Generator subnanosecond electron beams

 

The invention relates to the field of forming and generating charged particle beams and can be used in cathodoluminescence the analysis of matter, plasma, quantum electronics, etc. Generator subnanosecond electron beams containing gas diode and a generator of nanosecond pulses with 1 obostriteliv arrester, high-voltage terminal 3 which is connected to the cathode 4 of the gas diode. The anode 5 of the gas diode made of foil or mesh, with flat or with a large radius of curvature than that of the cathode. According to the invention, the capacitive drive generator made in the form of a short form of the line with a pulse duration in a coordinated load no more than 1 NS. The inductance of the discharge circuit and the surface of the insulator 6 of the gas diode made minimally sufficient for the fed to gas diode voltage. This abstrusely discharger has a response time less than 1 NS, and the gas pressure in the diode is 1 atmosphere or higher. In addition, the electron beam generator, the first output 2 botricello spark gap is made in the form of a cylindrical Cup, forming between the generator housing 7 and the outer surface of the output gap coaxial line , in the form of a rod, forming with the inner surface of the first output of the second coaxial line with a large wave impedance, and ending with the cathode, is made in the form of convex tablets of graphite, is placed in a metal frame. Effect: formation of high-energy (hundreds of Kev) subnanosecond flow of electrons (t1 NS) current density tens of amperes per cm2in the gas diode atmospheric pressure and above. 1 C.p. f-crystals, 1 Il.

The invention relates to the field of forming and generating beams of charged particles n can be used in cathodoluminescence the analysis of matter, plasma, quantum electronics and so on

A method of obtaining subnanosecond beams of high-energy electrons in vacuum and output it through the foil on the basis of the high-voltage pulse-periodic generators subnanosecond range [1]. The design of such generators in addition to the traditional elements includes subnanosecond modulator that generates picosecond voltage pulses. This design solution has allowed us to implement accelerators subnanosecond Puchko who is the generator of electrons [2]. In this generator the voltage source is a high voltage pulse transformer in the circuit of the secondary winding which is in series with the camera is the high-pressure spark gap. Bit capacity formed by the casing of the generator and the housing of the arrester high pressure, about 40 pF, the resistance shunting the discharge chamber, 200 Ohms. The high-pressure spark gap had the function of obotrites front of the pulse voltage. The amplitude of the pulse voltage has reached 160-180 kV and was determined by the breakdown voltage of a spark gap. As cathodes were used polished rods of tungsten alloy with a diameter of 12-14 mm with radii of curvature of the hemispherical working surface r=3-7 mm. In separate experiments on the working surface of the cathode was applied notches to increase the electric field at the surface. The anode was aluminum foil of a thickness of 8-15 μm. The interelectrode distance was 10-15 mm In gas-filled gap between the electrodes was carried out volume pulsed high-voltage discharge at a pressure of 10-2-760 Torr, which shaped beam of runaway electrons (RES). The maximum yield of electrons was obtained at a pressure medium 20-40 Torepresent, i.e. discharge voltage in the interval many times greater than the voltage of the static breakdown. The electric field in the discharge gap is non-uniform and is much stronger near the cathode. In the near-cathode area ratio of field strength to the gas pressure E/P is comparable with the maximum energy loss. In this field there is a transition of low-energy electron discharge mode of escape, with the result that they, speeding, leaving the near-cathode region and is formed beam vysokoenergeticheskikh electrons.

The disadvantage of the prototype is small the number of electrons and the limit on the lifetime of the electron beam t2 NS.

The objective of the invention is to increase the yield of electrons N. the reduction in the duration of the electron beam to the sub-nanosecond units.

The technical result of the invention is the formation of vysokoenergetichnykh (hundreds of Kev) subnanosecond flow of electrons (t1 NS) current density tens of amperes per cm2in the gas between atmospheric pressure and above.

The technical result is achieved by the fact that the generator subnanosecond electron beams, sod which is connected to the cathode gas diode, the anode gas diode made of foil or mesh, with flat or with a large radius of curvature than that of the cathode according to the invention, the capacitive drive generator made in the form of a short form of the line with a pulse duration in a coordinated load no more than 1 NS, the inductance of the discharge circuit and the surface of the insulator gas diode made minimally sufficient for the fed to gas diode voltage, while abstrusely discharger has a response time less than 1 NS, and the gas pressure in the diode is 1 atmosphere or higher.

In addition, the electron beam generator one conclusion botricello spark gap is made in the form of a cylindrical Cup, forming between the generator housing and the outer surface of the output gap coaxial line with a small wave impedance and the main power stock, and the second output coaxial first and made in the form of a rod, forming with the inner surface of the first output of the second coaxial line with a large wave impedance and ending with the cathode, is made in the form of convex tablets of graphite, is placed in a metal frame.

In Fig.1 presents a block diagram of the generator subnanosecond vs the s pulses with 1 obostriteliv discharger 2, the high-voltage terminal 3 which is connected to the cathode 4 of the gas diode. Gas filled diode molecular or atomic gas or gas mixture. The anode 5 of the gas diode made of foil or mesh flat or with a large radius of curvature. The cathode 4 is made with a radius of curvature smaller than the anode. Capacitive drive generator made in the form of a short form of the line with a pulse duration in a coordinated load no more than 1 NS inductance discharge circuit and the surface of the insulator 6 of the gas diode is minimally sufficient for the fed to gas diode voltage. In the generator set abstrusely discharger with response time less than 1 NS, the gas pressure in the diode is 1 atmosphere or higher, with one output high voltage botricello of the high-pressure spark gap is made in the form of a cylindrical Cup 2, forming between the generator housing 7 and the outer surface of the output gap coaxial line with a small wave impedance and the main power stock, and the second conclusion is made in the form of a rod 3, which is on the axis of the first pin forming with the inner surface of the first output of the second coaxial line with a large wave coprative.

The device operates as follows. The pulse generator 1 charges formiruemoyu line formed by the generator housing 7 and the housing of the spark gap 2, which commutes with the spark gap through the transmitting line formed by the output of the spark gap and the body of the gas diode, the voltage pulse on the gas diode.

The formation of subnanosecond electron beam is at the front of nanosecond voltage pulse, the beam is formed between the moving front pulsed volume discharge and anode. The velocity distribution of the plasma from the cathode is determined by fast electrons emerging from the cathode by increasing zero at the cathode and cathode spots.

Using the pulse generator, designed to be placed in short form lines with pulse duration in a coordinated load no more than 1 NS, the inductance of the discharge circuit and the surface of the insulator gas diode minimally sufficient for the fed to gas diode voltage and use botricello discharger with response time less than 1 NS and a cathode made in the form of a convex tablets of graphite, is placed in a copper frame, helped to form somnabulism discharge the main part of the runaway electrons with low initial values of the parameter E/p~0.1 kV/cm×Torr (E - the electric field strength, p is the gas pressure) is formed in the space between the plasma, which is formed at the cathode and anode. Cathode plasma with high speed distributed to the anode, due to the redistribution of the electric field in the portion of the gas diode is achieved critical value of E/p, including due to the geometric factor.

Design, which is implemented subnanosecond electron beam in discharge under atmospheric pressure, included a pulse generator with an impedance of 30 Ohms, the voltage at the agreed load ~200 kV, duration at half-height of ~3 NS pulse voltage of ~1 NS [3]. With this generator was used a gas chamber filled with air or nitrogen at a pressure of 760 Torr, and used two cathode. One cathode was a set of three cylinders of Ti foil thickness of 50 μm, is inserted into each other and mounted on aluminum substrate with a diameter of 36 mm, the Other the cathode was made of graphite in the form of tablets with a diameter of 29 mm, the edges were rounded and convex side facing towards the foil with a radius of curvature of 10 cm Graphite cathode was placed on a copper holder with a diameter of 30 mm O e PU the anode - the cathode was 18-28 mm Electron beam at a pressure of one atmosphere was obtained in air, nitrogen, helium and a mixture of CO2-N2Not as in one shot mode, pulses and repetition rate up to 10 Hz. The amplitude of the current in the air was 40 And Not 300 A. For the other gases also received the highest currents for similar conditions in the gas diode. The maximum distribution of the electron beam energy for the ring-shaped cathode when the air pressure in the diode (1 atmosphere) corresponded to the electron energy ~(90-110) Kev, the duration of the beam current for all subjects gases was less than 1 NS. For air at atmospheric pressure when using a generator with an impedance of 20 Ohms and a voltage pulse with an amplitude of up to 220 kV and duration at half-height of ~2 NS, when the pulse voltage is ~0.3 NS was obtained pulse duration of the beam current of 0.3 na current 70 A, the maximum of the energy distribution of the electrons was ~110 Kev [4].

Sources of information taken into account.

1. Aladdin M. I., Shpak Century, a Powerful small-periodic-pulse generators subnanosecond range. Instruments and experimental techniques. 2001, No. 3, S. 5-31. 2. L. C. Tarasova, L. N. Khudyakov, I. C. L. Loiko, C. A. Zuckerman. Fast electrons and rentgenovsk, so XLIV, B. 3, C. 564-568. 3. Alekseev S. B., Bauman C. M., Tarasenko C. F. Beam of electrons generated in the gas-filled diode at atmospheric pressure air and nitrogen. Technical physics letters. 2003, T. 29, vol.10, S. 29-35. 4. Tarasenko C. F., Yakovlenko S. I., Orlov C. M., A. Tkachev I. Shumilov C. A. reception of powerful electron beams in dense gases. JETP letters. 2003, T. 77, vol.11, S. 737-742.

Claims

1. Generator subnanosecond electron beams containing gas diode and a generator of nanosecond pulses with obostriteliv arrester, high-voltage terminal of which is connected to the cathode gas diode, the anode gas diode made of foil or mesh, with flat or with a large radius of curvature than that of the cathode, characterized in that the capacitive drive generator made in the form of a short form of the line with a pulse duration in a coordinated load no more than 1 NS, the inductance of the discharge circuit and the surface of the insulator gas diode made minimally sufficient for the fed to gas diode voltage, while abstrusely discharger has a response time less than 1 NS, and the pressure of the gas in the diode is 1 atmosphere or higher.

2. Generator subnanosecond practical Cup, forming between the generator housing and the outer surface of the output gap coaxial line with a small wave impedance and the main power stock, and the second output is coaxial with the first and is made in the form of a rod, forming with the inner surface of the first output of the second coaxial line with a large wave impedance, and ending with the cathode, is made in the form of convex tablets of graphite, is placed in a metal frame.



 

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