The soft X-ray emission in cylindrical Mo and Al cavity targets with diameter and depth between 0.5 and 1.5 mm, irradiated with 12 J, 13.3 ns Iodine laser, was investigated. and the result was compared with that of a plane target. The best focusing position of laser beam on the target surface was found to be in 1.2mm interval by measuring the crater size produced by laser beam. Also the size of Mo plasma was measured to be 210μm. The soft X-ray emission in cavity targets was about 2 times bigger than that of a plane target. This result was explained by the plasma confinement effect in cavity target.
