| 摘要 |
PROBLEM TO BE SOLVED: To automatically decide optimum ionization energy with ease by second order differentiating an ion current obtained from scanning ionization electron energy, comparing a maximum value of the differential signal with a set value, and setting ionization energy for a neural radical. SOLUTION: In an appearance mass analyzer meter 11, ionization energy scanning on an ion source 12, in which gas and neutral radials are mixed in plasma, is carried out by means of an electron energy scanning circuit 35. A predetermined mass ion current provided in this way is fed to a second order differentiating circuit 32 via an amplifier 31 so that an ion current is second order differentiated. In this way, a second order differential signal having two maximum peaks in response to the raise in an ion current signal is provided. These maximum peaks are respectively compared with a set value by means of comparators 33, 33a, and a point, in which the maximum peak exceeds the set value, is detected. On the basis of this detection value, energy in the middle of both detection values is outputted as an optimum ionization energy value in a neutral radical measurement time to the energy scanning circuit 35 by means of a signal processing unit 34.
|
