同位素150Sm和147Sm核反应靶的制备OA

The 150Sm and 147Sm isotopic targets are needed in the Coulomb excitation experiments to study the nuclear structure of Sm isotopes in the rare-earth region.A novel reduction-distillation apparatus was designed and established to efficiently reduce 150Sm2O3 and 147Sm2O3 to 150Sm and 147Sm,respectively.The high temperature reduction-distillation technique of Sm2O3 was studied,and successfully used to reduce and distill 150Sm2O3 and 147Sm2O3 powders to stalactite-shaped metallic 150Sm and 147Sm,respectively.The reduction temperature was measured by an infrared thermometer(CIT-1TD).The impurity element contents were tested before and after reduction-distillation using an inductively coupled plasma optical emission spectrometer(ICP-OES).The results show that Zr is preferably selected as the reducing agent,the closed-type water-cooled DLC/Cu needle is used as a better collector,the optimal reduction temperature and reduction time are respectively 1 500 ℃ and 30 min,the reduction-distillation efficiencies of 150Sm2O3 and 147Sm2O3 are respectively 94.8％and 95.3％,almost no additional impurities are introduced during the reduction-distillation process.The self-supporting metallic 150Sm and 147Sm targets were prepared by rolling technique.During the whole rolling process,the clean stainless-steel clips were used as a transition in order to achieve high-efficiency rolling of 150Sm and 147Sm while minimizing impurity contamination,and the indoor humidity was maintained over 60％to prevent the 150Sm and 147Sm targets from ignition.The thickness values of self-supporting 150Sm and 147Sm targets were measured using a balance(XP2U,0.1 μg),and their thickness uniformities were measured using a length gauge(ND280/CT2500,±0.03 μm).The results show that the material utilization rate achieves nearly 100％,the thicknesses of self-supporting metallic 150Sm and 147Sm targets are respectively 2.1 mg/cm2 and 2.3 mg/cm2,and the thickness uniformities of self-supporting metallic 150Sm and 147Sm targets within the range of 20 mm×20 mm are respectively 95.7％and 97.4％.The 150Sm/C and 147Sm/C targets were prepared by the carbon arc-rotating substrate evaporation with ultra-short source-substrate distance composite coating technique.The carbon film thickness was measured online via a quartz crystal thin-film thickness monitor(SQM-160).The effect of evaporation current on the surface quality of the targets was studied by scanning electron microscope(SEM).The results show that the target deposited with an evaporation current of 75-80 A has a better surface finish,no obvious defects or droplets,the thicknesses of the 150Sm and 147Sm targets on the carbon substrates with 25 μg/cm2 are respectively 255 μg/cm2 and 267 μg/cm2,and the material utilization rates achieve respectively 7.19％and 7.32％.