Radiochemical Determination of Long-Lived Radionuclides in Proton-Irradiated Heavy-Metal Targets: Part I-Tantalum.

In this study, distillation, precipitation, and ion-exchange methods were chosen for the separation of the long-lived β-emitters 129I, 36Cl and the α-emitters 154Dy, 148Gd, 150Gd, and 146Sm from Ta targets irradiated with protons up to 2.6 GeV to determine their production cross sections. Measurements of 129I/127I and 36Cl/35Cl ratios were performed with accelerator mass spectrometry. After separation of the lanthanides, the molecular plating technique was applied to prepare thin samples to obtain highly resolved α-spectra. Autoradiography and focused ion beam/scanning electron microscopy techniques were used to characterize the lanthanide deposited layer. Experimental cross-section data are compared with theoretical predictions obtained with INCL++ and ABLA07 code, and a satisfactory agreement is observed.