Ar Reaction.*

To investigate the use of argon as a deuteron beam stopping material, the ⁴⁰Ar(d,p)⁴¹Ar cross section was measured at average deuteron energies of 3.6 MeV, 5.5 MeV, and 7.0 MeV using an activation method with nickel degraders. The ^natNi(d,x)⁶¹Cu reaction has historically been one of only a few IAEA-recommended deuteron beam monitor reactions. A discrepancy was observed between the accepted and measured values of the intensity ratio of the two strongest gamma rays following ⁶¹Cu β decay. This has significant impact to published cross sections measured in ratio to that beam monitor cross section. To determine the error's magnitude, over a hundred measurements of the 283 keV to 656 keV gamma-ray emission ratio were collected from seven experiments and a variety of detectors and geometries. A weighted average indicates an error in the value listed in the Nuclear Data Sheets of 11%. Following this correction, the ⁴⁰Ar(d,p)⁴¹Ar cross section was determined from activation to be ~40% higher than a previous measurement and an order of magnitude higher than TENDL, further demonstrating the need for multiple, independent measurements of often-accepted nuclear data.