Bell Ronald E, Scotti Filippo
Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
Rev Sci Instrum. 2010 Oct;81(10):10D731. doi: 10.1063/1.3485096.
A scanning visible spectrometer has been prototyped to complement fixed-wavelength transmission grating spectrometers for charge exchange recombination spectroscopy. Fast f/1.8 200 mm commercial lenses are used with a large 2160 mm(-1) grating for high throughput. A stepping-motor controlled sine drive positions the grating, which is mounted on a precision rotary table. A high-resolution optical encoder on the grating stage allows the grating angle to be measured with an absolute accuracy of 0.075 arc sec, corresponding to a wavelength error ≤0.005 Å. At this precision, changes in grating groove density due to thermal expansion and variations in the refractive index of air are important. An automated calibration procedure determines all the relevant spectrometer parameters to high accuracy. Changes in bulk grating temperature, atmospheric temperature, and pressure are monitored between the time of calibration and the time of measurement to ensure a persistent wavelength calibration.
已制作出一台扫描可见光谱仪，作为固定波长透射光栅光谱仪的补充，用于电荷交换复合光谱分析。采用快速f/1.8、200毫米的商用镜头搭配一块大尺寸的2160毫米⁻¹光栅，以实现高吞吐量。一个由步进电机控制的正弦驱动器用于定位安装在精密旋转台上的光栅。光栅平台上的高分辨率光学编码器能够以0.075角秒的绝对精度测量光栅角度，这对应于波长误差≤0.005埃。在此精度下，由于热膨胀导致的光栅槽密度变化以及空气折射率的变化都很重要。一种自动校准程序能够高精度地确定所有相关的光谱仪参数。在校准时间和测量时间之间监测光栅整体温度、大气温度和压力的变化，以确保波长校准的持续性。
