JPH0321003Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charged particle detector that can accurately detect charged particles with a simple configuration.

[Prior art]

FIG. 2 shows a conventional Faraday cup-type charged particle detector, in which 1 is a conductive container having a charged particle entrance 2, and 3 is a conductive container that detects charged particles B entering the container 1. This is an aperture plate that limits the ground potential. The charged particles restricted by the aperture plate 3 enter the container 1 through the entrance port 2, flow into the conductive container 1, and are detected. The detection signal is amplified by an amplifier 4 connected to the container 1, and supplied to a recorder or display device (not shown) to measure the beam current value of the charged particles.
By the way, when charged particles enter the lower part of the container, secondary electrons are generated from the incident part, but if these secondary electrons escape to the outside of the container 1, it is difficult to accurately measure the beam current value. become unable to do so.
Usually, as a countermeasure against this, an electrode 6 to which a negative voltage is applied from a power source 5 is placed on the top of the container 1.
The structure is such that secondary electrons escaping to the outside of the container 1 are returned to the inside of the container 1. However, such a configuration requires a power source 5 and an electrode 6, making the entire detector expensive.

〔the purpose〕

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a charged particle detector that can accurately detect charged particles with a simple configuration.

〔composition〕

A charged particle detector based on the present invention includes a conductive container having a charged particle entrance, and measures the current value of charged particles flowing into the container through the entrance. It is characterized by an insulator placed inside the container near the entrance of the container.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, the same components as those in FIG. 2 are given the same numbers, and detailed explanation thereof will be omitted. The embodiment shown in FIG. 1 differs from the configuration shown in FIG. 2 in that the power source 5 and electrode 6 shown in FIG. This is the point where a sheet-like insulator 7 is pasted on. In such a configuration, in the initial state when charged particles are detected, a portion of the secondary electrons generated due to the incidence of charged particles B into the container 1 escapes to the outside of the container through the entrance port 2; A part of the secondary electrons adheres to the surface of the insulator 7 and charges the insulator in a relatively short period of time. As a result, the surface of the insulator is maintained at a negative voltage, and the secondary electrons generated thereafter are prevented from proceeding to the outside of the container by the charged insulator.

In this embodiment, the sheet-like insulator 7 is attached to the inner wall of the container 1, but the insulator is not limited to a sheet-like shape, but may be a plate-like material. Further, the insulator may be placed near the entrance and does not necessarily need to be placed in close contact with the container.

〔effect〕

As described in detail above, in the present invention, charged particles can be accurately detected using a simple configuration in which an insulator is placed inside a conductive container without providing a power source or electrodes.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows a conventional Faraday cup type charged particle detector. 1... Conductive container, 2... Charged particle entrance port, 4
...Amplifier, 7...Insulator.

Claims (1)

[Scope of utility model registration request] In a charged particle detector that is equipped with a conductive container having a charged particle entrance and measures the current value of charged particles flowing into the container through the entrance, an insulator is installed inside the container near the entrance of the container. A charged particle detector characterized by the placement of a body.