| 摘要 |
PURPOSE:To enable to remove background ions and to detect ions of a very small quantity of sample with a good S/N, by furnishing slits in front of and at the rear of a quadruple pole lens. CONSTITUTION:Although ions to be detected pass through around the center of the ion optical axis, ions other than those are deflected out of the axis by a magnetic field, to enter a quadruple pole lens 4, and some may reach a collector after hitting the gas or hitting and reflecting at an electric field electrode. To remove such ions, a slit is formed to control the ions entering the quadruple poles 4 to limit ions to the ions close to the axis, and another slit is also formed at the outlet side to limit the output ions to the ions close to the axis. The positions of these slits are not at the focusing point of the ion beams, but only the incident ions to the quadruple pole lens at a restricted angle can pass through the two slits. Therefore, ions to cause a scattering or other backgrounds can be removed. |
