G. Hacken

Recent Experimental Neutron Resonance Spectroscopy Results as a Test of Statistical Theories of Short and Long Range Order for Level Spacings

During 1968 and 1970, we obtained large amounts of high quality neutron resonance spectroscopy data using the Columbia University Nevis Synchrocyclotron. This report emphasizes our experimental results for even-even nuclei having 150 < A < 190. In the oast, attempts to make detailed comparison of experimental resonance energies for nuclei for such “best test” cases as Th232 or U238 with theory gave poor fits for those tests which assumed that a single s level population only was present, and were sensitive to the inclusion of a partial extra p level population. For 150 < A < 190, the s level strength function S0 is sufficiently greater than the p level strength function S1 that all p levels tend to be weaker than all but a very small fraction of the s levels, providing a better separation of the two populations. Our results for Erl66, Erl68, wl82, wl84, Sml52, and Ybl72 were of particularly good quality, and give good agreement with the following statistical tests. Except for Er168, they seem to have only s levels, and for Er168 the p levels can be cleanly separated out on the basis of their strength.