Dietz L A, Hanrahan L R
General Electric Company, Knolls Atomic Power Laboratory, Schenectady, New York 12301.
Rev Sci Instrum. 1978 Sep;49(9):1250. doi: 10.1063/1.1135590.
A general-purpose ion detector has been developed for fast pulse counting in mass spectrometry. It consists of a six-stage electron multiplier joined to part of a scintillator detector. This novel arrangement combines the virtually noiseless pulse-amplification response of an electron multiplier with the bipolar voltage flexibility of a scintillator detector. The resulting hybrid detector is superior in performance to either an electron multiplier or a conventional scintillator detector. It is designed to detect a beam of positive ions or negative ions focused to a line image or to a spot at the focal plane of a mass analyzer. Background counting noise is less than 1 count/min when the detector is used in either the positive ion or negative ion detecting mode. Mass-resolved ions are post-accelerated through an electric field to give them an additional kinetic energy of 10 keV before they strike the ion-to-electron converter in the electron multiplier. This allows low-energy ions to be detected with an efficiency close to unity, over a range of ion masses from 1 amu up to several hundred amu. Randomly spaced pulses can be counted at rates from 0 Hz to 10 MHz. The design of the detector and its operating characteristics are discussed.
已开发出一种用于质谱中快速脉冲计数的通用离子探测器。它由一个六级电子倍增器与部分闪烁体探测器相连组成。这种新颖的配置将电子倍增器几乎无噪声的脉冲放大响应与闪烁体探测器的双极电压灵活性结合在一起。由此产生的混合探测器在性能上优于电子倍增器或传统的闪烁体探测器。它旨在检测聚焦成线图像或聚焦在质量分析器焦平面上的点的正离子束或负离子束。当探测器用于正离子或负离子检测模式时，背景计数噪声小于1计数/分钟。质量分辨离子在电场中进行后加速，使其在撞击电子倍增器中的离子到电子转换器之前获得10 keV的额外动能。这使得低能量离子在1 amu到几百amu的离子质量范围内能够以接近1的效率被检测到。随机间隔的脉冲可以以0 Hz到10 MHz的速率进行计数。讨论了探测器的设计及其工作特性。
