Highly oriented pyrolytic graphite (HOPG) is frequently adopted as the reaction target in \(^{12}\) C+ \(^{12}\) C fusion reaction experiments owing to its superior purity. In this study, we investigate the reaction yield dependence on the accumulated beam dose on HOPG target using a novel detection system consisting of a time-projection chamber and silicon array. The reaction yields are significantly reduced under intense beam bombardment owing to radiation damage to the HOPG surface. The \(\alpha _0\) and \(p_{0,1}\) yields decrease by 51.5% and 25%, respectively, when the \(^{12}\) C \(^{2+}\) beam dose accumulates at 5 C. Using the novel detection system and HOPG target, the \(\alpha _0\) yield is determined to be \(2.68^{+4.69}_{-1.69}\) \(\times\) \(10^{-17}\) / \(^{12}\) C after correcting for the yield loss due to radiation damage. Our result represents the highest sensitivity achieved to date in direct measurements of \(^{12}\) C( \(^{12}\) C, \(\alpha _0\) ) \(^{20}\) Ne.
