摘要 |
PURPOSE:To repeatably make high resolution measuring by simple operation on a low mass side by switching at least one of the magnitude of D.C. voltage, and the maximum value and the angular frequency of high frequency voltage. CONSTITUTION:When variables a=8eU/mr0<2>omega<2>, and q=4eV/mr0<2>omega<2> (where U: magnitude of D.C. voltage, V: maximum value of high frequency voltage, e: electric charge of ion, m: mass of ion, r0: radius of inscribed circle of rod electrode, and omega: angular frequency of high frequency voltage) are represented as a rectangular coordinate ((a and q) plane), at least one of U, V, and omega is switched in different values for the purpose of the selective use of a first stable region nearest to and a second stable region second nearest to an original point in a region where a condition, in which ions can pass a quadrupole electrode, is decided. Thus, high resolution excellent in stability and repeatability can be obtained by simple operation even if high resolution is set. |