A MEASUREMENT OF THE 93Nb(n,n')93mNb CROSS-SECTION IN THE ENERGY RANGE 1 TO 6 MeV


Derek B. Gayther and Connell A. Uttley

Harwell Laboratory, Oxon., UK

Michael F. Murphy and William H. Taylor

Atomic Energy Establishment Winfrith, Dorset, UK

Keith Randle

Chemistry Department, Birmingham University, UK

The 30 keV isomer production cross-section in 93Nb excited by neutron inelastic scattering has been measured at ten neutron energies. Small foils of niobium were exposed to high fluences of "monoenergetic" neutrons and the cross-section was determined from the induced K x-ray activities. The detector used in the activation measurements was calibrated with a standard solution of 93mNb which is used as an international reference material for reactor neutron dosimetry. The neutron fluence of the irradiation was measured with a low efficiency 235U fission chamber in which the fissile deposit is located immediately behind the niobium foil. The 93mNb production cross-section is thus determined relative to the 235U(n,f) standard reference cross-section.

KEYWORDS: 93Nb, 30 keV isomer, differential cross-section, activation, fission monitor