Soft X-Ray Time-Resolved Unfolded Spectrum For Studying Laser-Produced Plasmas

Since the introduction of high-power short-pluse lasers well, there has developed a strong interest in the high-density high-temperature plasmas produced by the interaction of intense laser light with matter. Despite these laser-produced plasmas are small-size(~100urn)and short-lived, with parameters changing on the scale of tens to hundreds of picoseconds, they have quite important science and practical effect. Measuring X-ray energy-spectrum emitted by these laser-produced plasmas is a important diagnose method, because they emit a mass of X-ray. Now the method has application at large. Because the laser-produced plasmas are rapidly varying, temporal resolution of spectral features is important to investigation of X-ray radiancy evolvement with time, many dynamic plasma processes and radiation transport. Soft X-ray time-resolved diagnosis technology have had quiet great progress since from sixty' s end to seventy' s early. Take a photograph of devices hav developed from Dante spectrometer to soft X-ray streak camera(At~20ps) in which one has a chance to investigate a good many plasma phenomenon. Measurement of the time-varying spectral shape of the soft X-ray continuum from laser-fusion targets can provide a detailed dynamical record of X-ray processes important to the understanding of thermal conditions in such experiments. Observation of the on-off sequencing of characteristic spectral lines from tracer materials arranged in layers in, or surface patterns on, planar or spherical targets can provide a record of radial or lateral energy transport processes in laser-generated plasmas. In addition, the temporal evolution of detailed spectral feature (such as linewidthand line shape)can provide important information about ablation dynamics and perhaps target compression in laser-fusion studies.Now a very interesting time-resolved X-ray spectrometer, in which an transmission grating is coupled with a X-ray streak camera has been a X-ray spectrograph. The device has excellent spectral (??1 ) and temporal (?t~20ps). And it has a wide spectral range(0.1 ?10keV), high sensitivity and a large information recording capacity. The photographic data record of the transmission grating spectrometer is a 2-D representation of X-ray spectrum (wave length vs time). Although the data record contains all the essential information about the desired source spectrum, that information is folded together with details of the instrument response. So one must carry thought unfolded work.Using transmission grating spectrometer to measure soft X-ray in 2001sheng-guangII experiment. Time-resolved spectrum has temporal resolution ?t~20ps. In (the streak cameraoutput distribution function, see text), we have unfolded successfully the X-raysource spectrum with repeatedly et al mathematics way.