An advanced laboratory in nuclear-isotope mass spectroscopy

We describe an experiment in nuclear-isotope mass spectroscopy, suitable for an advanced physics laboratory, which utilizes a relatively inexpensive commercial 60°-dipole residual gas analyzer. Students measure the terrestrial abundance of the isotope $Ne22$ relative to $Ne20$ and compare this with recent measurements of this ratio in meteorites. These ratios provide clues to the astrophysical sites, astrophysical processes, and nuclear reactions which formed these isotopes. The mass spectrometer is also used as a residual gas analyzer to examine the gas composition (⁠$O2,$ $N2,$ $H2O,…$⁠) at various pressures in a typical vacuum system. This gives students insight into the design of vacuum apparatus including the optimal selection of components such as vacuum pumps for particular applications.