The $^{12}$C(n, 2n)$^{11}$C cross section from threshold to 26.5 MeV

TL;DR

This study measured the $^{12}$C(n, 2n)$^{11}$C reaction cross section from just below threshold to 26.5 MeV using monoenergetic neutrons and activation analysis, providing data consistent with the upper band of previous measurements.

Contribution

The paper presents new experimental cross section data for the $^{12}$C(n, 2n)$^{11}$C reaction over a broad energy range, using a novel neutron production and detection method.

Findings

Cross section measurements are consistent with the upper band of previous data.

The method accurately determines neutron flux via $^{1}$H(n,p) scattering.

Provides valuable data for nuclear reaction modeling.

Abstract

The $^{12}$C(n, 2n)$^{11}$C cross section was measured from just below threshold to 26.5 MeV using the Pelletron accelerator at Ohio University. Monoenergetic neutrons, produced via the $^3$H(d,n)$^4$He reaction, were allowed to strike targets of polyethylene and graphite. Activation of both targets was measured by counting positron annihilations resulting from the $\beta^+$ decay of $^{11}$C. Annihilation gamma rays were detected, both in coincidence and singly, using back-to-back NaI detectors. The incident neutron flux was determined indirectly via $^{1}$H(n,p) protons elastically scattered from the polyethylene target. Previous measurements fall into upper and lower bands, the results of the present measurement are consistent with the upper band.