Analysis of residual stresses in a copper cover produced by thermal projection on super-conducting niobium cavities

Since last three years, we study the possibility to stiffen the niobium sup erconducting cavities by thermal sprayed copper coating. The important resi duel stress could been generated in the copper coating and in the supercond ucting substrat of niobium after thermal projection, the analysis of residu el stress is necessary. The X-ray diffraction method is often used to deter minate the residuel stress. In the work, the X-ray diffraction is used to e valuate the stress distribution in the copper coating and in the niobium su btrat. This kind of analysis for a copper coating realized onto a niobium s ubstrat have never been determinated before, so the results of this work ar e news. An analytical calculation have been developed to understand the sou rce of residuel stress and the experimental observations.