Low temperature D-T fusion neutron irradiation experiment of metals with the rotating target neutron source II (RTNS-II) at LLNL

A low temperature D-T fusion neutron irradiation was done for the various kinds of metals with the Rotating Target Neutron Source II (RTNS-II) at Lawrence Livermore National Laboratory. Most of the specimens were discs of 3 mm in diameter which were pre-thinned for transmission electron microscopy, and irradated below 20 K at the fluence of 1015 to 1017 n/cm2 with HELI-TRAN cryostat of liquid helium flow type. After the irradiation, they were cryotransferred to the electron microscope specimen chamber using specially designed cold holder. Displacement cascade damages and their subsequent relaxation during annealing were observed. The lowest temperature at which specimens were cryotransferred and observed in the present experiment was 130 K. This report is to describe the details of the experimental techniques and procedures. (author)