Studies of the T-³He reaction at two center-of-mass energies relevant to nuclear astrophysics at OMEGA

Nuclear reactions relevant to astrophysics have been studied using the inertial confinement fusion platform as an alternative approach to accelerator-based efforts. The T-³He reaction’s role in big-bang nucleosynthesis as well as being a six-nucleon system makes it a reaction of interest for both astrophysics and basic nuclear science. Experiments at OMEGA used direct-drive exploding pusher implosions with thin-glass-shell capsules to maximize yield at low areal densities. To study the reaction at lower center-of-mass energy (E_CM), the thermal ion temperature (T_ion) for some implosions was decreased by changing the laser pulse shape. The branching ratio for the T(³He,d)α and T(³He,np)α reactions was measured for E_CM less than 100 keV. Additionally, the resonance peak in the T-³He proton spectrum had a smaller peak height for the low E_CM regime, indicating a change in the reaction mechanism with decreasing E_CM similar to observations of the T(T,2n)a neutron spectrum^[1]. To determine T_ion for the T-³He reaction, a method previously developed to infer T_ion from the D-³He proton spectrum^[2] was adapted for this work. Future work will include using this data to constrain R-matrix modeling.



This work was supported in part by NSF, the U.S. DOE, NLUF, LLE, and LLNL.



[1] M. Gatu Johnson et al., Phys. Rev. Lett. 121, 042501 (2018)

[2] P.J. Adrian et al., Phys. Plasmas 32, 022704 (2025)