·A0.675(E-0.5 ·Pa)0.312, is proposed up to about 10 MeV which is in very good agreement with experimental s values and is applied to improve the systematics of level density parameters.