Phase Diagram of the Superconducting States of U_1-xTh_xBe₁₃

A phase diagram is proposed for the different superconducting states in U1-xThxBe13. It suggests that the transition in UBe13 at Tc = 0.87 K should be associated with the lower transition in U1-xThxBe13 (0.02 < x < 0.06). The specific heat and upper critical field results on UBe13, indeed appear to indicate a second superconducting transition at 0.55 K like in the Th-doped systems. Our analysis is practically independent of the form of the super-conducting pairing