Missing level corrections in nuclear resonances

Neutron and proton resonances provide detailed level density information. Due to experimental limitations some fraction of the resonances are not observed, and this missing fraction must be determined. The standard correction for missing levels uses the experimental widths and the Porter-Thomas distribution. Analysis of the spacing distribution should yield equivalent information. A general expression for an imperfect spacing distribution (with a fraction of levels randomly missing) was obtained with the maximum entropy principle. This formulation was tested extensively with numerical data and then applied to proton and neutron resonance data sets. Since in Random Matrix Theory the widths and spacings are not correlated, this method complements the conventional approach that considers only the widths. The two analysis methods are compared. (C) 2003 Elsevier Science B.V. All rights reserved.