A MODERN AND FULLY AUTOMATED CALIBRATION SYSTEM FOR SPACE ION MASS SPECTROMETERS

Major parts of our proven calibration facility have been totally renew ed and other equipment has been added to fulfill the actual requiremen ts for efficient calibration of modern space ion mass spectrometers. T he main change was the replacement of the old two axes turntable by a new four axes turntable that can be used in a wide range with high pre cision. An additional effort has been made to design and test a new ex pansion system with higher transmission and improved quality with resp ect to overall homogeneity, parallel trajectories, and angular diverge nce of the ion beam. A personal computer is used to survey the state o f the whole vacuum system permanently and to vent, pump down, and bake out the calibration chamber automatically. A main computer has been in stalled which controls the turntable, the ion beam, the beam diagnosti cs, experimental high voltages, and the data acquisition with our dete ctors. A general interface allows the full control of the whole system for the complete automated calibration of a flight instrument. As an example, the calibration of the toroidal imaging mass-angle spectrogra ph instrument for the POLAR mission is described. (C) 1995 American In stitute of Physics.