Measurement of the 6He Decay Produced by the 9Be(n,$\alpha )$6He Reaction

The OMEGA laser at LLE is routinely used to implode gas-filled capsules to study light ion fusion reaction rates of interest to stellar nucleosynthesis. As a first step toward a possible measurement of the $^{\mathrm{3}}$H(t,$\gamma )^{\mathrm{6}}$He radiative capture reaction, a detector system capable of measuring the 801 ms half-life of $^{\mathrm{6}}$He has been developed and is being tested using $^{\mathrm{6}}$He nuclei produced via the $^{\mathrm{9}}$Be(n,$\alpha )^{\mathrm{6}}$He reaction. Deuterons from the SUNY Geneseo tandem Pelletron produce neutrons in a thick deuterated polyethylene target via the $^{\mathrm{2}}$H(d,n)$^{\mathrm{3}}$He reaction. These neutrons are allowed to strike a beryllium target placed in front of a silicon $\Delta $E-E detector telescope, which is used to identify the $\beta $ particles from $^{\mathrm{6}}$He decay. Following an approximately five second long activation period, the beryllium sample is immediately counted for about five seconds. The pulse heights for each detector and the timestamp are recorded using a specially configured femtoDAQ acquision system and used to measure the decay curve. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.