JPS586945B2 - Ionography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ionography using a radiation-sensitive cell in which a gas that is ionized by radiation is sealed.

Conventional electron radiography involves forming an electrostatic latent image using the Carlson method (or a modified process thereof) using a photoconductive material that has slight sensitivity even in the X-ray region, such as a Se-deposited film.

(For example, U.S. Pat. No. 2,666,144, etc.) A method in which X-rays are converted into visible light using a fluorescent material or the like, and then an electrostatic latent image is formed by ordinary electrophotography.

(For example, U.S. Pat. No. 2,856,535, etc.) Furthermore, it is called ionography, and is a method in which a gas is ionized by X-rays, and this charge is deposited on an insulating plate to form an electrostatic latent image (for example, U.S. Pat. No. 2900515, German Publication No. 2258364, etc.) are known.

The present invention relates to this ionography.

Ionography was considered to utilize ionization of air by X-rays, as described in US Pat. There were drawbacks such as frictional electrification and the appearance of discharge patterns.

Furthermore, as in German Publication No. 2258364, improvements such as using xenon gas as the ionized gas were made to increase the X-ray sensitivity.

However, since the gas directly contacts the insulating film, the gas leaks every time the insulating film is removed, and the gas must be replenished.

Furthermore, when gas is used at high pressure, a complicated device is required to prevent gas leakage.

Furthermore, the use of more expensive gases would lead to increased copying costs, and of course toxic gases could not be used.

The present invention solves the above-mentioned drawbacks and provides an ionography system characterized by completely sealing the gas inside the container.

Furthermore, the present invention provides ionography using a gas-sealed radiation-sensitive cell that does not require gas replenishment and can be used semi-permanently with both expensive and toxic gases.

Furthermore, the present invention provides a method for obtaining a video signal using the radiation-sensitive cell.

That is, the present invention ionizes the gas by irradiating a radiation-sensitive cell, which is a sealed cell with a conductor on one surface and a plurality of needle ends on the opposite surface, in which a gas is sealed. , an ionography system characterized by forming an electrostatic latent image on an insulator placed near the end of a needle.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an example for explaining the operation of the present invention.

The closed container 1 may be made of a single material, or the front surface (radiation east side), side surface, and back surface may be made of different materials.

In the former case, it is necessary that the material has good transparency to radiation 5 and is made of an insulating material, and in the latter case, the front surface must have good transparency to radiation, such as beryllium, and the back surface must be made of an insulating material. It is necessary.

If the front surface is an insulating material, the inner wall is coated with an electrode 2 that is transparent to radiation.

For example, an aluminum, vapor deposited film, or carbon film with a thickness of about 500 Å is used for this.

A large number of needle ends 4 are stamped on the back surface.

Both ends of the needle protrude from the inner surface of the back surface and the outer surface of the back surface, respectively.

The ends of the needles may be arranged in squares in a matrix or in long thin slits.
It is preferable that they are arranged at intervals of m.

Further, it is desirable that the diameter of the needle end is several tens of percent or less of the interval.

Gas 3 is sealed inside the container.

This gas is preferably one that is easily ionized by the radiation used.

When enclosing gas, it is necessary to avoid mixing of powder mist into the gas, and of course, the inner wall of the container must be sufficiently cleaned.

Radiation flux that contains information about the object (corresponding to the transmitted density of the object 6, such as X-ray rays used for human body observation, or radiation flux that corresponds to the transmitted density of the object 6, such as X-ray rays used for human body observation, or X-rays and γ-rays used in crystal analysis, etc.) It may be something like a pattern.

) ionizes the gas in the container.

The ionized gas is attracted to the electric field, and depending on the charge, it becomes a cathode or a cathode, respectively.
Move to the anode.

In the case of FIG. 1, the charge discharges through the needle end with the cathode 7, creating an electrostatic latent image on the insulating material 8.

This is developed and fixed by a known developing means.

1 may be applied to the front electrode 2, or in some cases, the front electrode may be grounded and a voltage may be applied to the substrate electrode.

The power supply voltage E is set to a voltage that does not cause gas spark discharge.

It is desirable to set the power supply voltage so as to correspond to corona discharge occurring in the immediate vicinity of the needle end, or just before it occurs.

The distance between the outside of the needle end and the surface of the insulating material is usually set to 50 μm or less.

When electrostatic recording paper is used as the insulating material, appropriate spacing can be maintained due to the unevenness of the surface of the recording paper.

When the surface of the insulating material is smooth, such as a Mylar film, discharge can be efficiently generated between the needle end 4 and the electrode 7 by using a container and a backing material as shown in FIG. 2, for example.

Such a structure is achieved, for example, by shortening the needle end by means of chemical etching, reverse sputtering, or the like.

Similarly, as shown in Figure 2, the inner end of the needle is made into a point, and the electric field in the vicinity is increased to stabilize the ionization of the gas.
Furthermore, the efficiency of ionization multiplication can be increased.

The needle tip may be made of a single material, such as tungsten, but if the radiation is It is made by coating 9 with a thick external photoelectric effect,
Ionization of the gas by emitted electrons may also be used.

Of course, the photoemissive material 9 can be coated not only on the needle ends, but also on the inside of the back of the container, but must not reduce the insulation between the needle ends.

Furthermore, it goes without saying that in FIG. 1, a thermoplastic film or the like may be used as the insulating material, and means such as recording an electrostatic latent image as irregularities on the material may also be used.

Furthermore, for example, when the radiation flux 5 is not a parallel flux as shown in FIG. 4, it is also effective to make the closed container 1 arc-shaped to prevent deterioration of resolution.

Similarly, as described above, the needle ends may be arranged in a matrix or in elongated slits, but in this case, a latent image can be created by scanning the cell.

FIG. 5 shows the case where the above-described cell is used in an X-ray vidicon.

An electron beam 10 emitted from an electron gun 12 through an anode 13 scans over the needle end 4, and a current flowing in accordance with the X-ray intensity is obtained as a video output 11 through the capacitor.

The video output is obtained by a conventional video amplifier and processed as a time series signal.

As is clear from the above description, the present invention has the following advantages: 1) Since the gas ionized by radiation is sealed in the cell, once it is sealed, it can be used semi-permanently.

Therefore, expensive gases can be used, and even toxic gases can be used.

2) Furthermore, since the insulating film is not inserted into or taken out of the gas as in German Published Publication No. 2258364, no powder mist is mixed into the gas.

This eliminates the occurrence of discharge patterns caused by dust and the like.

3) Current multiplication effect due to corona discharge can be used by the electric field near the needle end.

This method operates more stably than a method that sets the applied voltage at the critical point of spark discharge.

4) Increased voltage near the needle tip increases the efficiency of the external photoelectric effect of the needle tip material (or coated material).

5) It becomes possible to apply the principles of ionography to photography tubes.

It has the following characteristics.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an aspect of the radiation-sensitive cell of the present invention and ionography using the same. FIGS. 2 and 3 are explanatory diagrams showing modified examples of the radiation-sensitive cell. FIG. 4 is an explanatory diagram showing a modification of the radiation-sensitive cell and ionography of the present invention. FIG. 5 is an explanatory diagram showing a method of obtaining a video signal according to the present invention and an embodiment of a photographing tube used therein. 1... Airtight container, 2... Front electrode, 3
...Gas, 4...Needle end, 5...
・X-ray, 7...Substrate electrode, 8...Insulator, 9...Photoelectric emission material, 10...Electron beam, 11... ...Video output, 12...
...electron gun, 13...anode.

Claims (1)

[Claims] 1 A gas is sealed in a sealed cell that has a conductor on one side and a number of needle ends on the opposite side, and the cell is irradiated with radiation to ionize the gas, and the needle end side Ionography is characterized by forming an electrostatic latent image on an insulator placed nearby.