Some neutron resonance-absorption integrals

Neutron Physics

“…4.1.2. 2 The following relations hold between the de Broglie wavelength A (em) O"n,,, ~ 1&A Ei . (1.3.26 a) W'~--------,--------.-------.…”

“…It is conventional to specify slow-neutron cross sections at this velocity, which corresponds to an energy of 0.0253 ev. 2 A direct proof of the validity of the ltv-law for the capture cross section of light nuclei has not as yet been offered. However, since no resonances appear at low energies, this assumption seems good.…”

“…a IX V and'YI at 2200 m/sec for U233 U235 and PU 239 are tabulated in Special 2,3 NERESON, N., and S. DARDEN: Phys. Rev.…”

“…If we denote the mass and velocity of the neutron by mn and Vn and the mass and velocity of the residual nucleus by mr and V r , then according to the energy conservation theorem (2.3.4) and according to the momentum conservation theorem (2.3.5) Here the plus sign holds when the neutron is emitted at 0° to the direction of the incident y-ray and the minus sign when the neutron is emitted at an angle of 180°. If terms of the order of Ef((m n +mr)c 2 ) are neglected, the calculation yields…”

“…1.3.1. If a current J (cm-2 sec-I) of protons, deuterons, or IX-particles traverses a target substance which contains N identical atoms per cm 3 , the number dQ of neutrons produced per cm 2 and sec in a layer of thickness dx is (2.1.11) Here (] (barn) is the cross section for the neutron-producing nuclear reaction. In integrating Eq.…”