Broadband time-resolved elliptical crystal spectrometer for X-ray spectroscopic measurements in laser-produced plasmas

• Published in: Chinese physics B Vol. 23; no. 11; pp. 257 - 260
• Main Author: 王瑞荣 贾果 方智恒 王伟 孟祥富 谢志勇 张帆
• Format: Journal Article
• Language: English
• Published: 01.11.2014
• Subjects: Crystals; Lasers; Plasmas; Spectra; Spectral resolution; Spectrometers; Streak cameras; Titanium; X-rays; X射线光谱仪; 光谱测量; 时间分辨光谱; 晶体; 椭圆形; 激光产生; 等离子体; 高能量密度
• DOI: 10.1088/1674-1056/23/11/113201
• ISSN: 1674-1056

The X-ray spectrometer used in high-energy-density plasma experiments generally requires both broad X-ray energy coverage and high temporal, spatial, and spectral resolutions for overcoming the difficulties imposed by the X-ray back- ground, debris, and mechanical shocks. By using an elliptical crystal together with a streak camera, we resolve this issue at the SG-II laser facility. The carefully designed elliptical crystal has a broad spectral coverage with high resolution, strong rejection of the diffuse and/or fluorescent background radiation, and negligible source broadening for extended sources. The spectra that are Bragg reflected （23° 〈 θ 〈 38°） from the crystal are focused onto a streak camera slit 18 mm long and about 80 μm wide, to obtain a time-resolved spectrum. With experimental measurements, we demonstrate that the quartz（1011） elliptical analyzer at the SG-II laser facility has a single-shot spectral range of （4.64-6.45） keV, a typical spectral resolution of E/△E = 560, and an enhanced focusing power in the spectral dimension. For titanium （Ti） data, the lines of interest show a distribution as a function of time and the temporal variations of the He-α and Li-like Ti satellite lines and their spatial profiles show intensity peak red shifts. The spectrometer sensitivity is illustrated with a temporal resolution of better than 25 ps, which satisfies the near-term requirements of high-energy-density physics experiments.