RU124846U1 - ZEEMANOVSKY Slowdown of the atomic beam - Google Patents

Abstract

1. Zeeman atomic beam moderator containing an atomic beam source and an inhomogeneous magnetic field generating unit located along the axis of the atomic beam propagation, as well as a counterpropagating optical radiation source and an acousto-optic modulator, characterized in that between the output of the atomic beam source and the input of the inhomogeneous formation unit the magnetic field is an atomic beam chopper, the control input of which is connected to the first output of the control unit, the second output of which It is connected to the control input of the unit for generating an inhomogeneous magnetic field and to the control input of the counterpropagating optical radiation source, while the control unit is designed in such a way that the duration of the control pulses Ti T formed synchronously at the same time and with the same period at the first and its second outputs obey the condition T <T.2. The Zeeman atomic beam moderator according to claim 1, characterized in that the atomic beam chopper contains an actuating part made in the form of a rotating plate and a control part made in the form of a controlled magnetic transmission drive, the control input of which forms the control input of the atomic beam chopper. The Zeeman atomic beam moderator according to claim 1, characterized in that the oncoming optical radiation source comprises a stabilized laser source and a beam chopper connected in series, while the control input of the beam chopper forms the control input of the oncoming optical radiation source.

Description

The utility model relates to the field of quantum electronics and can be used in atomic beam frequency standards for atomic beams, for example rubidium or cesium.

The metrological characteristics of such frequency standards, in particular frequency reproducibility, frequency instability, etc., are determined by the width of the microwave transition line in the atoms of the working substance beam. To improve metrological characteristics, it is necessary to reduce the width of the atomic transition line, which is possible, for example, by slowing the speed of movement of atoms of a beam of a working substance (see [1] - F. Rile / Frequency Standards. Principles and Applications // M., Fizmatlit, 2009, p. 166-174).

Currently, the preparation of a beam of delayed (“cold”) atoms of a working substance from a heat beam formed by a heat source of an atomic beam is realized by the following three main methods.

In the first method, implemented, for example, in US patent [2] - US 6303928, H05H 3/02, 10.16.2001, there is a controlled outflow of beam atoms from a magneto-optical trap, the loading procedure of which can use, for example, preliminary cooling of atoms using a laser slowdowns. Atoms falling into the region of the combined action of light rays and an inhomogeneous magnetic field slow down when interacting with near-resonant light and condense in the region of the minimum value of the magnetic field modulus, i.e. in the center of the trap. The use of special geometry of cooling rays, for example, overlapping the central zone of one ray, allows a continuous flow of atoms cooled in the trap towards the registration zone.

The second method, described, for example, in [3] is But Seong Lee, Sang Eon Park, Taeg Yong Kwon, Sung Hoon Yang, Hyuck Cho / Toward a cesium frequency standard based on a continuous slow atomic beam: preliminary results // IEEE Trans. Instrum. Meas., Vol.50, 2001, pp.531-534, uses the deceleration of the atoms of a heat beam by the counter action of laser radiation. This compensates for the Doppler shift, changing due to interaction with optical radiation, performed in such a way as to keep the atoms in constant resonance with the laser radiation and thus ensure cooling efficiency. The specified compensation is realized by changing the frequency of the laser radiation as atoms pass through the interaction region.

The third method, described, for example, in [4] is P.N. Melentiev, P. A. Borisov and V. I. Balkin / Zeeman laser cooling of Rb-85 atoms in transverse magnetic field // Journal of experimental and theoretical physics. Vol.98, No.4, 2004, pp.667-677, uses a Zeeman moderator. In this case, to compensate for the Doppler shift, we use the change in the frequency of the optical atomic transition in the external magnetic field of the solenoid, which is inhomogeneous along the axis of propagation of the atomic beam. As a result, the Zeeman shift along the direction of propagation of the atomic beam compensates for the Doppler shift, which changes due to cooling of the atoms. To achieve continuous deceleration in the interaction region of the atomic beam with the field of optical radiation, the spatial change in the magnetic field must correspond to the gradient of the Doppler shift.

If v ₀ is the initial velocity of atoms in the beam, then the distance to a complete stop of atoms is:

,

,

- ускорение атомов в пучке (имеющее отрицательное значение).Where

- acceleration of atoms in the beam (having a negative value).

In the process of deceleration, the atomic velocity v (z) b to the point z along the direction of propagation of the beam is equal to:

Accordingly, the Doppler shift f _D (z) at the point z is equal to:

where λ is the wavelength of the radiation from a decelerating laser.

The gradient of the Doppler shift is equal to:

The spatial change in the frequency shift ω _B (z) due to the Zeeman splitting of atomic levels in a magnetic field B (z) is defined as

ω _B (z) = (m _i g _i -m _k g _k ) μ _B B (z) / ћ,

where: m _i , m _k are magnetic quantum numbers,

g _i > g _k — Landé factors for i, k magnetic sublevels;

ћ is the reduced Planck constant.

In the Zeeman moderator technique, the gradient of the Doppler shift due to cooling of the atoms should be equal to the gradient of the Zeeman splitting due to the spatial change in the magnetic field:

From this condition follows the spatial dependence of the magnetic field to compensate for the Doppler shift:

where B (z ₀ ) is the value of the magnetic field at the point z ₀ .

In this case, the initial value of the magnetic field should be selected from the condition for tuning the frequency of laser radiation near the maximum of the thermal distribution (or behind the maximum if the goal is to cool more atoms). The maximum acceleration that an atom can receive when interacting with a laser radiation field is:

=

/М,

=

/ M,

where: k = 2π / λ,

2γ is the natural line width of the atomic transition,

M is the mass of the atom.

Accordingly, the minimum distance L _min at which the heat beam can be stopped in time t _min is:

есть

there is

For a heat beam of rubidium atoms slowed down at a transition with a wavelength of λ = 780 nm and a lifetime of 27 ns, the minimum deceleration length is L _min = 75 cm, the cooling time t _c = 3.7 ms.

An example of the implementation of the Zeeman atomic beam moderator is the device presented in the patent [5] - US 8049162, H01S 1/00, H01S 3/00, H05H 3/02, 11/01/2011, Fig.5, selected as a prototype.

The Zeeman atomic beam moderator, selected as a prototype, contains an atomic beam source and an inhomogeneous magnetic field generating unit located along the axis of the atomic beam propagation, as well as a counterpropagating optical radiation source and an acousto-optic modulator that generates direct and biased rays at its output.

The inhomogeneous magnetic field formation unit consists of a solenoid designed to form an inhomogeneous magnetic field, and its power source operating in a continuous mode. The oncoming optical radiation source contains a stabilized laser source. An acousto-optic modulator is, for example, an assembly of two acousto-optic modulators deflecting beams in directions perpendicular to each other and to the axis of the system. Sections of the resulting trajectories of displaced rays in a plane perpendicular to the axis of the system are described by Lissajous figures. A direct beam is a zero diffraction order not deflected by an acousto-optic modulator.

The source of the atomic beam and the solenoid of the block forming the inhomogeneous magnetic field are located in a vacuum volume, the necessary degree of pressure in which is maintained by a vacuum pump. In the case when the acousto-optic modulator is moved outside the evacuated volume, the input of direct and offset beams generated by the acousto-optic modulator is carried out through the corresponding window. The source of counterpropagating optical radiation and the acousto-optic modulator are offset relative to the general axis of propagation of the atomic beam, which eliminates the deposition of beam atoms on the window through which the rays coming from the output of the acousto-optical modulator are introduced into the evacuated volume.

The prototype device operates as follows. A diverging atomic beam created by a thermal source of an atomic beam interacts with an optical radiation field formed by a counterpropagating optical radiation source. In this case, the optical radiation with which the atoms interact consists of a main laser beam directed towards the longitudinal axis of the beam and offset laser beams formed by an acousto-optic modulator and having transverse components. The final configuration of the optical radiation field is formed due to reflection from the inner surface of the solenoid, which is a mirror cone. As a result, at each spatial point of the beam, the atom interacts with a two-component optical field, the longitudinal component of which reduces the projection of the velocity of atoms on the axis of the system, and the transverse component collimates the atoms in the transverse direction.

To achieve resonant interaction between atoms in the beam and optical radiation, which provides a decrease in the longitudinal velocities of atoms, the method of changing the frequency of the atomic transition by applying a magnetic field that is inhomogeneous along the axis of the beam, i.e. Zeeman cooling method. Structurally, this is achieved through the use of a solenoid with a variable number of turns, which creates a magnetic field profile that is inhomogeneous along the axis of propagation of the atomic beam. The solenoid is winded by a hollow copper wire into which coolant is supplied under pressure.

The requirements for the size of the solenoid depend on the type of atoms, as well as on the initial and final beam velocities. In the prototype, the length of the solenoid varies from 20 to 50 cm, while the diameter of the inlet of the solenoid varies in the range from 2 to 25 cm, and the diameter of the outlet in the range from 2.5 to 45 cm. The power consumed by the solenoid is in range from 1 to 30 kW, the optimal power is 14 kW. Excess heat with such energy consumption is removed by water cooling of the system.

The obvious drawback of the Zeeman atomic beam moderator, selected as a prototype, is the significant size of the solenoid, and as a result - high energy consumption and the resulting need for water cooling. These factors make it impossible to use the prototype in systems with limited dimensions and power consumption, in particular in on-board systems.

The technical result, the claimed utility model is aimed at, is the creation of a Zeeman atomic beam moderator with reduced dimensions and energy consumption, which is achieved through the application of the proposed cyclic-pulse mode of operation.

The essence of the utility model is as follows. The Zeeman atomic beam moderator contains an atomic beam source and an inhomogeneous magnetic field generating unit located along the axis of propagation of the atomic beam, as well as a source of counterpropagating optical radiation and an acousto-optic modulator connected in series. Unlike the prototype, an atomic beam chopper is placed between the output of the atomic beam source and the input of the inhomogeneous magnetic field generation unit, the control input of which is connected to the first output of the control unit, the second output of which is connected to the control input of the inhomogeneous magnetic field formation unit and with the control input of the oncoming source optical radiation. Moreover, the control unit is designed in such a way that the duration of the control pulses and T _imp1 and T _imp2 , formed synchronously, at the same time and with the same period at its first and second outputs, obey the condition T _imp1 <T _imp2 .

In particular cases, the atomic beam chopper contains an executive part made in the form of a rotating plate and a control part made in the form of a controlled magnetic drive, the control input of which forms the control input of the atomic beam chopper, and the oncoming optical radiation source contains a stabilized laser source connected in series and a beam chopper, wherein the control input of the beam chopper forms the control input of the oncoming optical radiation source Eden.

The essence of the utility model and its feasibility are illustrated by illustrative materials presented in figures 1-3, where:

figure 1 presents the structural diagram of the proposed Zeeman moderator of the atomic beam;

figure 2 is a timing diagram explaining the cyclic-pulse nature of the Zeeman atomic moderator (2a is a diagram of control pulses u ₁ at the first output of the control unit, 2b is a diagram of control pulses and ₂ at the second output of the control unit, 2c is a diagram of current i _salt in the solenoid, 2d is a diagram illustrating the number of atoms N _am _ _in at the inlet of the solenoid, 2d is a diagram illustrating the number of atoms N _am _ _in at the outlet of the solenoid, 2e is a diagram illustrating the average atomic velocity v _am _ _Wed at the outlet of the solenoid );

figure 3. - dependences of the distribution of the number of atoms (n) over the velocities (ν) at the output of the solenoid in characteristic time periods (3a - for t = t ₀ , 3b - for t _i <t <t ₂ , 3c - for t ₃ >t> t ₂ )

The inventive Zeeman atomic beam moderator contains, see FIG. 1, an atomic beam source 1, a beam of 2 atoms, an atomic beam chopper 3 and an inhomogeneous magnetic field generating unit 4 located along the atomic beam propagation axis, as well as a counterpropagating optical source 5 radiation and an acousto-optic modulator 6, forming at its output a straight line 7 and offset 8 rays.

The control input of the atomic beam chopper 3 is connected to the first output of the control unit 9, the second output of which is connected to the control input of the inhomogeneous magnetic field generating unit 4 and to the control input of the oncoming optical radiation source 5. At the same time, the control unit 9 is designed in such a way that the duration of the control pulses T _imp1 and T _imp2 , formed synchronously, at the same time and with the same period at its first and second outputs, obey the condition T _imp1 <T _imp2 .

The atomic beam chopper 3 contains an actuating part made in the form of a rotating plate 10, periodically opening and closing the path for a beam of 2 atoms, and a control part made in the form of a controlled magnetic drive 11, the control input of which forms the control input of the atomic beam chopper 3. A controlled magnetic drive 11 provides a non-contact transmission of the rotational force to the rotating plate 10 located in the evacuated volume. An embodiment of the atomic beam chopper 3 with a rotating plate and a controlled magnetic transmission drive is presented, for example, in [6] - S.Ya. Khmel, R.G.Sharafutdinov / Time-of-flight measurements in a molecular beam isolated from a stream of condensing carbon dioxide // Zh.T.F., Vol. 68, No. 8, 1998, pp. 120-124.

Block 4 forming an inhomogeneous magnetic field consists of a solenoid 12, designed to form an inhomogeneous magnetic field, and a controlled power source 13, the control input of which forms the control input of block 4 of the formation of an inhomogeneous magnetic field.

The oncoming optical radiation source 5 comprises a stabilized laser source 14 and a beam chopper 15 connected in series, while the control input of the beam chopper 15 forms the control input of the oncoming optical radiation source 5. The beam chopper 15 can be made, for example, in the form of a two-pass acousto-optic modulator with a radiation-blocking fixed screen. The stabilized laser source 14 can be made, for example, in the form of a semiconductor laser stabilized by resonance of saturated absorption in an atomic medium, for example, similarly to the laser described in [7] - P. A. Borisov, PNMelentiev, SNRudnev, VIBalykin / Simple System for Active Frequency Stabilization of a Diode Laser in an External Cavity // Laser Physics, Vol. 15, No.11, 2005, pp. 1-5. External control of the laser source 14 is not required, but the scheme of its power supply and stabilization of parameters should include an algorithm for searching and capturing the resonance of saturated absorption. In practical schemes, it is advisable to use a composite source consisting of a low-power vertical emission laser (VECSEL) and a semiconductor laser amplifier as a laser source 14.

The source 1 of the atomic beam, the Executive part of the chopper 3 of the atomic beam and the solenoid 12 of the unit 4 for forming an inhomogeneous magnetic field are located in a vacuum volume with a vacuum pump 16.

In the case under consideration, the acousto-optic modulator 6 is outside the evacuated volume, while the rays formed by the acousto-optic modulator 6 are inputted through the corresponding window (not shown in Fig. 1).

In this case, the oncoming optical radiation source 5 and the acousto-optic modulator 6 are displaced, as in the prototype, relative to the general axis of propagation of the atomic beam 2, which eliminates the deposition of beam atoms on the window through which the rays 7 and 8 formed by the acousto-optic modulator 6 are introduced into the evacuated volume , which positively affects the resource of work. The asymmetry of the optical scheme that occurs in this case, namely, the slope of the beam 7 with respect to the axis of propagation of the beam of 2 atoms, is compensated by the asymmetry of the spatio-temporal distribution of the rays 8, similar to the prototype.

The acousto-optic modulator 6 is, for example, an assembly of two acousto-optic modulators deflecting beams 8 in directions perpendicular to each other and the axis of the system. Sections of the resulting trajectories of displaced beams 8 in a plane perpendicular to the axis of the system are described by Lissajous figures. In this case, the direct beam 7 represents the zero diffraction order, which is not rejected by the acousto-optical modulator 6.

Optical radiation at the input of the acousto-optical modulator 6 can be supplied either directly from the beam chopper 15 and the stabilized laser source 14, or using optical fiber (not shown in Fig. 1), which makes it possible to place the counterpropagating optical radiation source 5 in an arbitrary region of space in this case .

The operation of the claimed Zeeman atomic beam moderator is as follows.

An atomic beam source 1 (for example, a heat source of a rubidium atom beam) forms an atomic beam 2 at its output, which, through an atomic beam interrupter 3, enters the input of an inhomogeneous magnetic field generating unit 4, namely, the input of solenoid 12.

The control unit 9 generates at its first and second outputs sequences of control pulses u ₁ and u _{2 of} duration T _imp1 and T _imp2, respectively, where T _imp1 <T _imp2 . Control pulses are generated in synchronism, in the same initial time t ₀ and repeats with a periodicity of T · (2a, b).

The control pulses u ₁ are supplied to the control input of the atomic beam chopper 3 (i.e., to the control input of the controlled magnetic drive 11, which rotates the rotating plate 10), and the control pulses U2 are sent to the control input of the inhomogeneous magnetic field generating unit 4 (i.e. i.e., to the control input of the controlled power supply source 13 of the solenoid 12) and the control input of the oncoming optical radiation source 5 (i.e., to the control input of the beam chopper 15).

Under the action of the control pulse u ₂ through the winding of the solenoid 12 begins to flow current i _sol (pigv), under the influence of which in the inner space of the solenoid 12 is formed an inhomogeneous magnetic field.

Under the action of the control pulse u ₁ at time t _{0, the} atomic beam chopper 3 begins to pass the atomic beam 2 into the solenoid 12 (Figs. 2a, 3a), where it is simultaneously affected by an inhomogeneous magnetic field and the field of counterpropagating optical radiation.

At time t ₁ (Fig. 2a), the atomic beam chopper 3 closes, which leads to the interruption of the atomic beam 2. Due to this, fast beam atoms are the first to leave the solenoid 12 and collisions with them do not interfere with the cooling of the remaining atoms at lower speeds (Fig. 2d , e, e, 3b).

The optical radiation with which the atoms of the beam 2 interact, consists of a direct beam 7 directed towards the atomic beam 2, and displaced beams 8 having transverse components. The final configuration of the optical radiation field inside the solenoid 12 is formed due to reflection from the inner surface of the solenoid 12. As a result, at each spatial point, the atoms of the beam 2 interact with a two-component optical field, the longitudinal component of which reduces the projection of the velocity of atoms on the axis of the system, and the transverse component collimates atoms in the transverse direction. In this case, the magnetic field strength in each section of the solenoid 12 is selected so as to compensate for the Doppler frequency shift of the atomic resonance in the beam of flying atoms, and, thus, provide the most effective braking of the selected velocity group of atoms with the oncoming light beam along the entire length of the solenoid 12.

Unlike the prototype, the frequency of laser radiation (counterpropagating optical radiation) is initially tuned so as to ensure effective braking of not all atoms flying through the solenoid 12, but of the slowest part of them, having a speed ν≤ν ₀ (Fig.3b). These slow atoms, cooled in the solenoid 12 to speeds (1-10) m / s, begin to leave the solenoid 12 at time t ₂ (fig.2d, e). In this case, fast atoms, characterized by velocities ν≤ν ₀ , are not affected by interaction with light and by the time t ₂ = t ₁ + l / ν ₀ (hereinafter, l is the length of solenoid 12) leave the solenoid 12 (Figs. 2e, 3c). )

. Таким образом, при В_mах>>B_min рассеиваемая на соленоиде 12 мощность Р~l·(B_max+B_min)/2~

, и уже двукратное снижение скорости ν₀ приводит к 4-х кратному уменьшению длины соленоида 12 (что для теплового пучка атомов рубидия составляет 18,75 см), и к 16-ти кратному снижению рассеиваемой на нем мощности.A group of atoms having speeds ν≤ν ₀ is effectively cooled in the solenoid 12 by rays 7 and 8, similarly to the prototype. In this case, the required length l of the solenoid 12 is proportional to the square of the atomic velocity v ₀ : l ~ ν ₀ ² , and the maximum magnetic field at a constant gradient is proportional to the length l of the solenoid 12: V _max ~ I ~

. Thus, at В _max >> B _{min the} power Р ~ l · (B _{max +} B _min ) / 2 ~ dissipated on the solenoid 12

, and already a twofold decrease in the velocity ν ₀ leads to a 4-fold decrease in the length of the solenoid 12 (which is 18.75 cm for the heat beam of atoms of rubidium), and to a 16-fold decrease in the power dissipated on it.

The process of cooling the atoms ends at time t ₃ when the slow atoms, characterized by the velocity distribution shown in figv, leave the solenoid 12 (fig.2d, e). At this moment, the oncoming optical radiation source 5 is turned off and the power from the solenoid 12 is turned off (Fig.2b). After that, after a lapse of time t ₄ -t ₃ = T _ind <1 ms, determined by the inductance of the solenoid 12 and the internal resistance of the controlled power source 13, the slow atoms are in conditions free from any disturbing influences.

From time t ₄ until the end of the cyclic switching period of duration T, the decelerated beam atoms fly along the propagation axis that part of the space that is designed to "record" the parameters of the beam atoms.

The considered cyclic-pulse mode of operation provides the following.

Firstly, it helps to prevent the heating of slow atoms (ν≤ν ₀ ) by collisions with fast atoms (ν> ν ₀ ).

Secondly, it allows time separation of fast atoms that have passed solenoid 12 without braking and slow atoms cooled in solenoid 12 to speeds (1-10) m / s, and in the future use only slow atoms.

Thirdly, it allows several times to reduce the value of power dissipated on the solenoid 12.

Fourth, it makes it possible to exclude the perturbing effect of resonant optical radiation and the magnetic field of the solenoid on the subsequent process of measuring the resonant frequency of decelerated atoms.

Thus, in the inventive Zeeman atomic beam moderator, unlike the prototype, not all atoms are cooled, but only those whose speed does not exceed ν ₀ (fig.3b, c). When choosing ν ₀ <ν _cp , where ν _cp is the average, most probable, velocity of the heat beam atoms at the input of the solenoid 12, the length of the solenoid 12 can be reduced by (ν ₀ / ν _cp ) ² times in comparison with the prototype. This reduces the amount of cooled atoms, such as ν ₀ = ν _cp / 2 number of cooled atoms will be 2.65% of the total number of atoms in the beam, and at ν ₀ = ν _cp / 4 number of cooled atoms will be 0.18% of the total number of atoms in the beam. The indicated loss in the number of atoms in the metrological sense is compensated, firstly, by the possibility of their deep cooling to speeds (1-10) m / s, and a corresponding decrease in the width of the atomic resonance line, and secondly, by a high degree of isolation of the atomic transition from external influences.

The above shows that the claimed utility model is feasible and ensures the achievement of a technical result, which consists in creating a Zeeman atomic beam moderator with reduced dimensions and energy consumption.

So, in the practically significant case corresponding to the twofold decrease in speed considered above (ν ₀ = ν _cp / 2), the length of the solenoid 12 decreases by four times and amounts to only 18.75 cm for the beam of rubidium atoms.

In this case, the decrease in power dissipated by the solenoid 12, only by reducing the length of the solenoid 12 reaches sixteen times, and taking into account the cyclic-pulse mode of operation is even greater. Thus, the refrigeration cycle atoms (the time interval from t ₀ to t ₃₎ at a final velocity of the atoms of 1 m / s and the length of said solenoid 12 (18.75 cm) does not exceed 0.2. When the cycle period is equal to one second (T = 1 s), the average power dissipated on the solenoid 12 is further reduced by another six times. Thus, the power consumed by the solenoid 12 is only (100-200) W, which is significantly lower than in the prototype.

Information sources

1. F. Rile / Frequency Standards. Principles and applications // M., Fizmatlit, 2009, p.166-174.

2. US 6303928, H05H 3/02, publ. 10/16/2001.

3. But Seong Lee, Sang Eon Park, Taeg Yong Kwon, Sung Hoon Yang, Hyuck Cho / Toward a cesium frequency standard based on a continuous slow atomic beam: preliminary results // IEEE Trans. Instrum. Meas., Vol. 50, 2001, pp. 531-534.

4. P.N. Melentiev, P.A. Borisov and V.I. Balykin / Zeeman laser cooling of Rb-85 atoms in transverse magnetic field // Journal of experimental and theoretical physics, Vol. 98, No.4, 2004, pp.667 - 677.

5. US 8049162, H01S 1/00, H01S 3/00, H05H 3/02, publ. 11/01/2011, Fig. 5.

6. S.Ya. Khmel, R.G. Sharafutdinov / Time-of-flight measurements in a molecular beam isolated from a stream of condensing carbon dioxide // ZhTF, vol. 68, vol. 8, 1998, pp. 120-124.

7. P.A. Borisov, P.N. Melentiev, S.N. Rudnev, V.I.Balykin / Simple System for Active Frequency Stabilization of a Diode Laser in an External Cavity // Laser Physics, Vol.15, No. l1,2005, pp. 1-5.

Claims (3)

1. Zeeman atomic beam moderator containing an atomic beam source and an inhomogeneous magnetic field generating unit located along the axis of the atomic beam propagation, as well as a counterpropagating optical radiation source and an acousto-optic modulator, characterized in that between the output of the atomic beam source and the input of the inhomogeneous formation unit the magnetic field is an atomic beam chopper, the control input of which is connected to the first output of the control unit, the second output of which It is connected to the control input of the unit for generating an inhomogeneous magnetic field and to the control input of the oncoming optical radiation source, while the control unit is designed in such a way that the duration of the control pulses T _imp1 and T _imp2 , generated synchronously at the same time and with the same period at the first and second outputs obey the condition T _imp1 <T _imp2 . 2. Zeeman atomic beam moderator according to claim 1, characterized in that the atomic beam chopper comprises an actuating part made in the form of a rotating plate and a control part made in the form of a controlled magnetic transmission drive, the control input of which forms the control input of the atomic beam chopper. 3. Zeeman atomic beam moderator according to claim 1, characterized in that the oncoming optical radiation source comprises a stabilized laser source and a beam chopper connected in series, while the control input of the beam chopper forms the control input of the oncoming optical radiation source.

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