NEUTRON-CAPTURE CROSS-SECTIONS OF EUROPIUM AND LUTETIUM ISOTOPES FROM 0.01 TO 10 EV

Absolute neutron-capture cross-section measurements from 0. 01 to 10 eV employing a Moxon-Rae detector and conventional time-of-flight techniques are described. For the calculation of multiple-scattering and gamma-ray attenuation effects in samples, new improved methods were developed. Cross-section curves were evaluated for the elements europium and lutetium as well as for the isotopes **1**5**1Eu, **1**5**3Eu, **1**7**5Lu. The cross sections could be determined to an accuracy of better than 5%; however, for some resonance cross sections the total error increases up to 10%. These cross sections are needed for different purposes such as detector applications, fission-product poison calculations, burnup calculations, flux measurements, and others.