Key points are not available for this paper at this time.
The efficiency of a Raman tube for gases can be increased by multiple reflections from concave mirrors. With a four-mirror arrangement, the intensity of the scattered light entering the spectrograph is increased by the factor 1/(1−R), where R is the reflectivity of the mirrors. A two-mirror Raman tube is described, which gave a nearly fourfold increase in intensity in the ultraviolet.
Welsh et al. (Mon,) studied this question.