Production of argon isotopes by spallation of Sc, Ti, Fe, Co, Ni, and Cu

Spallation ratios and production cross sections of ${}_{}{}^{36,38,39,42}{}_{}{}^{}\mathrm{Ar}$ have been measured for the interaction of 0.080, 0.150, 0.600, 1.05, and 24 GeV protons with scandium, titanium, iron, cobalt, nickel, and copper. Argon is measured by means of a 60° 12 cm radius mass spectrometer, equipped with a gas extraction line and a calibration system. Precision is 1 to 5% for isotope ratios, and 10 to 20% for the cross sections. With regard to spallation reactions, some systematic effects are shown or confirmed. Excitation functions go through a maximum at high energy, then drop asymptotically to a constant value. The ratio of maximum to asymptote cross sections is about 1.6. The spallation ratios depend linearly on the ${\left(\frac{N}{Z}\right)}_T$ ratios of the target and there is probably a linear correlation between the position of the peak of the spallation distribution and the ${\left(\frac{N}{Z}\right)}_T$ ratio. Experimental values are compared with semiempirical fits and some astrophysical implications are discussed.