| 摘要 |
PURPOSE:To enable the reflux of cooling water to an ion source and fully exhibit easiness of obtaining the information of molecular weight that is an advantage of a chemical ionization method by applying the potential that corresponds to ion accleration voltage to an injection slit and an analytical section so as to set the ion source to ground potential. CONSTITUTION:Gas such as methane, isobutane, and ammonia for ionization reaction is supplied to an ionization chamber 11 from a reagent gas supply port 5 and this reagent gas is changed into an ion due to electron bombardment and ion molecular reaction by making an electron generated from a hot cathode 7 incident from an electron incident hole 6 to this gas. In addition, the induced sample gas is ionized when this ion reacts with the sample gas. In this case, since the potential that corresponds to the ion pressurized voltage is applied to an injection slit 2 and an analytical section 3 from a power supply 4, an ion source 1 is set to ground potential E and the reflux of cooling water is enabled. As a result, the temperature of the ion source can be reduced by making the cooling water flow back from an entrance 9 to the ionization chamber 11 and to an exit 10. |
