激光银等离子体XUV谱测量

THE XUV SPECTRA OF LASER-PRODUCED Ag PLASMA

用１ｍ掠入射光栅谱仪测量了入射激光功率密度为３～６ＴＷ／ｃｍ￣２时，块状银靶产生的等离子体ＸＵＶ光谱。对４～１１ｎｍ波长范围内的谱线进行辨认和分类。

AbstractThe experiments are carried out at“Xingguang”laser fascility.The laser is Nd:glass sys-tem with a wavelength of 1.06μm. Laser pulse duration(FWHM)is about 600ps,with 3～10Jdelivered to a target in a point focus.A1-meter grazing incidence spectrograph with 1200lines/mm is plased at the position 40mm from the target to photographed time-integrated XUVspectram Its entrance slit with 10μm in width is horizontally oriented parallel to the incidentlaser axis. The XUV spectra emitted from the laser-produced plasma are recorded on Kodak SWRfilm. Three shots are used for a spectrum. Reference spectra consisted of lines of C￣(4+),C￣(5+),O￣(6+)and O￣(7+) originating in a formvar film target. The spectra due to transitions in Ag ⅩⅦ～AgⅩⅩⅡ are present.In order to identify thespectral lines,the energies, spontaneous decay rates and oscillator strengths of the transitionsare computed with the help of Cowan’s HFR program. When the targets are irradiated withthe Dower density of 3～6TW/cm￣2,the spectrum obtained is dominted by the trasitions in AgⅩⅠⅩand AgⅩⅦ. The principal lines of AgⅩⅦ～AgⅩⅠⅩ corresponded to the transitions from n=5tO 4. For AgⅩⅩⅠ～AgⅩⅩⅡ, the principal lines are due to transitions from n=3 to 3.