Table 12.

Propagation of Raman photons from source to detector for gypsum ${\nu }_1$ emission

Distance (m)	At source	At aperture	At cathode
1.8	1.8e7	4820	310
2.3	4.0e7	4080	260
2.8	7.5e7	3480	220
3.3	1.0e8	2400	150
3.8	1.3e8	1710	110
4.3	1.3e8	1080	68
4.8	1.3e8	690	43
6.0	1.1e8	250	14

Units are photons between the FWHM of the Raman peak per laser pulse. For the source emission, only photons produced within the spectrometer FOV are counted (as in Fig. 49), resulting in an increase between 1.8 and 3.8 m. Numbers are based on measurements made with the EQM. The FM will have different results based on alignment at the time of measurement