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

Major parts of our proven calibration facility have been totally renewed and other equipment has been added to fulfill the actual requirements for efficient calibration of modern space ion mass spectrometers. The 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 precision. An additional effort has been made to design and test a new expansion system with higher transmission and improved quality with respect to overall homogeneity, parallel trajectories, and angular divergence of the ion beam. A personal computer is used to survey the state of the whole vacuum system permanently and to vent, pump down, and bakeout the calibration chamber automatically. A main computer has been installed which controls the turntable, the ion beam, the beam diagnostics, experimental high voltages, and the data acquisition with our detectors. 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 spectrograph instrument for the POLAR mission is described. (C) 1995 American Institute of Physics.