2006 journal article

Measurement of the relative longitudinal spin-dependent total cross-section difference in (n)over-right-arrow-(d)over-right-arrow scattering


By: R. Foster n, C. Gould, D. Haase, J. Kelley n, D. Markoff n & W. Tornow*

Source: Web Of Science
Added: August 6, 2018

We report relative measurements of the $\stackrel{\ensuremath{\rightarrow}}{n}\ensuremath{-}\stackrel{\ensuremath{\rightarrow}}{d}$ longitudinal spin-dependent total cross-section difference $(\ensuremath{\Delta}{\ensuremath{\sigma}}_{L}){}_{d}$, at ${E}_{n}$(lab) = 5.0, 6.88, and 9.0 MeV. The deuteron target was polarized via dynamic nuclear polarization at 250 mK in a 2.5-T external magnetic field. The target polarization was monitored by nuclear magnetic resonance and was calibrated by a $(\ensuremath{\Delta}{\ensuremath{\sigma}}_{L}){}_{d}$ measurement at ${E}_{n}$(lab) = 1.18 MeV. The polarized neutron beams were produced through the $^{3}\mathrm{H}$$(\stackrel{\ensuremath{\rightarrow}}{p},\stackrel{\ensuremath{\rightarrow}}{n})$$^{3}\mathrm{He}$ and $^{2}\mathrm{H}$$(\stackrel{\ensuremath{\rightarrow}}{d},\stackrel{\ensuremath{\rightarrow}}{n})$$^{3}\mathrm{He}$ reactions. The neutron polarizations were determined either by direct measurement or from known or calculated polarization-transfer coefficients. The results for $(\ensuremath{\Delta}{\ensuremath{\sigma}}_{L}){}_{d}$ show agreement with theoretical calculations based on nucleon-nucleon potential models but are not of sufficient precision to distinguish the presence or absence of three-nucleon force contributions to the cross sections.