SU813535A1 - Time analizing device - Google Patents

Description

(54) TIME ANALYZING DEVICE

one

The invention relates to electronic engineering, in particular, to devices containing electronic-optical converters (EOC) for analyzing fast processes in a time-lapse or photo-chronographic registration mode.

The time is known for an analyzing device containing an electron-optical converter designed to study and analyze ultrafast processes I.

The disadvantage of this device is the relatively low temporal resolution, which prevents its use for recording processes in the picosecond range.

It is also known an analyzing device comprising an electron-optical image converter, comprising a photocathode, an accelerating and focusing electrodes, an anode diaphragm, an electronic shutter, a deflecting system, and a luminescent screen 2.

The disadvantage of this time analyzing device is also relatively low temporal resolution.

The purpose of the invention is to increase the temporal resolution.

This goal is achieved by the fact that the deflection system is made in the form of a broadband symmetric path with distributed parameters, formed by two two-wire lines with the same characteristic impedance, and the outer conductors of the lines are connected and constitute the vacuum-tight shell of the deflecting system to the input connectors of the lines connected to the generator of symmetric sweep pulses, and to the output connectors - coaxial matching paths with a terminal load equal to the characteristic impedance of two-way single lines and of such length that the double propagation time of the signal from the deflecting system to the terminal load exceeds the maximum sweep pulse duration, and an electron trap is installed between the deflecting system and the luminescent screen, made in the form of a truncated cone with a smaller base facing the side deflecting system converter. In addition, the EOP electronic shutter is made in the form of two pairs of deflecting plates, between which a gate diagram is installed, with

each of the deflecting plates of the electronic gate has two leads for connecting these plates with one lead to the gate pulse generator, and to the high-frequency matching path with a terminal load equal to the wave resistance of the path and such a length that twice the signal propagation time from the plates to the terminal load exceeds the shutter pulse duration.

The drawing shows the time analyzing device.

The device contains a photocathode 1, an accelerating electrode 2 with a fine-grained mesh, a focusing electrode 3, an anode diaphragm 4, an electronic shutter, made in the form of two pairs of deflecting plates 5 and 6, between which the shutter aperture 7 is installed, deflecting system 8 in the form of two two-wire lines 9, the outer conductors of which are connected and form a vacuum-tight sheath 10, an electronic trap 11, a luminescent screen 12, a fiber-optic disk 13 for contact photographing an image from a luminescent crane.

Two-wire lines 9 of the system of deviation are connected; s to the generator 14 and sweep pulses on one side and to the matching paths 15 with termination 16 - on the other. The deflecting plates 5 and 6 of the electronic shutter are connected to the generator 17 of the gate pulses on one side and to the high-frequency matching path 18 with termination load 19 on the other.

- Time analyzing device operates as follows.

The radiation incident on the photocathode 1 causes the emission of photoelectrons, which, under the action of an electric field formed between the photocathode 1 and the accelerating electrode 2, are accelerated and focused on the screen 12 using an electron lens formed by the accelerating electrode 2, the focusing electrode 3 and the anode diaphragm 4. The image from screen 12 is transferred to the outer (and relative to the image intensifier) surface of the fiber optic disc 13, where it can be fixed to a film or some photoelectronic detector. In the absence of a signal on the photocathode 1 from the process being investigated, the EOC is closed by supplying an electronic gate with locking voltage to the plates 5 and 6 (EjAn Unlocking the image is performed by applying to the plates 5 and 6 of the electronic gate an unlocking voltage pulse from the gate pulse generator 17, as a result which causes the photoelectron beam to move relative to the slit of the shutter diaphragm 7. The image on screen 12 appears at the moment the electron beam enters the slit of the shutter diaphragm 7. The voltage pulse from the generator 17 the gate pulses, the plates 5 and 6 of the electronic gate pass further through the high-frequency matching path 18 to the terminal load 19. The reflected voltage pulse signal arising from the load 19 (due to non-ideal matching in the wide frequency range) passes through the high-frequency matching path 18 to the plates 5 and 6, through the time of double passage of a voltage wave along a path. With an electrical length of path 18, corresponding to a double signal propagation time, which is longer than the maximum time Pulse gate voltage, the reflected signal comes to the plates 5 and 6 after the locking in the image intensifier and the image does not cause image distortions, resulting in the loss of boiling temporal resolutions Display resolution image intensifier.

The image is scanned across the screen 12 by broadband lines 9 systems. We are 8 deviations when applying to them.

voltage pulses from the generator 14 sweep pulses. At this m., The speed of scanning the image across the screen can be equal to several speeds of light, which is necessary for reliable recording.

5 images with a picosecond and subpicosecond time resolution. After passing the wideband bi-wiring lines 9 of the deflection system, the sweep pulses pass through the matching paths 15 with a terminating load 16. The reflected sweep pulse signal appearing on the terminating load 16, due to mismatch in matching the line in the wide frequency range, passes through the matching path 15 and after equal to the doubled range of the signal through it, goes to the two-wire lines 9 of the deflection system, where the reflected pulse causes an abrupt change in the scanning speed. If the electrical length of the matching paths 15 is such that the corresponding mileage of the signal on it from the deviation system to the load and back is longer than the maximal pulse duration of the sweep, then the reflected signal comes to the deviation system after the end of the scan image on the screen and does not worsen the time resolution EOP.

After the passage of the deflecting system 8, the electron beams deflected by an angle larger than necessary to rotate the image in all the working fields of the luminescent screen 12 go beyond the conical part of the electron trap II, which is under the potential of the vacuum-tight deflector shell 10 system 8. As a result, the device does not reduce the image contrast on the luminescent screen under the action of electrons, elastically reflected from the side walls of the vacuum cylinder, also leading to a decrease and recording processes with picosecond and subpicosecond temporal resolution.

Conducted tests of prototypes showed the possibility of their effective application in photochronographic systems for recording fast processes with picosecond time resolution.

Claims (2)

1. A time analyzing device including an electron-optical image converter containing a photocathode, an accelerating and focusing electrodes, an anode diaphragm, an electronic shutter, a deflecting system, and a fluorescent screen, characterized in that, in order to increase the temporal resolution, the deflection system made in the form of a broadband symmetric path with distributed parameters, formed by two two-wire lines with the same characteristic impedance, and the outer conductors of the lines are connected are a vacuum-tight shell of the deflecting system, a symmetric sweep pulse generator is connected to the input line connectors, and coaxial matching paths with a termination load equal to the wave resistance of the two-wire lines and such a length that the double signal propagation time through them from the deviation system to a terminal load exceeds the maximum duration of a sweep pulse, and an electronic circuit is installed between the deflecting system and the luminescent screen the trap is made in the form of a truncated cone with a smaller base facing the deflecting system of the converter. 2. A device according to claim 1, characterized in that the electronic shutter tube is made in the form of two pairs of deflecting plates, between which a shutter diaphragm is installed, each of the deflecting plates of the electronic shutter having two leads for connecting these plates with one 5 to a gate pulse generator, and another to a high-frequency matching path with a termination load equal to the wave impedance of the path and of such a length that the doubled propagation time of the signal from the plates to the termination load exceeds the duration of the gate pulses. Sources of information taken into account in the examination 1.Butelov M.M. Electron-optical converters for studying ultrafast processes. “Advances in scientific photography, 1959, No. 6, p. 76. 2. Korobkin V. V. et al. Electron-optical equipment of the LPI of the USSR. Instruments of experimental physics. Scientific 0 works VNIIOFI. Ser. V. 1972, no. 1, s. 166-173 (prototype).