Research of the capillary target-ion source system in on-line experiment

In order to study new isotopes and nuclear decay, properties in the A > 170 mass region, the laser ion source is needed and developed. For on-line iso tope separator. it is required that the capillary ionization has a speciali ty, of low hot ionization efficiency and high ion extraction efficiency. Th e principle of the hot capillary ionization was described. The employment o f Nb capillary reduces the temperature for forming the plasma potential and inhibitory hot ionization. The ionization tube is made of a Nb capillary o f 2.2mm outside diameter, 1.7mm inside diameter and 30mm effective length. The temperature is 1600-2500K when the current is 40-100A. The target chamb er is structured by Ta tube of 0.1mm wall thickness and windows of 6 mum Ta foil at two ends. Its maximum temperature is 2200K with the current 300A. The test experiment with on-line conditions at isotope separator ISOLAND ha s been performed. Yb-167 ( T-1/2 = 17.5min) isotope was produced in nuclear reaction O-18 (50MeV/u) + Ta-nat --> Yb-167. In the condition of target ch amber temperature 2130K and capillary temperature 2130K, the total efficien cy is 0.2%, This target-ion source system will be satisfied in laser ion so urce.