SIMS investigation of the spallation and transmutation products production in lead

Abstract

The production of spallation and activation products in liquid metals (Pb or Pb–Bi) is an important issue in the frame of the MEGAPIE and other ADS studies. Although it is usually evaluated by well established codes like the MCNPX, experimental validations of the calculations in real conditions are rare. This work is an attempt to deliver experimental data using the material irradiated in the Swiss Spallation source (SINQ). A target composed of SS316L cladding tubes filled with Pb was irradiated in SINQ with a total proton charge of 10.03 Ah. A cross-section of one rod has been prepared for analysis in the PSI fully shielded secondary ion mass spectrometer (SIMS). Mass scans have been realized on one irradiated specimen and compared to a reference un-irradiated sample. The SIMS measurement delivers no absolute quantitative measurements but allow the determination of the mass distribution of the long lived spallation and activation products in real materials. The analysis shows the production of a raw of isotopes in the mass range 50–140 amu in agreement with calculation realized in model cases. The measurements across the specimen demonstrate also the homogeneity of the spallation and activation products content in the rod cross-section. This analysis provides useful information on the long lived isotopes production in lead based spallation targets like MEGAPIE.