Determination of Atomic Number Densities of 87Rb and 3He Based on Absorption Spectroscopy

The atomic number densities of Rb-87 vapor and surrounding gas He-3 in a sealed cubic cell were measured by sweeping the absorption line and fitting the experimental data with a Lorentzian profile. The absorption was carried out around the D1 transition at different temperatures. We compare our results for the number density for(87) Rb with the previous methods and calculate the fractional error to be less than 5% as well as the error for He-3 between this work and the density obtained from the filling procedure to be no more than 4.2% at 370 K. In addition, we discuss the factors that contribute to the error, among which the cell temperature plays the most important role.