Speaker
Description
The $^{12}$C(α, γ)$^{16}$O reaction is a pivotal process in nuclear astrophysics. Due to its extremely low cross section (~10$^{-17}$ barn) within the Gamow window, directly measuring this reaction is highly challenging. An irradiation-resistant $^{12}$C-enriched target is a key technique for the direct measurement of the $^{12}$C(α, γ)$^{16}$O reaction. In this work, we developed a $^{12}$C-enriched diamond target on Mo substrates using the chemical vapor deposition (CVD) method. The target demonstrates excellent stability under bombardment with a high-intensity proton beam. A 1.5% deterioration in $^{12}$C thickness was observed after bombardment by a 270 keV, 2 mA proton beam with a charge of 125 C, indicating a significant improvement over typical carbon targets. The $^{13}$C/$^{12}$C ratio in the target was determined to be (1.1 ± 0.3) × 10$^{−4}$, indicating no contamination was introduced during the CVD process. A method for determining the hydrogen content in coatings based on nuclear reactions is presented. The upper limit of the hydrogen content in the diamond 12C-enriched target was found to be 0.075%. The irradiation-resistance capacity and isotopic purity of the target meet the requirement for direct measurement.
