公开(公告)号：US3742212A

公开(公告)日：1973-06-26

申请号：US3742212D

申请日：1971-02-16

Applicant: UNIV LELAND STANFORD JUNIOR

Inventor： MC IVER R

IPC: G01R33/64 ,  H01J49/38 ,  B01D59/44

CPC classification number: H01J49/38 ,  G01R33/64

Abstract: A method and apparatus for pulsed ion cyclotron resonance spectroscopy is disclosed in which a gas sample within an analyzer cell is ionized by means such as a pulse of an electron beam. The ions are subjected to a combined action of a plurality of static electric fields and a magnetic field thereby trapping the ions and causing them to move orbitally within the cell. Following ionization by said pulse of an electron beam and after a reaction time delay period, ions of a given charge-to-mass ratio are brought into resonance with an oscillating electric field applied transversely to the lines of force of the magnetic field. During such detection period those ions in resonance with the oscillating electric field absorb energy therefrom, which absorbed energy is detected as a measure of the resonant ions. The ions are then swept from the cell. By use of oscillating electric fields of different frequencies for resonance with ions of different charge-to-mass ratio the arrangement serves a mass spectrometer function. For ion-molecule reaction studies the above described cycle is repeated but with different reaction time delay periods whereby the concentration of the resonant ions at different times during the course of reaction is determined. From this, the thermal rate constant for such ion-molecule reaction is readily determined. The method and apparatus of this invention are readily adapted for double resonance mass spectroscopy. By irradiating the ions with a pulsed radio frequency electric field at a second frequency, ions of a given charge-to-mass ratio may be accelerated to high velocity, yet still remain trapped within the analyzer cell. As above, after a reaction time delay period following said radio frequency pulse, ions of a given charge-tomass ratio are brought into resonance with the first mentioned oscillating electric field to obtain a measure of such ions. Also as above, this double resonance cycle may be repeated with different reaction time delay periods. By this means the thermal rate constant for the reaction as a function of the kinetic energy of the ions accelerated by the pulsed radio frequency electric field at the second frequency is readily determined. The spectrometer includes a novel analyzer cell within which ions may be trapped for long periods of time on the order of 100 milliseconds, or greater. The cell includes a hollow electrode array comprising first, second and third pairs of opposite plates. A trapping potential of one polarity is applied to the one pair of opposite plates, and an opposite polarity trapping potential is applied the other two pair of opposite plates to provide an electrostatic potential well within the cell for trapping the ions for extended periods. Various experiments requiring extended ion trapping periods are possible utilizing the novel ion trap.

Abstract translation: 公开了一种用于脉冲离子回旋共振光谱的方法和装置，其中分析器单元内的气体样品通过诸如电子束的脉冲的方式被电离。 离子受到多个静电场和磁场的组合作用，从而捕获离子并使它们在电池内轨道移动。 在通过电子束的所述脉冲进行电离之后，在反应时间延迟周期之后，给定电荷质量比的离子与横向于磁场的力线施加的振荡电场共振。 在这种检测期间，与振荡电场共振的那些离子从其中吸收能量，这被吸收的能量作为谐振离子的量度被检测。 然后离子从细胞扫过。 通过使用不同频率的振荡电场与不同电荷质量比的离子共振，该装置用于质谱仪功能。 对于离子 - 分子反应研究，重复上述循环，但是具有不同的反应时间延迟时间，由此确定在反应过程中不同时间的共振离子的浓度。 由此可以容易地确定这种离子 - 分子反应的热速率常数。