Astrophysical S factor for dd interaction at ultralow energies

Experimental results are presented that were obtained by measuring the astrophysical S factor for dd interaction at very low deuteron collision energies by using the liner-plasma technique. The experiment was performed at the high-current generator of the High-Current Electronics Institute (Tomsk, Russia). The values found for the S factor at the deuteron collision energies of 1.80, 2.06, and 2.27 keV are Sdd=114±68, 64±30, and 53±16 keV b, respectively. The corresponding dd cross sections obtained as the product of the barrier factor and the measured astrophysical S factor are σ dd n (Ecol=1.80 keV)=(4.3±2.6)×10−33cm2, σ dd n (Ecol=2.06 keV)=(9.8±4.6)×10−33cm2, and σ dd n (Ecol=2.27 keV)=(2.1±0.6)×10−32cm2.