Authors: Simeonov, L.I.
Reference: Comp.Rend.Acad.bulg.Sci., 43, 8, 47-50, 1990.
The implementation of carbon foil (CF) time-of-flight (TOF) energy and mass analyzers in space mass spectrometry has shown an increasing progress in the last years. This is due to the introduction of new concepts of design, such as the time and space focusing of the investigated particles in a retarding field, situated behind the CF, in the so-called reflection. As a result, a very high mass resolution is achieved along with considerable widening of the mass range, reduction of the accelerating high voltage and the thickness of the CF itself. In the process of design it is essential to know the exact quantitative dependence of the energy losses and the angle deflections on the CF target thickness, in order to evaluate the restraints, which they put on the technical and physical parameters of the analyzers. These restraints are associated with the maximum energetic and angle dispersion at which an analyzer operates within the desired mass and energy resolution. In the paper are presented graphically results from a computer simulation of the interaction of ion fluxes of 1000 particles of the elements H, He, Li, O, Mg and Ag with initial energy of 20 KeV with a CF target with thickness in the range 10 ÷ 70 Å. Presented are calculations of the transition coefficient, the mean energy of the ion fluxes after passing of the foil, the energetic distributions after the foil target and the mean angle of escape. The MARLOWE simulation program, which was used, is appropriate for modeling of the interaction ion-solid body in the lower energetic range up to 20 KeV. The energetic range and the CF thickness were chosen for the purposes of design, laboratory test and calibration of a linear CF TOF reflection, prepared for space research implementation.