Mielenz K D, Eckerle K L, Madden R P, Reader J
Appl Opt. 1973 Jul 1;12(7):1630-41. doi: 10.1364/AO.12.001630.
A new single beam spectrophotometer is described in which transmittance is measured by placing samples normal to a parallel beam of light. Collimation and focusing of the main beam are achieved by means of off-axis parabolic mirrors. The wavelength at which the transmittance is to be measured is selected by a plane grating monochromator having off-axis parabolic mirrors and circular holes as entrance and exit apertures. The instrument has an inherent accuracy estimated to be 0.0001 transmittance unit. Its precision is characterized by a repeatability of 0.00004 transmittance units for neutral-density filters with transmittances between 10% and 30%. The design philosophy used to achieve these results is presented. A discussion of some systematic errors commonly neglected in routine spectrophotometric, measurements is given. Systematic errors such as detector nonlinearity and stray radiant energy are measured.
本文介绍了一种新型单光束分光光度计，该仪器通过将样品垂直于平行光束放置来测量透光率。主光束的准直和聚焦通过离轴抛物面镜实现。待测透光率的波长由平面光栅单色仪选择，该单色仪的入射和出射孔径采用离轴抛物面镜和圆孔。该仪器的固有精度估计为0.0001透光率单位。对于透光率在10%至30%之间的中性密度滤光片，其精度表现为重复性为0.00004透光率单位。文中介绍了为实现这些结果所采用的设计理念。讨论了常规分光光度测量中一些通常被忽视的系统误差。测量了诸如探测器非线性和杂散辐射能等系统误差。
