| Measurement of soft X-ray energy spectrum is an important part in ICF experiments. With spectrum analysis, soft X-ray diagnosis can get total flux of X-ray, radiation temperature, conversion efficiency and albedo, which are important parameters of indirect drive hohlraum thermodynamics. As a hohlraum character diagnostic system, the soft X-ray diagnostic system can measure X-ray radiated by hohlraum and give radiation temperature vs. time curve. However, at present various spectrometers being used have some disadvantages, such as low energy spectrum resolving power, difficult unfolding method and so on. In order to avoid those shortcomings and make measurement more efficient and more precise, a multi-layer soft X-ray spectrometer (MLSXS) has been studied and developed.On the base of ICF experiments'particular requirements for soft X-ray diagnosis and the features of multilayer, this paper studies and analyzes the operating principle, executable programs and several key technical units about vested spectrometers. Then high temperature plasma X-ray diagnostic techniques are introduced. And the paper illuminated the system structure and principle of work on MLSXS, completed the physical design about spectrometer's eight channels. At the same time, the mechanical structure of MLSX is designed. The 3-D spectrometer mode is built and analyzed by modern finite element techniques (FET). At last the reflectivity of multi-layers is calibrated. The main content as follows:①The paper introduces all kinds of diagnostic methods, the principle and development of multi-layer. On the base of analyzing the features and requirements of X-ray diagnosis, operating principle and structure of MLSXS are showed.②Combining the requirements for the spectrometer in diagnosis experiments, the MLSX scheme is proposed. The spectrometer has eight channels that consist of multi-layer mirrors, filters and X-ray diodes (XRDs). The energy range is 0.1～1.5keV. Energy resolution (E/?E) should be higher than 15. The uncertain of multi-layers'angle has to be better than 2%.③By analyzing the principle, design methods and manufacture techniques, the parameters design of multi-layers and filters is accomplished. And the results about multi-layer reflectivity and filter transmission efficiency are calculated. Then the paper gets eight channels'theoretical response functions of MLSXS. ④Along with the scheme, the mechanical structure of MLSX is designed. And the 3-D mode is built by Pro/E. Then the paper makes use of the FEA software Ansys10.0 to implement the static and modal analysis. As a result, the optimization results are gained.⑤Beijing synchrotron radiation facility (BSRF)-3W1B beam line was used to conduct experiments on the multilayer mirror reflectance calibration. The reflectivity calibration curves for 21°-B4C/Si, 21°-B4C /Mo, 14.93°-C/Cr, 10°-Cr/Ti, 15°-B4C/W, 10°-B4C/W,6.86°-B4C/W multilayer mirrors are given, in the calibration region of 50 eV～1 500 eV. And the values of experiment and calculation are compared and analyzed. Results show that performances of them satisfy the design and use requirements. Using those data, the channels'real response functions are given, which are data guarantee for MLSXS application in X-ray measurement.Adopting multi-layer as diffraction element and combing filter's absorbency, eight channels soft X-ray spectrometer can perform its expected function successfully. Those key technique units are proved with high reliability, accuracy and stability. The performances of MLSXS include:①Energy scale: 95eV～1450 eV (95eV,175 eV,260 eV,420 eV,650 eV800 eV,1000 eV,1450 eV);②Adjusting performance of multi-layer:±3.4°in angle adjuting, and±16mm in level moving;③Collimation angle uncertainty:<1.5%;④Energy resolution E/ΔE:≥5。The performances of MLSXS satisfy the requirements well except energy resolution. And the study provides some valuable references for further research. |
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