Measurement of the Electron-Neutron Interaction by the Asymmetrical Scattering of Thermal Neutrons by Noble Gases

Abstract

The electron-neutron interaction has been obtained from measurements of thermal neutron scattering by argon, krypton, and xenon. In terms of the slope of the electric structure factor of the neutron at zero momentum transfer, the values obtained were 0.0196±0.0013 F 2 from Ar, 0.0197±0.0007 F 2 from Kr, and 0.0190=1=0.0005 F 2 from Xe. The final result is 0.0193 ±0.0004 F 2 , which corresponds to an electron-neutron scattering length of -1.34db0.03XlO~1 6 cm and an effective potential of -3720=b90 eV. During the course of the experiment, the neutron-absorption cross sections of krypton and xenon (at 2200 m/sec) were measured by transmission and found to be 25.0=1=0.8 b and 25.1=1=1.0 b, respectively. Also, some free-atom thermal-neutron scattering cross sections were measured. The results were 2.415=1=0.010 b for neon, 0.647 ±0.003 b for argon, 7.61=1=0.04 b for krypton, 4.30=1=0.02 b for xenon, 73.7=1=0.4 b for 36 Ar, 1.705=1=0.009 b for 22 Ne, and 5.1=1=0.3 b for 21 Ne. 1425Ne. (1966.

Neutron scattering and extra-short-range interactions

“…We propose improving the experiment [24] and measuring the forward-backward asymmetry of the scattering of neutrons at atoms of noble gases, in the following way: the initial velocity of the neutrons should correspond to the range of very cold neutrons (VCN); the double differential measurement of neutron velocity before/after scattering should be used to calculate the transferred momentum for every collision. Fig.…”

Coherent nuclear scattering amplitudes of germanium, copper and oxygen for thermal neutrons

“…The excellent work of Batterman & Chipman (1962) provides the Debye temperature 0Ge=290 (5)K with just less than sufficient precision to draw significant conclusions here. The discrepancy between the theoretical (Foldy, 1951) and experimental (Krohn & Ringo, 1966, 1973 values for the neutron-electron interaction must then be resolved by other means.…”

Fundamental Neutron Physics

“…One set comes from measurements of the asymmetric angular distribution of neutron scattering in noble gases, a ne = (−1.33 ± 0.03) × 10 −3 fm [374,375], and the total cross section of lead, a ne = (−1.33 ± 0.03) × 10 −3 fm [376]. The other set comes from measurements of the total cross section of bismuth, a ne = (−1.55 ± 0.11) × 10 −3 fm [377], and neutron diffraction from a tungsten single crystal, a ne = (−1.60 ± 0.05) × 10 −3 fm [378].…”