Molecular beam system controlled by quadrupole mass spectrometer

Abstract
A molecular beam epitaxy (MBE) apparatus is described in which some improvements over earlier systems have been achieved. An isolation valve permits the introduction of samples without disturbing the ultra-high vacuum system. The beam fluxes are controlled by a quadrupole mass spectrometer; by this means beams of gallium and arsenic can be kept constant to within 1 and 3% respectively.