JPS60165033A - Split ion analyzing device by collision activation - Google Patents

Abstract

PURPOSE:To improve detection sensibility of CA ions by making an electric field for energy analysis into a toroidal electric field while arranging a collision chamber adjacent to the ion incident end surface of the electric field for energy analysis. CONSTITUTION:A sample is ionized at an ion source IS and the ions generated here are subjected to a mass spectrograph in a magnetic field B, while the ions having the specific mass to be determined by the ion acceleration voltage and the intensity of the magnetic field B process into a collision chamber CC for being splitted here colliding with the neutral collision gas molecules, while the splitted ions processed into the electric field E for energy analysis to be subjected to energy analysis. Since the ion having a speed component in the vertical direction to the central ion orbit surface is also given the focusing power by making the electric field E for energy analysis into the toroidal electric field and the collision chamber is arranged nearing the incident end surface of the electric field E for energy analysis, the CA ions having a speed component in the orthogonal direction to the central ion orbit being incident from the collision chamber can be made to efficiently proceed into the electric field for energy analysis.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is applied to the so-called M I K E S (Ma8s-ana Yuyzedf
fion Kinetic Energy Spect
The present invention relates to an apparatus for measuring rum).

When a parent ion (C parent ion) is dropped, the parent ion cleaves into a flying core, a key ion, and a neutral molecule N. Buko + chichi → ni ten N. By investigating the state of such cleavage, useful information can be obtained for the structure of ions and the qualitative and quantitative determination of mixtures. The above-mentioned measurement utilizes the fact that primary ions generated by ionizing a sample spontaneously cleave due to the internal energy they initially possessed. Collision of molecules activates -order ions (Collision Acti
There is an analysis method in which the cleavage ion is measured by cutting and cleavage. This useless analyzer has a mass spectrometry section and an energy analysis section, and the mass spectrometer separates the primary ions generated by ionizing the sample to select one type of ion, and the selected ions are combined with gas molecules. The energy spectrum is measured by colliding the ions and making the generated cleavage ions enter the energy analyzer.

The mass of the ion (parent ion from the perspective of the cleavage ion) just ejected from the mass spectrometer is M1 velocity = ml, the mass of + is ml for the cleavage generated by the cleavage, and the mass of the neutral molecule N. When is m2, the velocity of + and N produced by cleavage is also ■
, and the energy of each movement is Am1V2. Bm2V2 2 2 . Therefore, by performing energy analysis of the cleavage ions in the energy analysis section, the cleavage ions can be distinguished by mass and the ion species can be analyzed.

The conventional device for measuring CA ions as described above is a double-focusing mass spectrometer that combines an electric field for energy analysis and a magnetic field for mass analysis, with the ion flight direction reversed, in order to obtain a high-resolution mass spectrum. The device has a configuration in which a collision chamber is arranged in which a collision gas is introduced at an ion convergence point between the magnetic field and the electric field. However, in the ch ion measurement method, parent ions and colliding gas molecules are collided, so the ion beam is scattered by the collision, and the CA ion beam is a divergent beam. On the other hand, in the conventional OA ion measuring device, the ion energy analysis section is composed of a cylindrical electric field, and has the function of converging ions of the same energy moving within the orbital plane of the central ion trajectory of the ion beam to a single point. However, the CA ions emitted from the collision chamber have a velocity component not only in the ion orbital plane but also in a direction perpendicular to the same plane, and such CA ions are not focused on the exit slit of the energy analyzer. , the detection sensitivity of CA ions was low. In addition, since the CA ions form a divergent beam, the incidence efficiency into the energy analysis section is low.
This also led to a decrease in sensitivity.

Purpose The present invention aims to solve the above-mentioned problems in conventional CA ion measuring devices.

2. In a configuration similar to that of a collision chamber placed on the ion orbit between the configuration and the electric field, the electric field for energy analysis is used as a toroidal electric field, and the C
In addition to making it possible to converge A ions, the collision chamber is placed close to the ion incidence end face of the electric field for energy analysis, in order to improve the incidence efficiency of the diverging ion beam into the electric field for energy analysis. be.

E. Example The figure shows an example of the present invention. ■E+ is the ion source, B is the magnetic field for mass spectrometry, E is the toroidal electric field for ion energy analysis, JIP is the ion detector, IO is the central ion orbit of this ion optical system, and CC is the collision chamber and the ion injection hole. It has Si and an ion exit hole SO, and a collision gas such as Hθ is introduced.

The sample is ionized in the ion source S, the ions generated here are subjected to mass analysis in the magnetic field B, and ions with a specific mass determined by the ion accelerating voltage and the strength of the magnetic field B enter the collision chamber CG. The cleavage ions collide with neutral colliding gas molecules and are cleaved, and the cleavage ions enter the electric field E for energy analysis and undergo energy analysis.By changing the strength of the electric field and performing energy scanning, a spectrum of the cleavage ions is obtained. be able to.

The dimensions shown in the figure are based on the radius am of the central ion orbit in the magnetic field B. One of the features of the present invention is that the collision chamber CC has an electric field that increases significantly from the midpoint between the magnetic field B and the electric field E. In this example, the ion input end face of the magnetic field has a concave curvature within the central ion orbital plane, and its radius of curvature RMI is approximately 0.8 am.
In addition, the output end face of the magnetic field B is inclined with respect to the central ion orbit, and the angle ψ is about 7-0. Furthermore, the input end face and the output end face of the toroidal electric field have a life gorge as shown in the side view next to each of them. It has a concave curvature and its radius of curvature is r.

rl is approximately the radius of the central ion orbit of the electric field E, respectively.

The radius of curvature of the center line between the inner and outer electrodes in a cross section taken by a plane that includes the center of curvature of the central ion orbit of the toroidal electric field E and is perpendicular to the orbit plane is half the radius of curvature ae of the toroidal electric field.

When the ion optical system in this example is used simply as a double-focusing mass spectrometer, the image of the ion entrance slit S1 is formed on the ion exit slit S2, and there is little aberration at that time, especially on the central ion orbital plane. On the other hand, it has the characteristic that ions having a velocity component in the vertical direction can be well focused on the exit slit 82.

Effects The CA ion measuring device of the present invention uses a toroidal electric field as the electric field for energy analysis, and has the ability to focus even on ions having a velocity component perpendicular to the central ion orbital plane. Since it is placed close to the incident end face of the electric field for energy analysis, CA ions having a velocity component in a direction perpendicular to the central ion trajectory emitted from the collision chamber can efficiently enter the electric field for energy analysis. C
The detection sensitivity of A ions is improved.

[Brief explanation of the drawing]

The drawing is a plan view of an apparatus according to an embodiment of the present invention. XS...Ion source, B...Magnetic field for mass spectrometry, CC/
...Collision chamber, E...Toroidal electric field for energy analysis, MP...Ion detector. Agent Patent Attorney Kosuke

Claims (1)

[Claims] An ion source, a mass spectrometer that performs mass spectrometry on ions generated by the ion source, an electric field for ion energy analysis located behind the mass spectrometer on the ion trajectory, and an electric field for energy analysis between the mass spectrometer and the above mass spectrometer. and a collision chamber is installed on the ion orbit between the two, the electric field for energy analysis is a toroidal electric field, and the collision chamber is arranged close to the ion-containing end face of the electric field for energy analysis. Activation cleavage ion analyzer.