The elliptical bent crystal spectrometer (EBCS) is coupled to X-ray CCD

and a set of system (EBCS-XCCD) for measuring X-ray spectra is briefly described. The unique advantages of the elliptical crystal spectrometer for precise and absolute spectral measurement are noted. The X-ray spectrum from the laser-produced plasma has first been measured by the EBCS-XCCD on the "ShenGuang II" Facility. In order to obtain truly experimental results

an originally spectral photograph measured by the EBCS-XCCD must be calibrated. The calibration procedures for absolute line and line intensity measurement are studied and formulae of identification signal are deduced according to the geometrical parameter of the EBCS-XCCD and physical optics. The example of calibrating spectra is presented as measured with elliptical crystal of α-quartz （1010，2d = 0.852 nm ) for the 0.399 — 0.736 nm photon wavelength region. The intensity of spectrum from laser plasma X-ray source is also obtained by the formula

based on known the integrated reflectivity of the crystal

the transmission of the foil which blocks out visible and ultraviolet (UV) portions of the spectrum

and the responsivity of X-ray CCD photodiode to photons. The spectra of Al laser-produced plasma and good spectral resolution better than 1000 are shown. The unfolded spectra by the method are compared with that of the reference [1]. Their results are basically identical. It is shown that the instrument is particularly suitable for high-precision measurements of the spectral line profiles and positions in nonhomogeneous plasmas. The examples of experimental results

which are superior to those obtained in earlier measurements

demonstrate the EBCS-XCCD performance and suggest a broad field of possible application.