摘要:
In a vacuum system a baffle-valve acts first as a baffle to reduce the backstreaming of a diffusion pump fluid into the main vacuum chamber being evacuated and secondly it can be used as a valve to provide complete isolation between the diffusion pump and the vacuum chamber. This enables the chamber to be open for service work while the diffusion pump is kept operating for rapid pump down. The foregoing dual use of the baffle/valve increases pumping efficiency because of higher conductance.
摘要:
In a mass spectrometer a focusing ion lens system effectively separates charged from neutral particles by forming a potential well along the axis from the ionizing region to the mass analyzer by the use of a gridded lens system. The grids by the use of a high-low voltage combination form the potential well while at the same time allowing nonselected neutral particles to pass through the grid. Thus, the system is very effective for relatively high pressure ionizing regions where a large amount of neutral particles are generated.
摘要:
Apparatus and method for programming the ion energy of ions being analyzed by a quadruple mass spectrometer where the axis potential applied to the quadruple rods is caused to vary in synchronism with a mass scan in order that the ions of each mass being analyzed may transit the quadruple with the most advantageous energy for proper analysis (that is, with substantially equal velocities) and the application of the ion scan voltage will not distort the fringing field at the entrance to the quadrupole.
摘要:
A method of selecting a material for the construction of a multipole mass filter that is temperature stable or in other words, the R.sub.o parameter remains invariant with change in temperature. The coefficients of thermal expansion of the quadrupole rods and mounting structure are chosen so that a constant ratio of the two is provided which in turn is determined by the geometrical construction of the filter.