RU215606U1 - Galvanic Pulsed X-Ray Sensor - Google Patents

Abstract

The utility model relates to the field of nuclear physics and can be used to detect ionizing radiation, for example, to detect powerful X-ray fluxes in experimental studies.

In a galvanic sensor of pulsed X-ray radiation, containing a dielectric plate, on both sides of which electrical contacts are made, the first contact along the radiation path is made in the form of an annular gold coating 1–5 μm thick, the surface of the dielectric plate facing the annular coating has a roughness R _z ≤1 nm, the second contact on the opposite side of the plate is made in the form of a continuous gold coating with a thickness of 1-5 μm. The dielectric plate can be made of quartz or sapphire, its thickness is 200-300 microns. The outer diameter of the annular coating can be D=18-19 mm, and the inner diameter d=14-15 mm. 2 w.p. f-ly, 5 ill.

Description

The utility model relates to the field of nuclear physics and can be used to detect ionizing radiation, for example, to detect powerful X-ray fluxes in experimental studies. Many different methods for measuring radiation parameters have been proposed and used [1], in most cases based on the effect of ionization of atoms under the action of radiation. Research in the field of inertial thermonuclear fusion has set new diagnostic tasks [2], in particular, the development of a method for detecting plasma electromagnetic radiation that meets the following basic requirements:

1) the operating range of measurements should be in the region of quantum energies (25-10000) eV;

2) the resolution in time must be in the range of units of ns;

3) the linear area of sensitivity of the sensor should be above the power level of the radiation flux I~1 MW/cm ² .

Usually, to register the intensity of pulsed X-ray radiation, solid-state semiconductor detectors are used, the sensitivity of which is determined by the energy consumption ΔE required to form a pair of charge carriers. Silicon-based detectors require ΔE~3 eV, diamond-based detectors require ΔE~13 eV. The analysis shows that in research on inertial thermonuclear fusion, in order to detect radiation in the operating sensitivity range, it is necessary to remove the detector (even a diamond one) in vacuum at a distance of several tens of meters from the radiation source, which is quite expensive and not always feasible in real conditions. The use of filters that attenuate the intensity of the incident radiation simultaneously distorts its spectral composition, which makes it impossible to identify the processes occurring in a thermonuclear target.

In addition to these, inertial thermonuclear fusion facilities for routine measurements of powerful X-ray fluxes use secondary emission detectors, the sensitivity of which is varied by changing the cathode material [3]. These secondary emission detectors (SRD) can be considered as analogues of the present invention. However, the use of X-ray WFDs, as well as semiconductor ones, due to the high response to ionizing radiation, can only be used with the use of various attenuating filters. The implementation of this diagnostic technique requires vacuum conditions, the presence of a high-voltage source in the measuring circuit, and taking into account the dependence of the emission response on the energy of the measured radiation quanta and the state of the emitting surface, which is rather quickly modified at a high power of the measured radiation fluxes.

Closest to the claimed technical solution (prototype) is a method for reliable measurements of high radiation intensities I~(10 ⁵ ÷10 ⁷ ) W/cm ² while simplifying the measurement scheme and reducing its cost, presented in the patent [4]. To achieve the specified technical result in a known method for registering pulsed ionizing radiation, in which, in the process of measuring an electrical signal that occurs under the action of radiation in a solid radiation-sensitive element with a relatively high energy of formation of free charge carriers ΔE, for example, KU1 glass (ΔE~150 eV ), which is made in the form of a dielectric plate with the first and second metal contacts, the contacts are applied on two opposite planes of the plate, having an area, and the thickness of the first contact makes it transparent to ionizing radiation, the detector based on the said radiation-sensitive element is installed in the path of the registered ionizing radiation in such a way that the side of the plate with the first contact is oriented towards the ionizing radiation.

The disadvantages of the prototype of the invention [4] include a significant rise time of the front signal (40 ns) as a characteristic of its performance on the impact of pulsed x-rays; as well as a strongly delayed response to the action of pulsed X-ray radiation.

The technical problem, which is solved by the proposed design of the active element of the galvanic sensor of pulsed X-ray radiation, is to increase the values of its speed when detecting ionizing radiation according to the method [4].

EFFECT: ensuring the manufacture of an efficient and sensitive active element of a galvanic sensor of pulsed X-ray radiation with a power density of up to 2 MW/cm ² .

The stated technical problem and the result are achieved as a result of the fact that in a galvanic sensor of pulsed X-ray radiation, containing a dielectric plate, on both sides of which electrical contacts are made, the first contact along the radiation path is made in the form of an annular coating of gold 1-5 μm thick, the surface of the dielectric plate facing the annular coating has a roughness R _z ≤1 nm, the second contact on the opposite side of the plate is made in the form of a continuous coating of gold with a thickness of 1-5 microns. The dielectric plate can be made of quartz or sapphire, its thickness is 200-300 microns. The outer diameter of the annular coating can be D=18-19 mm, and the inner diameter d=14-15 mm.

The essence of the utility model is illustrated in the presented figures.

Fig. 1 - front view of the sensor.

Fig. 2 - section of the sensor along A-A.

Fig. 3 is a diagram of a device for detecting pulsed x-ray radiation based on the proposed galvanic sensor.

FIG. 4. Comparison of signals from various detectors of pulsed X-ray radiation with a pulse power density of ~2 MW cm ^-2 .

Fig. 5 - AFM images of the front (working) surfaces of plates of single-crystal sapphire in areas of 1x1 μm ² after chemical-mechanical polishing to R _z ≈0.1 nm (a) and after mechanical polishing to R _z ≈1.2 nm (b); radiation detector signals (X-ray pulse power density ~2 MW cm ^-2 on the basis of the indicated plates of single-crystal sapphire after chemical-mechanical polishing (c) and after mechanical polishing (d).

The proposed sensor 1 contains a dielectric plate 2 with working surfaces 3 and 4. An annular gold coating 5 1-5 µm thick is applied to surface 3, and a solid gold coating 1-5 µm thick is applied to surface 4. The roughness of the surface 3 facing the X-ray radiation is R _z ≤1 nm.

The sensor is used in a device for recording pulsed ionizing radiation (Fig. 3), containing a load resistance 7 and recording equipment 8,. like an oscilloscope.

The sensor is used as follows. The first contact, located on the side of the plate oriented towards the ionizing radiation, is grounded, and the negative voltage response that occurs on the opposite side of the plate is transmitted via a coaxial cable to the recording equipment, such as an oscilloscope. One end of the central conductor of the coaxial cable is connected to the second contact of the sensing element and the first output of the load resistance, the second end of the central conductor of the coaxial cable is connected to the recording equipment, and the braid of the coaxial cable and the second output of the load resistance are grounded.

EXAMPLE #1

The source of pulsed X-ray radiation (total peak power up to ¹⁰¹³ W) was the plasma of a megaampere Z-pinch, which was realized on a specialized thermonuclear facility Angara-5-1 [5]. The pulse power density on the sensors in all cases was ~2 MW cm ^-2 . The magnitude of the resulting pulsed electromotive force in the insulator-metal contact is recorded by the electrical circuit shown in FIG. 3.

The results of measurements of the time dependence of the response amplitude for different materials from which the galvanic pulsed x-ray sensor is made are shown in FIG. 4. From the consideration of the presented graphs, it follows that the rise time of the signal front (less than 4 ns), as a characteristic of the speed of the sensor to the impact of pulsed X-ray radiation, decreases when sapphire and quartz sensors are irradiated with pulsed X-ray radiation from the Z-pinch (FIG. 4) by compared to 40 ns for a sensor made in accordance with the prototype. Thus, the design of the proposed sensor, including the replacement of KU1 glass with single-crystal quartz or sapphire, leads to an increase in its speed by 10 times compared to the prototype.

EXAMPLE #2

The effect of the roughness of the front (working) surface of the sensor plate 2 was considered (Fig. 2). Sensors with quartz and sapphire plates were tested. From a consideration of the graphs in Fig. 5c and 5d it follows that there is an increase in their speed (the rise rate of the front is about 8 ns) when irradiated with pulsed X-ray radiation from the Z-pinch (Fig. 5) in comparison with sensors, which are characterized by a large roughness of the front (working) surface (speed rise of about 32 ns), as well as in comparison with sensors based on glass KU-1 (prototype) with uncontrolled surface roughness.

In addition, the galvanic signal from the sensor with a rough surface (Fig. 5b) clearly deviates from linearity with respect to the X-ray pulse (Fig. 5d)

The above information confirms the industrial applicability of the sensors of the proposed design.

Sources of information.

1. Kalashnikova V.I., Kozodaev M.S. Detectors of elementary particles. - M.: Science. 1966.

2. Dense Plasma Diagnostics, Ed. N.G. Basov. - M: Science. 1989.

3. Kornblum H.N., Slivinsky V.W. // Rev. Scient. Instrum. 1978. V. 49. No. 8. P. 1204.

4. RU 2640320 "Method of registration of pulsed ionizing radiation", IPC G01T 1/00, publ. 12/27/2017.

5. Zaitsev V.I., Barykov I.A., Kartashov A.V., Terentiev O.V., Rodionov N.B. Radiation-induced galvanic effect observed in the metal-dielectric interface // JTF Letters. - 2016. - T. 42. - Issue. 22. - S. 72-78.

Claims (3)

1. A galvanic sensor of pulsed X-ray radiation, containing a dielectric plate, on both sides of which electrical contacts are made, characterized in that the first contact along the radiation path is made in the form of an annular coating of gold 1-5 μm thick, the surface of the dielectric plate facing the annular coating , has a roughness R _z ≤1 nm, the second contact on the opposite side of the plate is made in the form of a continuous coating of gold with a thickness of 1-5 microns. 2. Galvanic sensor according to claim. 1, characterized in that the dielectric plate is made of quartz or sapphire, has a thickness of 200-300 microns. 3. Galvanic sensor according to claim 1, characterized in that the outer diameter of the annular coating is D=18-19 mm, and the inner diameter is d=14-15 mm.

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