The PolFusion Experiment: Measurement of the dd-Fusion Spin-Dependence

A double-polarized dd-fusion experiment is under preparation at PNPI, Gatchina. The experimental program includes the measurements of the asymmetry in the differential cross section of the reactions \(\overrightarrow{\text {d}}+\overrightarrow{\text {d}} \rightarrow {^3}{\text {He}}+{\text {n}}\) and \(\overrightarrow{\text {d}}+\overrightarrow{\text {d}}\rightarrow {\text {t}}+{\text {p}}\). The spin-correlation coefficients \(C_{z,z}\) and \(C_{zz,zz}\) will be measured to determine the quintet-state suppression factors for both reactions, for which quite different theoretical predictions were made and which are very important for the design of future neutron-lean fusion reactors. The total cross section modification for polarized d–d fusion will also be investigated. An increase by a factor of 1.5 was already deduced for the \(\mathrm {d}+ {^3}\mathrm {He}\) and the \(\mathrm {d}+\mathrm {t}\) reactions. The experimental setup and the future upgrade plans are described.