ANALYSIS AND CALCULATION ON SPATIAL DISTRIBUTION OF MAGNETIC FIELD IN THE MINIATURE MAGNETIC SECTOR MASS SPECTROMETER

The function of the magnetic sector mass spectrometer is to resolve the ions according to their mass-to-charge ratios.Because the function of the mass spectrometer is greatly affected by the field strength of magnetic analyzer,the accurate computation of these magnetic fields is essential for realistic performance predictions at the design stage of magnetic analyzer.This paper employs the finite method to derive the calculated model on spatial magnetic field emanated from magnetic analyzer,and analyses the spatial distribution of magnetic field.It is shown that the distribution of magnetic flux density is analogous on quarter circle with the deflection radius of 20mm and 50mm.Because of the fringing magnetic field effect,the magnetic flux density almost linearly decreases on the edge of the magnet about 3mm.The result provide basis for optimizing the structure and calibrating the fringing field.