SU1340371A1 - Method of monitoring charged particles - Google Patents

Abstract

This invention relates to methods for detecting charged particles. The aim of the invention is to increase the recording accuracy by improving the temporal vacuum and the possibility of its adjustment. The goal is achieved by a certain notch mode, which causes only one particle to hit the recording detector for a short period of time. Such a rejection is carried out by the electric field of the deflecting system, to which a constant and pulsed voltage of a certain amplitude, duration and frequency is applied. The registration method can be applied in recording and monitoring devices where an increased temporal resolution is required. 2 Il. i (L 00 about with

Description

13A

The invention relates to an experimental method of nuclear physics and solid state physics.

The aim of the invention is to increase the recording accuracy by improving the temporal resolution and the possibility of its adjustment.

Fig. 1 shows a device for detecting charged particles; Fig. 2 illustrates the dependence of the total voltage on the detector on time.

The source of charged particles 1, focusing system 2 and deflecting system 3 of length 1 are sequentially installed on the same optical axis of the OO. At a distance L from the deflecting system 3 there is a recording detector 4 with a probe diaphragm 5 with a diameter Sg located in the focal plane of the system 2 Detector A is electrically connected to the input of the analyzing path 6. The dc voltage from sources 7 and 8, respectively, is supplied to the focusing and deflecting systems, and the pulse voltage from the generator at 9.

Possible bottom registration option. In the first case, the focusing system 2 from the constant voltage source 7 is supplied with the voltages necessary for focusing the particle beam along the axis 00 on the probe diaphragm 5. A constant voltage of 11 is applied to the deflecting system 3 from the voltage source 8 An electric field that deflects the particle beam to the distance S from the axis 00. At a constant voltage with a constant voltage, the rectangular-wave pulse voltage Uj is applied to the deflecting system 3,

. (U,

-Up) and c

pulse impulse 9. When a pulse arrives, DC voltage is compensated and particles will fall into the probe diaphragm 5 of detector 4. When these pulses last longer than the working time} of the recording-analyzing path, the impulses in the latter can only occur from particles detected by the detector during a single voltage pulse of duration, and, thus, the resolution time in this registration mode will be 2 and.

12

Consider the second registration registration, which allows to improve the temporal resolution, 15 in this mode a deflection voltage Uj is given to the deflecting system 3 by satisfying the lUpIt anti-opposite 1O1 sign relative to the constant voltage. With such a ratio of constant and pulsed voltages, only particles that fly through the deflecting system 3 can hit the detector, and the duration of the pulse front time at which the total voltage on system 3 changes sign (Fig. 2), t. e. when the scanning beam passes through the defining diaphragm 5. The resolution time ut in this case is determined by the relation

S, ut

 about

where Tf is the duration of the front of a rectangular pulse.

In this mode, both the period of the pulses and the duration of the pulses themselves must not be less than the working time of the recording and analyzing tract, in order to avoid overlapping from particles coming to the leading and falling edges of the pulse, it is reasonable to show that from the point of view of using technical capabilities pulse generator is a mode when the equality is equal to UK 2U.

The detector loading in both registration modes decreases by a factor of 1, where ut is the resolution time, s; - frequency of following rectangular voltage pulses, Hz.

A decrease in the detector load leads to an increase in the duration of its operation.

We show the example of the benefits. the proposed method in terms of time resolution. It is known that the resolution time in a known solution is 2 µs.

“At the same time, with the proposed method, for example, with the following parameters: UH 1.5 5 no; T 1 not; SP 0.03 m; 1 1 cm; L 20 cm; h - 0.3 cm, the resolving time for an electron with an energy of 6 I 5 keB will be: in the first mode, bt 5 is not; in the second mode / t 5 ps.

An electrostatic focusing system and a traveling type deflecting system can be used for implementation, with a wave resistance of 75 cm, a constant voltage source — standard le, such as BC-23, a square-wave generator with an output resistance of 75 Ohm, V In this case, the parameters of the elements indicated in FIG. 1 are as follows: R, - I MOhm, R, 75 cm, C, - -0.1 μF

The proposed method can be used to register electron beams, ions, and other charged particles. Such beams are widely used in electron microscopes, in electron-vacuum devices and in nuclear physics. the invention

The method of registering charged particles, in which the particles are focused and rejected by RO DRAGTs on charged particles by the electric field of the focusing and deflecting systems, in order to increase the recording accuracy by improving the time resolution and the possibility of its regulation, a constant and pulsed rectangular voltage is applied to the deflecting system, the values of which satisfy the ratios | and „| S UM, where Up is the constant value, and CC is the pulse of April, the constant and pulse voltages of the opposite sign, and the pulse following period Tg is chosen from the ratio Tg h C, where is the working time of the registrar tract.

Editor A.Ivanova

Compiled by V. Drygin

Tehred L. Serdyukova Proofreader I. Musk

Order 3389 Circulation 522 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

claims a method for detecting charged particles,> which focuses and rejects particles by exposing the charged particles to an electric field of a focusing and deflecting system, characterized in that, in order to increase the registration volume by improving the temporal resolution and its possibility regulation on the deflecting system and serves a constant voltage rectangular pulse whose values satisfy _(n and | ί | U _and (where U _n - value is constant, _and a and - the value of pulse second voltage, wherein the constant voltage and a pulse of opposite sign, the pulse repetition period T _c is selected from the relationship T _c b £, where c - working time enroll - analyzing tract. FIG. 1 134037 I