  A study of Helium-Neon laser plasma lines was done using a double grating
spectrometer and a He-Ne laser with an emission wavelength of 632.8 nm (15,802
cm$^{-1}$). The absolute wavenumber, measured to within $\sim0.1$ cm$^{-1}$,
and wavelength of each plasma line are presented, along with intensity and
shift relative to the main laser line. Several of the measured lines have not
been reported in the literature and are observed at shifts between $0-1500$
cm$^{-1}$ from the laser line, a spectral region commonly probed by optical
Raman scattering experiments. Accounting for the possibility of second-order
diffraction permitted many previously unassigned lines to be attributed to
known He or Ne electronic transitions with wavelengths in the ultraviolet
region of the electromagnetic spectrum.
