Fig. 3

The Okazaki large spectrograph (OLS). (a) Layout of the OLS room (modified from [32]). A, monochromator room; B, irradiation room; C, sample preparation room; D, staff room; E, power supply room. A1, 30 kW xenon lamp; A2, rotatable condensing mirror; A3, shutter; A4, the heat-absorbing filter; A5, entrance slit; A6, plane mirror; A7, condensing mirror (110 × 110 cm, curvature radius of 9 m); A8, double-blazed plane grating (90 × 90 cm); A9, window; B1, focal curve stage; C1, incubators. Basically, the monochromatic lights are radially and horizontally irradiated from A8 to B1 where the OMR tests were performed. (b) The actual monochromatic lights irradiated in the OLS room. Plastic boxes were placed on the focal curve stage (bottom). The window (top right) is fully opened and all other lights in the OLS room were turned off. The light from the xenon lamp was thus dispersed into a contiguous spectrum from λ = 250 nm to λ = 1,000 nm. The intensities of the monochromatic lights at representative wavelengths are shown in Table 1