| 摘要 |
PURPOSE:To enable exact and easy measurement of mass number and effective use of a computer in the stage of adjusting mass marker determining the mol. wt. of material by providing a voltage scanning means which scans the voltage to be impressed to a detector and scanning the voltage impressed to the detector in parallel with mass scanning. CONSTITUTION:The secondary ion generated in an ion source part 2 enters an analysis part 6. A mass number parameter is scanned with time by a control means 8 for the analysis part in the part 6 by which the secondary ion is mass- separated and is put into a detector 10. The voltage impressed to a detector 10 is scanned in parallel with the scanning of the mass number parameter in the part 6 by a voltage scanning means 12. Since the acceleration voltage of secondary electron is changed by such scanning, the gain of the detector 10 is eventually scanned and the detecting sensitivity is increased with an increase in the mass number. The threshold value HT for whether the signal outputted from an amplification part 14 is arithmetically processed or not is simultaneously scanned with time in a CPU18. The noise signal component arising with an increase in the gain of the detector 10 is thus removed. |
