RU2317847C2 - Thallium isotopes separation method - Google Patents

Abstract

FIELD: processes of nuclear physics.

SUBSTANCE: method comprises steps of creating beam of thallium atoms, for example by heating metallic thallium in evaporation chamber till 600 - 660°C; providing equilibrium pressure of thallium vapor 1 - 10 Pa; simultaneously igniting gas discharge in order to realize first stage of thallium atoms excitement to meta-stable state due to creating beam of thallium atoms in excited meta-stable state; then realizing second stage of excitement by means of laser irradiation during two successive steps. At first stage thallium atoms in excited meta-stable state are excited by means of laser irradiation, for example with wave length 535 nm to resonance state. At second stage atoms of desired thallium isotope in excited resonance state are transferred to Rydberg state by means of laser irradiation, for example with wave length 444 nm. At both stages of excitement pulse mode of laser irradiation with pulse duration, for example 5 - 10 s is used. After multi-stage excitement atoms of desired isotope of thallium are ionized and extracted from beam due to applying cross electric field at supplying pulse voltage in mode limiting occurring of super-irradiation from levels corresponding to Rydberg state. Preferably, voltage value is in range 10 - 25 kV, pulse duration is in range 30 - 100 ns. The whole process is realized in vacuum whose level provides creation of processes necessary for separation of thallium isotopes.

EFFECT: lowered power consumption, improved quality parameters of laser beam.

19 cl, 3 dwg, 10 ex

Description

The invention relates to quantum electronics and laser technology and can be used in nuclear physics to separate isotopes.

A known method for the isolation of thallium isotopes (application W02004011129, IPC: 7 B01D 59/34 for the invention of “Method for Isotope Separation of Thallium” by Jeong Do-Young, Co. Kwang-Hoon, Lim Gwon, Kim Cheol-Jung, published 05.02.2004, .), which consists in creating vapors of thallium atoms, in the subsequent multi-stage excitation of the atoms of the required isotope by laser radiation, which includes the first stage in series - excitation by radiation with a wavelength of 378 nm of thallium atoms to the resonance state and their transition through spontaneous emission to the metastable state, the second stage - excited e atoms from the metastable state to the intermediate radiation with a wavelength of 292 nm, a third stage representing a photoionization radiation in the wavelength range of 700 to 1400 nm, and in a final step - removing ionized atoms of the desired isotope from the beam by an electrostatic collector.

The disadvantages of the technical solution include the high energy costs and low quality of the laser beam. High energy costs are due to the use of lasers with high output power. The low quality of the laser beam is a consequence of the need to convert radiation to the second harmonic. In addition, the well-known technical solution has a high cost due to the fact that the use of three laser beams for multi-stage excitation of atoms requires complex and expensive optical systems to combine them, as well as due to the use of two ultraviolet lasers in the method, the radiation of which is high cost due to their low efficiency.

The closest technical solution to the claimed one relates to a method for the isolation of thallium isotopes (Japanese Patent No. 20002628866, IPC: B01D 59/34, B01D 59/50 for the invention "Atomic Vaporizer Isotope Separation for 203 Thallium and 210 Lead Isotopes", by Scheibner Karl F., Christopher A. Heinamu, Michael A. Johnson, RFWordon, published September 26, 2000), which consists in creating a stream of thallium atoms, followed by multistage excitation of the atoms of the required isotope by laser radiation, which consistently includes the first stage - excitation of thallium atoms from the ground state in close to resonant y, the second step - the excitation of the intermediate to the final state, which is the Rydberg state, and in the final step - holding ionization desired isotope of thallium atoms through application of an electric field extraction of the desired isotope is ionized atoms from the beam.

The disadvantages of the technical solution include the high energy costs and low quality of the laser beam. High energy costs are due to the use of lasers with high output power. The low quality of the laser beam is a consequence of the need to convert radiation to the second harmonic. In addition, the known technical solution has a high cost, mainly due to the use of ultraviolet laser radiation in the wavelength region of 377.7 nm, which has a high cost.

The technical result of the invention is to reduce energy costs and improve the quality of the laser beam. The invention is also aimed at reducing costs.

The technical result is achieved by the fact that in the method for the isolation of thallium isotopes, which consists in the fact that they carry out multi-stage excitation of the atoms of the desired isotope, after which the atoms of the required isotope are ionized by applying an electric field and the ionized atoms are extracted from the beam, the multi-stage excitation of atoms of the required isotope is carried out in two stage, namely, first carry out the stage of excitation by gas discharge, and then the stage of excitation by laser radiation, which are carried out in vacuum, ha a level that ensures the occurrence of processes for the separation of thallium isotopes, while the stage of excitation by a gas discharge is carried out in the process of creating a beam of thallium atoms by evaporation of the thallium metal in the evaporation chamber and ignition of a gas discharge in it, by which the thallium atoms are excited into a metastable state, after which form in a vacuum, characterized by a level that provides processes for the separation of thallium isotopes, a beam of thallium atoms in an excited metal astable state and proceed to the implementation of the second stage.

In the method for creating a beam of thallium atoms and carrying out the stage of excitation by a gas discharge carried out in the process of creating a beam of thallium atoms, the evaporation chamber containing thallium metal is heated to a temperature ensuring the creation of an equilibrium pressure of thallium atom vapors in the evaporation chamber, and create an equilibrium vapor pressure of atoms thallium.

In the method, an evaporation chamber containing thallium metal is heated to a temperature of 600 ÷ 660 ° C and an equilibrium vapor pressure of thallium atoms equal to 1 ÷ 10 Pa is created.

In the method, the stage of excitation by laser radiation is carried out in two successive stages, at the first stage, thallium atoms in an excited metastable state, laser radiation with a wavelength that provides excitation of the atoms of the desired isotope into the resonance state, is excited to the resonance state, then to the second atoms of the required thallium isotope, which are in the excited resonance state, are excited by laser radiation with a wavelength that ensures the transition to Rydberg states Rydberg’s condition, in which the pulse mode is used at both levels of excitation by laser radiation, at the first stage, the duration of the radiation pulse is selected commensurate with the lifetime of the excited thallium atom in the resonance state and restricts the reverse transition to the metastable state, and at the second stage, the duration of the radiation pulse is chosen to limit the reverse transition to the downstream excited state from the Rydberg or resonant excited state and, therefore, is commensurate with time the life of an excited thallium atom in a resonant state.

In the method, at the first stage of the stage of excitation by atoms of the desired isotope by laser radiation, a wavelength of 535 nm is used in a pulsed mode with a radiation pulse duration of 5 to 10 ns, and at the second stage of the stage of excitation of laser atoms with radiation, a wavelength of 444 nm is used in a pulsed mode with a duration radiation pulse from 5 to 10 ns.

In the method, the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that provides processes for the extraction of thallium isotopes, by applying a transverse electric field, while applying voltage in a mode that limits the development of superradiation from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on the width of the zone of exposure to the laser nuclear radiation, the concentration of excited atoms of the desired isotope, and the proximity of Rydberg levels to the ionization boundary.

In the method, when ionizing the atoms of the desired isotope by applying an electric field and extracting ionized atoms from the beam, carried out by applying a transverse electric field, voltage is applied in a pulsed mode with a duration of 30 to 100 ns, with a voltage of 10 to 25 kV.

The invention is illustrated by the following description and the accompanying figures. Figure 1 presents a diagram of the energy levels of the thallium atom used, where 1 is the ground state, 2 is the metastable state, 3 is the resonance state, 4 is the Rydberg state, 5 are the ionic states of thallium atoms representing a continuous spectrum. Figure 2 schematically shows the evaporation chamber, where 6 is the body of the evaporation chamber, 7 is the rod, 8 is the tube, 9 is the reservoir for thallium, 10 is the gap, 11 is the heater, 12 is the flow of thallium atoms. Figure 3 schematically shows a thallium extraction unit, where 13 is a slotted diaphragm, 14 is an extraction zone, 15 is an anode, 16 is a cathode, 17 is a laser radiation exposure zone, 18 is a screen.

In the proposed method, multistage excitation of thallium atoms is carried out in two stages: excitation by a gas discharge, carried out in an evaporation chamber, in combination with excitation by laser radiation, carried out in a vacuum, characterized by a level that ensures processes for the extraction of thallium isotopes. At the first stage, thallium atoms are excited to a metastable state by ignition of a constant gas discharge in the evaporation chamber. The evaporation chamber (Figure 2) is made in the form of a housing (6) made of stainless steel or graphite and performing the function of a cathode during gas discharge, and placed inside the housing of the rod (7) made of stainless steel located in the tube (8) made from a dielectric material, for example, ceramic alumina, a thallium reservoir (9), a heater (11), in which a housing (6) with structural elements located therein is placed. In the housing (6), a slot (10) is made from above, with a width determined by the required process capacity and approximately 0.1 mm. The length of the evaporation chamber and, accordingly, the length of the slit are also determined by the required capacity.

The stream (12) of thallium atoms in an excited metastable state leaves the slot (10) and enters the input of the thallium separation site (Figure 3). At the entrance of the thallium separation unit, at least two slotted diaphragms (13) are made, which are designed to form a low-dispersing atomic beam. After the formation of the atomic beam, it enters the extraction zone (14) located between the anode (15) and the cathodes (16) and between the screen (18) made over the extraction zone (14) and the casing (6), and then into the impact zone laser radiation (17) located in the extraction zone (14) between the cathodes (16) and the anode (15). The evaporation chamber (Figure 2) and the thallium separation unit (Figure 3) are located in a vacuum chamber in which the vacuum is maintained at a level that ensures the necessary processes for the isolation of the required thallium isotope. The pressure characterizing the required vacuum level is not more than 10 ^-6 Pa, and 10 ^-8 ÷ 10 ^-6 Pa are actually used as the operating range.

The implementation of the method is as follows.

The housing (6) is heated with a heater (11) to a temperature at which, during the evaporation of thallium atoms, an equilibrium vapor pressure of thallium atoms arises in the evaporation chamber, sufficient to ignite a hollow cathode gas discharge, at which the thallium atoms are excited to a metastable state ( state 2, see Figure 1). The temperature at which the equilibrium vapor pressure of the thallium atoms is established is approximately 600 ° C, and the temperature range used, which is suitable for creating conditions for ignition of a constant gas discharge and excitation of atoms in a metastable state, is 600 ÷ 660 ° C. The equilibrium vapor pressure of thallium atoms is about 1 ÷ 10 Pa. After heating and evaporation of the thallium atoms, a gas discharge stage is carried out. The ignition of a gas discharge leads to the excitation of thallium atoms and changes the population of level 2 (Figure 1).

The population of level 2 (FIG. 1) (metastable state) due to the large cross section for the electron excitation of thallium atoms to level 2 from the ground state 1 is determined by the expression

N ₂ = N ₁ (g ₂ / g ₁ ) exp (-ΔE / (kT _e )) (1), where

N ₁ - level 1 population;

g ₁ - statistical weight of level 1, component 2;

g ₂ - statistical weight of level 2, comprising 4;

ΔЕ is the energy difference between levels 2 and 1, which is about 0.97 eV;

k is the Boltzmann constant;

T _e is the electron temperature.

When the value of T _{e is} greater than or of the order of 3 eV, which is typical for a vapor pressure of thallium 1 Pa, N ₂ = 1.45 N ₁ . That is, about 60% of thallium atoms are in an excited metastable state.

Next, after the formation of a low-diverging atomic beam, which completes the operation of creating a beam of thallium atoms, proceed to the implementation of the stage of excitation by laser radiation, carried out in a vacuum, characterized by a level that provides processes for the extraction of thallium isotopes, which consistently includes two stages of excitation by laser radiation (Figure 1) . At the first stage, thallium atoms in an excited metastable state, by laser radiation with a wavelength providing excitation of the atoms of the desired isotope into the resonance state, are excited to state 3. At the second stage, the atoms of the required thallium isotope in the excited resonant state are laser radiation with a length waves providing transition to Rydberg states are excited to state 4.

Thallium atoms, including excited ones, which are in a metastable state, with a concentration of n = 10 ¹⁴ cm ^-3 , flow through a gap 10 into a vacuum, characterized by a level that ensures the necessary processes for the isolation of the required thallium isotope, where, using diaphragms 13, a low-diverging atomic beam is formed in the extraction zone 14 (FIG. 3), which reaches the zone of exposure to laser radiation 17. In the first stage of excitation by laser radiation, radiation at a wavelength of 535 nm transfers the atoms of the desired isotope to oyanie 3 (resonance condition), and then in the second stage excitation laser light radiation at a wavelength of 444 nm atoms required isotope needs to state 4 (Rydberg state). Since at the first stage of the laser excitation stage the laser radiation is tuned only to the wavelength corresponding to the emitted isotope, for example, T1 203, another isotope, in particular, T1 205 is not excited to state 3 and state 4.

In order to avoid reverse transitions of atoms from excited states, a pulsed laser mode is used. The transitions of atoms from state 3 to state 2 are prevented by choosing the laser pulse duration commensurate with the lifetime of atoms in excited states, and thus limiting the reverse transitions. The lifetime of thallium atoms in the excited state 3 is about 10 ns, which means that the laser pulse duration should be from 5 to 10 ns. This value of the pulse duration is a typical value of the pulse duration of the generation of lasers on self-limited transitions.

The lifetime of the atoms of the desired isotope in Rydberg state (state 4, Figure 1) is hundreds of nanoseconds. However, to transfer atoms to state 4, the choice of the duration of a laser pulse is carried out not from the condition of its commensurability with the lifetime of atoms in a given excited state, but from the condition of transferring all the atoms of the required isotope to Rydberg state. Since the lifetime of the atom of the required isotope in the excited state 3 is about 10 ns, after which, if it does not go to state 4, it goes into state 2, then to transfer all the atoms of the desired isotope (for example, T1 203) to the Rydberg state, the pulse duration laser radiation should be limiting inverse transitions; At a wavelength of 444 nm, the pulse duration is of the order of 10 ns, that is, the same as when excited to the resonance state.

After the completion of the stage of excitation by laser radiation, the atoms of the required isotope are ionized in vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes by applying a transverse electric field and extracting the desired isotope. After the passage of the light pulse between the anode 15 and the cathodes 16, a voltage is applied in a mode that avoids the development of superradiance from the levels corresponding to the Rydberg state to the underlying levels. This is a pulse mode of voltage supply, with a pulse duration of 30 to 100 ns and a short rise front, up to 15 ns. The minimum rise time of the voltage pulse can be from 1 ns, however, a value of 15 ns is sufficient for this operation. In this case, the magnitude of the applied voltage U is determined by the distance l _k between the cathode and the anode (in the more general case, the width of the zone of exposure to laser radiation 17), the concentration of excited atoms, and the proximity of Rydberg levels to the ionization boundary δЕ _i . When δE _i = 0.1 eV, n = 10 ¹⁰ cm ^-3 and l _ka = 1 cm, the value of U is about 10 kV. In the method, the value of U can vary from 10 to 25 kV.

The excited atoms of the required isotope, which are in Rydberg states, are almost instantly ionized by the application of an electric field, the ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Unexcited atoms of other thallium isotopes cannot be ionized when an electric field is applied, so they continue to move in a straight line, reach screen 18 and settle on it, forming waste. After complete evaporation of thallium from the tank 9, the vacuum chamber is depressurized, the product collector and the waste collector are removed from it, the tank 9 is again filled with thallium and the cycle repeats.

Using a gas discharge allows using thi energy and an inexpensive direct current source to transfer thallium atoms from the ground state 1 to state 2 (Figure 1). Further excitation of atoms in state 3 is carried out using a Rodamine 101 dye laser pumped by a copper vapor laser. If the excitation is carried out from state 1 to state 3 using laser radiation, then it is necessary to use radiation from a Steril 8 dye laser pumped by a copper vapor laser, with its further conversion to the second harmonic. The effectiveness of this transformation in practice does not exceed 30%. The conversion efficiency of the radiation of a copper vapor laser into the radiation of Rhodamine 101 and Steril 8 dye lasers is approximately the same and amounts to 10%. Therefore, the use of a gas discharge to transfer thallium atoms from the ground state to a metastable state allows to reduce the required value of the copper vapor laser power by 3 times with the same performance of the proposed method and known methods, and also to refuse to use radiation conversion to the second harmonic, which improves the quality of the laser beam and increases the reliability of the system. All this, ultimately, reduces the cost of obtaining the final product - the required isotope of thallium.

As information confirming the implementation of the method, we give the following examples.

Example 1

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, an evaporation chamber containing metallic thallium is heated to a temperature of 600 ° C and an equilibrium vapor pressure of thallium atoms of 1 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535 nm, which ensures the excitation of the desired isotope into the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 10 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 10 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa. In this case, a voltage of 10 kV is applied in a pulsed mode with a duration of 30 ns and a rise front of 15 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 2

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, an evaporation chamber containing thallium metal is heated to a temperature of 620 ° C and an equilibrium vapor pressure of thallium atoms of 2 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535 nm, which ensures the excitation of the desired isotope into the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 7 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 7 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa. In this case, a voltage of 15 kV is applied in a pulsed mode with a duration of 50 ns and a rise front of 15 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 3

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by gas discharge, an evaporation chamber containing thallium metal is heated to a temperature of 660 ° C and an equilibrium vapor pressure of thallium atoms of 10 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535 nm, which ensures the excitation of the desired isotope into the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 5 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 5 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa. In this case, a voltage of 25 kV is applied in a pulsed mode with a duration of 100 ns and a rise front of 15 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 4

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, an evaporation chamber containing thallium metal is heated to a temperature of 620 ° C and an equilibrium vapor pressure of thallium atoms of 2 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.046 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonant state and restricting the reverse transition to a metastable state of 8 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.5 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 5 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa. In this case, a voltage of 13 kV is applied in a pulsed mode with a duration of 66 ns and a rise front of 12 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 5

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, the evaporation chamber containing thallium metal is heated to a temperature of 690 ° C and an equilibrium vapor pressure of thallium atoms of 10 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-8 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-8 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.046 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonant state and restricting the reverse transition to a metastable state of 10 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.5 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 12 ns.

Then carried out in a vacuum (vacuum chamber), characterized by a level of 10 ^-8 PA, the ionization of atoms of the desired isotope and the extraction of ionized atoms from the beam by applying a transverse electric field. In this case, a voltage of 18 kV is applied in a pulsed mode with a duration of 700 ns and a rise front of 14 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 6

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, an evaporation chamber containing metallic thallium is heated to a temperature of 600 ° C and an equilibrium vapor pressure of thallium atoms of 1 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 5.5 · 10 ^-5 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 5.5 · 10 ^-5 Pa, in two successive stages is carried out. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.046 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonant state and restricting the reverse transition to a metastable state of 10 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.5 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 8 ns.

Then carried out in a vacuum (vacuum chamber), characterized by a level of 5.5-10 ^-5 PA, the ionization of atoms of the desired isotope and the extraction of ionized atoms from the beam by applying a transverse electric field. In this case, a voltage of 20 kV is applied in a pulsed mode with a duration of 44 ns and a rise front of 11 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 7

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, the evaporation chamber containing thallium metal is heated to a temperature of 692 ° C and an equilibrium vapor pressure of thallium atoms of 10 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.06 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 10 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.51 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 10 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa. In this case, a voltage of 9 kV is applied in a pulsed mode with a duration of 28 ns and a rise front of 15 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 8

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, the evaporation chamber containing thallium metal is heated to a temperature of 692 ° C and an equilibrium vapor pressure of thallium atoms of 10 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 5.9-10 ^-5 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 5.9-10 ^-5 Pa, in two successive stages is carried out. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.06 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 8 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.51 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 10 ns.

Then carried out in a vacuum (vacuum chamber), characterized by a level of 5.9 · 10 ^-5 PA, the ionization of atoms of the desired isotope and the extraction of ionized atoms from the beam by applying a transverse electric field. In this case, a voltage of 26 kV is applied in a pulsed mode with a duration of 56 ns and a rise front of 15 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 9

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, an evaporation chamber containing thallium metal is heated to a temperature of 598.7 ° C and an equilibrium vapor pressure of thallium atoms of 1 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.06 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 10 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.51 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 12 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-6 Pa. In this case, a voltage of 13 kV is applied in a pulsed mode with a duration of 100 ns and a rise front of 12 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

Example 10

A beam of thallium atoms is created and multistage excitation of the atoms of the required isotope is carried out in two stages, namely, the stage of excitation by a gas discharge and the subsequent stage of excitation by laser radiation.

To create a beam of thallium atoms and to carry out the stage of excitation by a gas discharge, the evaporation chamber containing thallium metal is heated to a temperature of 692 ° C and an equilibrium vapor pressure of thallium atoms of 10 Pa is created. In the evaporation chamber, a constant gas discharge is ignited, and the evaporated thallium atoms are excited to a metastable state. After this, a beam of thallium atoms in an excited metastable state is formed in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa.

The stage of excitation by laser radiation in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa, is carried out in two successive stages. At the first stage of laser excitation, thallium atoms in an excited metastable state excite into resonance state with laser radiation with a wavelength of 535.06 nm, which ensures the excitation of the desired isotope to the resonance state, and a radiation pulse duration comparable with the lifetime of the excited thallium atom in the resonance state and restricting the reverse transition to a metastable state of 4.8 ns. At the second stage of laser excitation, thallium atoms in the excited resonance state are excited into the Rydberg state by laser radiation with a wavelength of 444.51 nm, which provides excitation to the Rydberg state, and a radiation pulse that limits the reverse transition to 8 ns.

Then, the atoms of the desired isotope are ionized and the ionized atoms are removed from the beam by applying a transverse electric field in a vacuum (vacuum chamber), characterized by a level of 10 ^-7 Pa. In this case, a voltage of 20 kV is applied in a pulsed mode with a duration of 70 ns and a rise front of 7 ns. Almost instantly, the atoms of the required isotope in Rydberg states are ionized, ions are accelerated towards the anode, which acts as a collector, and when it is achieved, they are deposited on it, constantly forming a useful product.

The inventive method is applicable to some other elements on which lasers are implemented on self-limiting transitions, in particular, these are barium, lead, gold, calcium, strontium, manganese atoms, as well as to elements that have lower metastable states, for example, noble gas atoms - helium, neon, krypton, xenon and most metal atoms.

Claims (19)

1. The method of separation of thallium isotopes, which consists in the fact that they carry out multi-stage excitation of the atoms of the desired isotope, after which the atoms of the desired isotope are ionized by applying an electric field and ionized atoms are removed from the beam, characterized in that the multi-stage excitation of atoms of the required isotope is carried out in two stages namely, the stage of excitation by a gas discharge is first carried out, and then the stage of excitation by laser radiation, which is carried out in a vacuum characterized by a level of in order to separate the thallium isotopes, the stage of excitation by a gas discharge is carried out in the process of creating a beam of thallium atoms by evaporation of the thallium metal in the evaporation chamber and ignition of a gas discharge in it, by which the thallium atoms are excited into a metastable state, after which they form in a vacuum characterized by a level that ensures the occurrence of processes for the isolation of thallium isotopes, a beam of thallium atoms in an excited metastable state and initiating a second stage. 2. The method according to claim 1, characterized in that to create a beam of thallium atoms and carry out the stage of excitation by a gas discharge, carried out in the process of creating a beam of thallium atoms, the evaporation chamber containing thallium metal is heated to a temperature ensuring the creation of equilibrium pressure in the evaporation chamber thallium atomic vapor, and create an equilibrium vapor pressure of thallium atoms. 3. The method according to claim 2, characterized in that the evaporation chamber containing metallic thallium is heated to a temperature of 600 ÷ 660 ° C and create an equilibrium vapor pressure of thallium atoms equal to 1 ÷ 10 Pa. 4. The method according to claim 1, characterized in that the stage of excitation by laser radiation is carried out in two successive stages, at the first stage, thallium atoms in an excited metastable state, by laser radiation with a wavelength providing excitation into the resonant state of the atoms of the desired isotopes, they are excited to the resonance state, then at the second stage the atoms of the required thallium isotope, which are in the excited resonance state, are emitted by laser radiation with a wavelength that ensures transition to the states of the idberg, they are excited into the Rydberg state, and the pulse mode is used at both stages of excitation by laser radiation, at the first stage, the duration of the radiation pulse is chosen commensurate with the lifetime of the excited thallium atom in the resonance state and restricts the reverse transition to the metastable state, and at the second stage, the duration of the radiation pulse choose limiting the reverse transition to the excited downstream state from Rydberg's excited state or resonant state and in connection with m comparable to the lifetime of the excited thallium atoms in a resonant state. '' 5. The method according to claim 2, characterized in that the stage of excitation by laser radiation is carried out in two successive stages, at the first stage, thallium atoms in an excited metastable state, by laser radiation with a wavelength providing excitation of the desired atoms into the resonance state isotopes, they are excited to the resonance state, then at the second stage the atoms of the required thallium isotope, which are in the excited resonance state, are emitted by laser radiation with a wavelength that ensures transition to the states of the idberg, they are excited into the Rydberg state, and the pulse mode is used at both stages of excitation by laser radiation, at the first stage, the duration of the radiation pulse is chosen commensurate with the lifetime of the excited thallium atom in the resonance state and restricts the reverse transition to the metastable state, and at the second stage, the duration of the radiation pulse choose limiting the reverse transition to the excited downstream state from Rydberg's excited state or resonant state and in connection with m comparable to the lifetime of the excited thallium atoms in a resonant state. 6. The method according to claim 3, characterized in that the stage of excitation by laser radiation is carried out in two successive stages, at the first stage, thallium atoms in an excited metastable state, by laser radiation with a wavelength that provides excitation of the desired atoms into the resonance state isotopes, they are excited to the resonance state, then at the second stage the atoms of the required thallium isotope, which are in the excited resonance state, are emitted by laser radiation with a wavelength that ensures transition to the states of the idberg, they are excited into the Rydberg state, and the pulse mode is used at both stages of excitation by laser radiation, at the first stage, the duration of the radiation pulse is chosen commensurate with the lifetime of the excited thallium atom in the resonance state and restricts the reverse transition to the metastable state, and at the second stage, the duration of the radiation pulse choose limiting the reverse transition to the excited downstream state from Rydberg's excited state or resonant state and in connection with m comparable to the lifetime of the excited thallium atoms in a resonant state. 7. The method according to claim 4, characterized in that at the first stage of the stage of excitation by the laser radiation of the atoms of the desired isotope, use a wavelength of 535 nm in a pulsed mode with a pulse duration of 5 to 10 ns, and at the second stage of the stage of excitation by laser radiation radiation with a wavelength of 444 nm in a pulsed mode with a radiation pulse duration of 5 to 10 ns. 8. The method according to claim 5, characterized in that at the first stage of the stage of excitation by the laser radiation of the atoms of the desired isotope, radiation of 5 to 10 ns is used, and at the second stage of the stage of excitation of the laser radiation using radiation with a wavelength of 444 nm in a pulsed mode with a pulse duration of radiation from 5 to 10 ns. 9. The method according to claim 6, characterized in that at the first stage of the stage of excitation by atoms of the desired isotope by laser radiation, the wavelength of 535 nm is used in a pulsed mode with a radiation pulse duration of 5 to 10 ns, and at the second stage of the stage of excitation by laser radiation, radiation with a wavelength of 444 nm in a pulsed mode with a radiation pulse duration of 5 to 10 ns. 10. The method according to claim 1, characterized in that the ionization of atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes, by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 11. The method according to claim 2, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes, by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 12. The method according to claim 3, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes, by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 13. The method according to claim 4, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes, by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 14. The method according to claim 5, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and the extraction of ionized atoms from the beam is carried out in a vacuum characterized by a level that ensures the flow of processes for the isolation of thallium isotopes by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 15. The method according to claim 6, characterized in that the ionization of atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum characterized by a level that ensures the flow of processes for the isolation of thallium isotopes by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 16. The method according to claim 7, characterized in that the ionization of atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum characterized by a level that ensures the flow of processes for the isolation of thallium isotopes by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 17. The method according to claim 8, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum, characterized by a level that ensures the flow of processes for the isolation of thallium isotopes, by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 18. The method according to claim 9, characterized in that the ionization of the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam is carried out in a vacuum characterized by a level that ensures the flow of processes for the isolation of thallium isotopes by applying a transverse electric field, apply voltage in a mode restricting the development of superradiance from levels corresponding to Rydberg state, and the magnitude of the transverse electric field is determined based on Irene footprint of laser radiation, the density of excited atoms required isotope levels and proximity to the ionization of the Rydberg boundary. 19. The method according to any one of paragraphs.10-18, characterized in that when ionizing the atoms of the desired isotope by applying an electric field and extracting the ionized atoms from the beam, carried out by applying a transverse electric field, voltage is applied in a pulsed mode with a duration of 30 to 100 ns , with a voltage value of 10 to 25 kV.

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