= Ruby pressure scale
{title2=$\Delta\lambda=\lambda_{R_1}-\lambda_{R_1,0}$}
{wiki}
= Ruby fluorescence pressure calibration
{synonym}
The <ruby pressure scale> converts a shift of a <ruby> <fluorescence> <spectral line> into <pressure>. Excitation <light> produces a <fluorescence emission spectrum>; fitting its $R_1$ line gives a <wavelength> $\lambda_{R_1}$. The reference $\lambda_{R_1,0}$ must be measured or assigned at specified reference <pressure> and <temperature>. The difference $\Delta\lambda$ is an observable; interpreting it as <pressure> requires a <pressure calibration> and suitable <stress> conditions.
The original 1972 report found sharp $R_1,R_2$ emission shifting toward lower <photon> <energy> as <pressure> increased; it tentatively associated broadening with nonhydrostatic conditions.<Pressure Measurement Made by the Utilization of Ruby Sharp-Line Luminescence by Richard A. Forman and others>[Abstract: direction of R-line shifts and tentative nonhydrostatic interpretation]{ref} In use, excitation rejection, a calibrated <wavelength> axis and a fitted background matter because leakage or background can move an apparent peak. A brighter trace improves counting statistics but does not alone establish a correct <pressure> scale.
Back to article page
