JPS60165034A - Split ion analyzing device by collision activation - Google Patents

Abstract

PURPOSE:To improve detection sensibility of CA ions by making it possible to regulate the position along the ion orbit surface while in the orthogonal direction to the ion orbit as well as the inclination around the axis vertical to the ion orbit surface in an analyzing device of a collision chamber by external operation. CONSTITUTION:A collision chamber CC is finely adjustable in the Y-direction orthogonal to the ion orbit inside the ion orbit surface while being minutely rotatable around the Z-axis vertical to the ion orbit surface. When only an incident hole Si is accorded with the center of an ion beam Ib by moving the collision chamber in the Y-direction, the ions being incident to the collision chamber are increased but the split ions in the same direction hit on the periphery of the outgoing hole So thus lowering the outgoing efficiency of ions. By adjusting the position of the collision chamber in the Y-direction together with adjusting the inclination around the Z-axis, the ion incident and outgoing efficiency can be hightened by almost 100%.

Description

[Detailed Description of the Invention] B. Industrial Application Field The present invention is directed to the so-called M-KES (Mass -analyzeaIon
Kinetic Energy Spectrum)
The present invention relates to a device for measuring.

When the parent ion is 2, the parent ion is cleaved into the ion and the neutral molecule N during flight. In other words, OK
”+No By investigating the state of such cleavage, useful information can be obtained for the structure of the ion and the qualitative determination of the compound.In the above-mentioned measurement, the primary ions generated by ionizing the sample are This method takes advantage of the natural cleavage caused by the internal energy that the primary ion possesses, but this method has been developed by colliding the primary ion with an appropriate gas molecule.
There is an analysis method in which the cleavage ion is measured by cleavage using n: CA). 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.

Let the mass of the ion (parent ion seen from the cleavage ion) that has just been emitted from the mass spectrometer be M, the velocity be V, the mass of the umbrella ion needle produced by the cleavage is ml, and the mass of the neutral molecule N is m2, the velocity of k and N produced by the cleavage is also ■, and the energy of each movement is -mlV2. Am2V2 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.

Conventional equipment for determining the position of CA ions as described above uses a dual-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. This device has a collision chamber in which a collision gas is introduced at an ion convergence point between a magnetic field and an electric field. This collision chamber is placed on the surface where a mass spectrum is formed by the mass spectrometer and needs to have the ability to select one spectral peak. 6 to 7 mm), and the ion exit hole is also a narrow slit in order to maintain the required pressure of the collision gas inside. For this reason, the ion exit hole in the collision chamber must be aligned accurately with the ion trajectory, but conventionally, the collision chamber installation depends on the precision of the structure, and the collision chamber is aligned with the designed ion trajectory. It was fixed so that the ion exit holes were aligned.

However, in the case of CA ion measurement, the mass spectrometer does not perform mass scanning and performs measurement by setting a single mass, so a slight error in the setting may cause the convergence point of ions of a predetermined mass to be at the ion entrance hole in the collision chamber. The line connecting the exit holes in the collision chamber was slightly tilted with respect to the ion trajectory, resulting in a low detection intensity of ions.

C. Purpose The present invention is intended to solve the above-mentioned problems of conventional devices for measuring CA ions.

2. Configuration The present invention provides a MIKES measuring device that enables positional adjustment along the ion trajectory plane and perpendicular direction to the ion trajectory and tilt adjustment around an axis perpendicular to the ion trajectory plane in the analysis device of the collision chamber by external operation. Figure 1 shows the entire apparatus of an embodiment of the present invention. S is an ion source, B is a magnetic field for mass spectrometry, CC is a collision chamber, E is an electric field for energy analysis, and MP is an ion source. is a secondary electron multiplier for ion detection. TO is the ion orbit, and the paper plane of the figure is the ion orbit plane. In the collision chamber CC, Sl is an ion entrance hole, So is an ion exit hole, and they are shaped like long slits in the direction perpendicular to the paper plane of the figure, that is, the ion orbital plane.
A collision gas such as the following is introduced. Ions of a specific mass that have passed through the magnetic field B converge on the ion entrance hole S1 of the collision chamber CG, enter the collision chamber, collide with the collision gas, become activated, and cause cleavage. The cleavage ions generated by the cleavage are emitted from the ion exit hole SO while maintaining the same velocity as the original ions, are energy analyzed by the electric field E for energy analysis, and detected by the ion detector MP. By performing an energy scan at , a spectrum of a single lateral ion produced by the cleavage of a parent ion of a specific mass can be obtained.

The collision chamber CC can be moved slightly in the Y direction perpendicular to the ion orbit within the plane of the drawing, that is, within the ion orbit plane, and can still be slightly rotated around two axes perpendicular to the ion orbit plane. P'l, P2
is a double knob located outside the vacuum chamber wall W of the analyzer.By turning PL, fine adjustment of the Y-direction position of the collision chamber CC is made, and by turning P2, 2＠ Adjust the tilt of the mawashi.

FIG. 2 shows details of the collision chamber position fine adjustment mechanism.

G is a cylindrical guide provided on the wall W of the vacuum chamber, through which the Y-direction adjustment rod Ri'' can airtightly slide in the Y direction and prevent rotation of the Y-axis rotary; the collision chamber CC is connected to this rod. It is held rotatably around the Z-axis by a bottle Zp at the tip of the rod, and is biased counterclockwise by a spring force.The portion of the Y-direction adjustment rod RY that protrudes leftward from the guide G. A knob PI is rotatably attached via a bearing b1.A screw T1 is formed on the inner surface of the knob PI and the outer surface of the guide G, and they engage with each other, so that when the knob PI is turned, Pl moves forward and backward in the Y direction, and the Y-direction adjustment rod moves in the Y direction to finely adjust the Y-direction position of the collision chamber CC.Furthermore, it passes through the Y-direction adjustment rod RY in the axial direction. A shaft rotation adjustment rod RZ is provided.Two rotation adjustment rods R
Z is airtightly slidable in the Y direction with respect to the Y-direction adjustment rod RY, and rotation of the Y-axis rotation is prevented.The right end of Z is in contact with the arm A protruding from the collision chamber CC. As the arm A moves forward and backward in the direction of the arrow, the collision chamber CC is rotated around two axes around the bin zp, and the inclination of the two axes 9 is adjusted. ” A knob P2 is rotatably attached to the left end of the Z-axis rotation adjustment rod RZ via a bearing b2, and a screw T2 is formed on the inner surface of the left end of the Y-direction adjustment rod RY and the outer surface of the handle of the knob P2.
are engaged with each other, and when knob P2 is turned, the same knob is connected to rod R.
Moves forward and backward in the Y direction with respect to M, and integrally moves the rod RZ in the Y direction.
As described above, the inclination of the two-axis rotation of the collision chamber CC is adjusted by moving forward and backward in the direction.

The connection between the collision chamber CC and the Y-direction adjustment rod RY is a bottle connection on the upper side, but they are connected by a leaf spring whose width is perpendicular to the plane of the drawing, and the collision chamber is adjusted by the deflection of this leaf spring. may be rotatable about two axes.

Figure 3 is a diagram explaining the present invention in detail, and figure a shows the case where the position of the collision chamber CC is not adjusted, and the relationship between the ion beam of the target mass and the collision chamber is generally As shown in this figure, many of the ions subjected to mass spectrometry cannot enter the collision chamber.

In this case, simply moving the collision chamber in the Y direction and aligning the entrance hole Si with the center of the ion beam will increase the number of ions entering the collision chamber, but the cleavage ions moving in the same direction will fall to the edge of the exit hole SO. , and the ion ejection efficiency is low.

FIG. 3 shows the case where position adjustment according to the present invention is performed,
Adjust the position of the collision chamber CC in the Y direction and also adjust the tilt of the two-axis rotation (1 is a book that uses an ion focusing electrode to efficiently guide ions emitted from the collision chamber to an electric field E for energy analysis, 2 is an extraction electrode that efficiently extracts ions from the collision chamber.

Effects According to the present invention, the detection sensitivity of cleavage ions can be greatly improved by optimally adjusting the position and inclination of the collision chamber, and the adjustment operation is easy because it can be adjusted from the outside at all times, and the adjustment operation is simple during device production and 2nd assembly. There is a margin for tolerance for errors, and manufacturing costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the entire apparatus according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view showing details of the collision chamber position adjustment mechanism of the same embodiment, and FIG. 3 is a detailed explanation of the present invention. This is a diagram. Engineering S...Ion source, B...Magnetic field for mass spectrometry, CC/
... Collision chamber, E... Electric field for energy analysis, MP...
・Ion detector, W... Vacuum chamber wall, Pl... Y direction adjustment knob, P2... Z axis rotation tilt adjustment knob,
RY...Y direction adjustment rod, RZ...2 @ rotating adjustment rod, TIJ T2...thread groove, bl, b2...bearing,
G...Cylindrical guide. Agent Patent Attorney Kosuke Agata

Claims (1)

[Claims] An ion source that ionizes a sample, a mass spectrometer that performs mass spectrometry on sample ions generated by the ion source, an ion energy analyzer that is placed behind the mass spectrometer on the ion trajectory, and the mass spectrometer. In an apparatus comprising a collision chamber placed on the ion trajectory and into which a collision gas is introduced between the ion trajectory and the energy analysis section, the collision chamber is located in the plane of the ion trajectory in a direction perpendicular to the same trajectory and in the same orbit. A fragmentation ion analyzer using collisional activation, characterized in that the tilt around the axis perpendicular to the surface can be adjusted from the outside.