Investigation Of The Extreme Ultraviolet Radiation Properties And Wavelength Calibration Of Laser-produced Plasmas

Laser-produced plasma?LPP?,formed by focusing nanosecond pulsed laser onto solid sample target,has the characteristics of intense burst of radiation over a broad spectral range,coexistence of various charge state ions,complex atomic process and the spatial gradient of temperature and density is larger.A high-resolution EUV spectrograph is an indispensable tool to study radiation and dynamic properties of laser produced plasma.In the study of this thesis,we completed the wavelength calibration of the Mcpherson 248/310G grazing incidence high-precision UV spectrograph using the EUV spectra of laser produced Al,C,Si and S plasmas.Combined with the obtained calibration data and atomic structure calculation program,the radiation characteristics of laser produced Cr plasma in the extreme ultraviolet region are deeply studied,and a large number of energy levels and transition information are obtained.These information can be further applied to spectrograph calibration.The main works of this thesis are as follows:?1?The EUV spectra of laser produced Al,C,Si and S plasma at the central wavelengths of 9.5 nm,10 nm and 12 nm were measured,and the spectral lines were identified.Using the identified spectral data and polynomial fitting,the wavelength calibration of the spectrograph under the above three central wavelengths was completed.?2?Laser produced Cr plasma spectra at 6.5-15 nm band were measured in the experiment,and wavelength conversion was carried out using the calibration data obtained.Based on the atomic structure calculation program FAC and Cowan RCN,RCN2 and RCG,it is identified that the experimental spectra mainly come from the 3p-4d,5d and 4s transitions of Cr⁵⁺-Cr¹⁰⁺ions.It was confirmed that the spectral lines of six highly charged ions can be used in wavelength calibration of spectrograph.The experimental spectra were simulated by combining transition information,charge state distribution and level population information.The plasma temperature and electron density were obtained,and the state diagnosis of laser Cr plasma was completed.