JPH04101399U - Slit for beam trajectory monitoring in ion beam analyzer - Google Patents

Abstract

(57) [Summary] [Purpose] In an ion beam analyzer that distributes the ion beam from the analyzer to multiple beam lines,
A pair of slits placed in the beam line monitor the deviation of the ion beam trajectory in two dimensions. [Configuration] A pair of slits on the left and right (1), each with a central slit (2), and upper and lower slits on both sides (3),
(4) In addition to dividing these slits into
(5), the current value flowing through each slit is measured independently, and the deviation of the beam trajectory in the horizontal direction is determined from the difference in the current value between the left and right slits (1).
(3), (4) and the current value of the central slit (2) to monitor the deviation of the beam trajectory in the vertical direction. [Effect] The deviation of the ion beam trajectory can be confirmed two-dimensionally, and the beam trajectory can be adjusted and confirmed efficiently.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a slit for beam trajectory monitoring in an ion beam analyzer. In detail, the ion beam from the accelerator is distributed to multiple beam lines for use. In the ion beam analyzer, the deviation of the ion beam trajectory of each beam line This invention relates to a beam trajectory monitoring slit that can monitor the beam trajectory in two dimensions.

0002

[Conventional technology]

In an ion beam analyzer that uses a large electrostatic accelerator, as shown in Figure 3, a high-energy ion beam emitted from an accelerator a is normally sorted by ion type and energy by an ion deflection electromagnet b. , a configuration in which ion beams with different characteristics are distributed to a plurality of beam lines c ₁ , c ₂ , c ₃ formed in a vacuum path, guided to vacuum sample chambers d ₁ , d ₂ , d ₃ and used for various analyses. is taken. In addition, in these ion beam analyzers, each time the ion type or energy of the ion beam is changed, the beam trajectory must be adjusted to ensure that the ion beam cannot correctly hit the sample in the vacuum sample chamber. Slits _{e 1} , e ₂ , e ₃ for beam trajectory monitoring are installed on the entrance sides of ₁ , c ₂ , and c ₃ .

0003 Typical examples of conventional slit configurations installed in these ion beam analyzers is shown in [Figure 4]. In addition, (a) of [Figure 4] is a cross-sectional view, and (b) is a cross-sectional view of (a). It is an AA sectional view of. In this example, inside the vacuum duct (43) forming the beam line. A pair of parallel slits (41) facing each other in the horizontal direction are connected to the insulating flange (42). is isolated from the vacuum duct (43), while connected to an external ammeter (44). Ru. Under this configuration, the ion beam B shown by the dashed line hits the pair of slits (41). Then, a current flows that is proportional to the area of contact. Therefore, the pair of slits (41) The current flowing through each is detected by an ammeter (44), and from the difference in current value, the ion beam The horizontal trajectory deviation of B can be monitored.

0004

[Problem that the idea aims to solve]

Conventionally, in order to change the type of analysis, the ion beam was distributed to other beam lines. When using the While adjusting the horizontal deviation of the ion beam trajectory, this In this case, the deviation of the beam trajectory in the vertical direction cannot be monitored at all, and the ion I couldn't tell if the beam was shifting upward or downward.

[0005] Therefore, vertical adjustment is necessary to adjust the current value flowing through the sample in the vacuum sample chamber and the Check the current value detected by the Faraday cup placed just before the sample, or perform a vacuum test. This method relies on visual confirmation of the beam irradiation position through a quartz window installed in the sample chamber. , By checking with these and monitoring results with paired slits, horizontal → vertical → I set the optimal beam trajectory while repeating horizontal and horizontal adjustments. For this reason However, much of the process depended on the skill and experience of the operator, which was time-consuming and labor-intensive.

[0006] On the other hand, by adding a pair of slits facing each other perpendicularly to the beam line, The above problem can be solved, but in this case, a pair of slits on the same beam line This increases equipment cost and requires initial slit adjustment. Furthermore, the beam line formed in the vacuum path is subject to an increase in outgas. This is undesirable because it tends to have adverse effects such as a decrease in conductance and conductance.

[0007] The purpose of this invention is to divide the conventional pair of slits facing each other in the horizontal direction. A simple method that has less negative impact on the beamline is to make it electrically independent. By simply making improvements, it is possible to monitor two-dimensional beam trajectories both vertically and horizontally. The goal is to improve the efficiency of ion beam trajectory adjustment and confirmation operations.

[0008]

[Means to solve the problem]

The present invention has the following configuration to achieve the above object. In other words, the main idea The slit for beam trajectory monitoring in the proposed ion beam analyzer is An ion system that distributes the ion beam emitted from the device to multiple beam lines. It is located within each beamline of the beam analyzer and is used to control the reference beam trajectory within the beamline. The current of the ion beam colliding at a pair of slits that are axially symmetrical and opposite each other. An ion beam that detects the current value and detects the deviation of the ion beam's trajectory from the current value. In the beam trajectory monitoring slit in the analyzer, each pair of slits If this is divided into three parts, a central slit and end slits on both sides, Both are characterized in that each of these slits is electrically independent.

[0009]

[Effect]

In the present invention, a pair of slits are arranged axially symmetrically across the reference beam trajectory. Each is divided into three parts: a central slit and end slits on both sides. At the same time, each slit is electrically independent, so each slit is The current value flowing through each is taken out independently, and the ion It is possible to simultaneously detect deviations in the beam's trajectory both vertically and horizontally. In other words, from the difference in current value between a pair of slits facing each other across the reference beam trajectory, , can detect the deviation of the beam trajectory in the opposing direction, and can detect the center part divided into three parts and the edges on both sides. From the difference in current value between the two slits, the beam in the direction perpendicular to the opposing direction of the pair of slits is determined. It is possible to detect deviations in the program trajectory.

0010

【Example】

An embodiment of the present invention will be described below with reference to FIG. 1. [Figure 1] shows the structure of this invention. FIG. 2 is a cross-sectional view of the beam trajectory monitoring slit of the embodiment, and (a) is a cross-sectional view. , (b) is a longitudinal sectional view.

[0011] In [Figure 1], (1) is a slit, and this slit (1) has an outer shape. is in the form of a plate, and inside the vacuum duct D that forms the beam line, is shown by the dashed line in the figure. The left and right beams are placed opposite each other with their side edges parallel to each other, with the reference beam trajectory B axially symmetrically sandwiched between them. It is arranged in such a way that

0012 In addition, this slit (1) is attached to the central slit (2) and both above and below it. upper and lower slits (3), (4), central slit (2) and upper and lower slits (3), (4) and an insulating plate (5) interposed between them to insulate and connect them. has been done. That is, in the vertical direction perpendicular to the reference beam trajectory B, the electrical It is divided into three independent components. The vertical width of the central slit (2) is the width of the beam guided to the beam line. The width is set to be approximately the same size or smaller than the on-beam beam diameter.

[0013] The pair of slits (1) on the left and right are connected to the vacuum duct D via the support rods (6), respectively. On the other hand, the support rod (6) is insulated from the vacuum duct D by the insulating flange (7). ing. In addition, a pair of slits (1), each central slit (2), and upper and lower The slits (3) and (4) are individually connected to each of the six ammeters (8) placed outside. It is said that the current value flowing through each can be measured independently.

[0014] In the beam trajectory monitoring slit of this embodiment having the above configuration, the beam The trajectory of the ion beam guided to the beam line is monitored as follows.

[0015] When the beam diameter of the ion beam is approximately the same as the width of the central slit (2); The ion beam is on the reference beam trajectory B and passes through the center of the pair of slits (1). When this happens, the current values flowing through the left and right central slits (2) are equal. Now, when the trajectory of the ion beam shifts upward, a current flows through the upper slit (3). When it shifts downward again, current flows through the lower slit (4), and the central slit The current value of (2) decreases. In this state, the trajectory of the ion beam also changes horizontally. If misaligned, the upper slit (3) or lower slit (4) and center slit (2) A difference occurs between the current values on the left and right sides. Therefore, a pair of slits (1) inside each From the current values of the central slit (2) and upper and lower slits (3) and (4), the beam beam Simultaneously monitor the trajectory of the ion beam guided in the horizontal and vertical directions. be able to.

[0016] When the beam diameter of the ion beam is larger than the width of the central slit (2); When the ion beam is passing on the reference beam trajectory B, the center of the left and right The current value flowing through the slit (2) is the same, and the current value flowing through the upper slit (3) and the lower slit (4) and the current value are also equal. And now, when the trajectory of the ion beam shifts upward, The current value increases in the upper slit (3), and the current value decreases in the lower slit (4). Ma On the other hand, when it shifts upward, the current decreases in the upper slit (3), and the current in the lower slit (4) decreases. The current value increases. Furthermore, if the trajectory of the ion beam shifts in the horizontal direction, the upward and downward There is a difference in the current values on the left and right sides of the central slits (3), (4) and the central slit (2). Therefore, the trajectory of the ion beam can be monitored in the same way as in the above case.

[0017] In this way, the trajectory of the ion beam can be monitored simultaneously in the horizontal and vertical directions. In the beam trajectory monitoring slit of this embodiment, the beam from the reference beam trajectory B is Since the deviation of the trajectory can be confirmed two-dimensionally, the adjustment operation becomes much easier.

[0018] In addition, in this example, the pair of slits (1) each center slit (2) and Connect the upper and lower slits (3) and (4) to each of the six ammeters (8) individually, Each current value was measured independently, for example, as shown in the schematic diagram. As shown in Figure 2, connect the left and right center slits (2) to individual ammeters (8). At the same time, connect the left and right upper slits (3) to one ammeter (9), and Even if the measurement system is one in which the slit (4) is connected to another ammeter (10), this example It can have similar functionality. In addition, in this example, the pair of slits were made to face each other in the horizontal direction, but the present invention are not limited to this, for example, the same effect can be achieved even if these are vertically opposed. The effect of this can be obtained. Also, we will discuss how to insulate each slit to make it electrically independent. However, it goes without saying that the invention is not limited to this embodiment.

[0019]

[Effect of the idea]

As described above, according to the present invention, each pair of slits facing each other is divided into 3 minutes. This creates a negative impact on the beam line formed in the vacuum path. Two-dimensionally monitors ion beam trajectory deviation with a simple configuration that does not affect The trajectory can be easily adjusted and confirmed with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a beam trajectory monitoring slit according to an embodiment of the present invention, in which (a) is a cross-sectional view, and (b) is a cross-sectional view taken along line A-A in (a).

FIG. 2 is a schematic diagram illustrating another embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram of an ion beam analyzer.

FIG. 4 is a cross-sectional view of a conventional beam trajectory monitoring slit, in which (a) is a cross-sectional view, and (b) is a cross-sectional view taken along line A-A in (a).

[Explanation of symbols]

(1) --Slit (2) --Central slit (3) --Top slit (4) --Bottom slit (6) --Support rod (7) --Insulating flange (8) --Ammeter D --Vacuum duct B--Reference beam trajectory

Claims (1)

[Scope of utility model registration request] [Claim 1] Disposed within each beam line of an ion beam analyzer that distributes the ion beam emitted from the accelerator to a plurality of beam lines, and facing each other axially symmetrically with respect to the reference beam trajectory within the beam line. In the slit for beam trajectory monitoring in an ion beam analyzer, which detects the current value of the colliding ion beam with a pair of slits and detects the deviation of the trajectory of the ion beam from the current value, each pair of slits is A slit for beam trajectory monitoring in an ion beam analyzer, characterized in that the slit is divided into three parts: a slit and end slits provided on both sides of the slit, and each slit is electrically independent.