Pionic Fusion of $^{\mathrm{4}}$He $+ \quad^{\mathrm{12}}$C

Pionic fusion is the process by which two nuclei fuse and then deexcite by the exclusive emission of a pion. These reactions represent the most extreme examples of deep subthreshold pion production and provide evidence for an unknown, collective mechanism for pion production. An experiment was performed at the Texas A{\&}M University Cyclotron Institute to measure the cross section of the $^{\mathrm{4}}$He $+ \quad^{\mathrm{12}}$C $\to $ $^{\mathrm{16}}$N $+ \quad \pi^{\mathrm{+}}$ reaction. The Momentum Achromat Recoil Spectrometer (MARS) was used to separate and identify the $^{\mathrm{16}}$N fusion residues and the newly constructed Partial Truncated Icosahedron (ParTI) phoswich array was used to identify charged pions. The detector responses for each phoswich unit were recorded using fast-sampling ADCs which allow all light charged particles in the ParTI phoswiches to be identified using ``fast vs. slow'' pulse shape discrimination. By writing the waveform responses, pions can also be identified by the presence of a characteristic muon decay pulse. The combination of the residue-pion coincidence and the two independent pion identification techniques represent a highly sensitive experimental design for studying pionic fusion reactions.