• B.M. Sabirov
  JINR, Dubna, Moscow Region

The results obtained by the JINR/Dubna-RFNC/Sarov-FNAL/Batavia-INFN/Pisa in designing the fourth-generation cryomodule for the ILC are reported. A technology for making a bimetallic Ti+SS tube transition element by the explosion welding method has been developed and implemented for the first time. All Ti+SS samples were subjected to the metallografic analysis and tested for strength and leaks at different cryogenic temperatures. The leak rate at 1.8K was <10(-11)Pa.m(3)/s.For redesign cryomodule helium vessel we developed Nb+SS transition elements using explosion welding technology. Preliminary tests shown reliable strehgth and density of joint Nb+SS bonds. Upper limit of leak rate is (3-5).10(-10)atm.cc/s.