Method and apparatus for neutron doping of substance

FIELD: chemistry.

SUBSTANCE: method for neutron doping of a substance involves slowing down fast source neutrons with a retarder substance, forming a stream of slow neutrons in a selected region and irradiating the substance to be doped with the slow neutrons. During the slowing down process, the fast source neutrons are separated according to propagation angles thereof; streams thereof moving a direction selected by the structure of the retarder substance are selected; streams selected by the structure are summed up, formed into a narrow band and directed onto the substance to be doped, which is controllably moved in the focal region of the neutron streams.

EFFECT: high efficiency of the doping process and forming regions with high degree of doping in given areas of the doped substance.

5 cl, 3 dwg, 3 ex

 

The technical field

Group of inventions relates to the technology of neutron transmutation doping (NTD) of silicon by thermal neutrons, which are widely used in the technology of electronic devices and electrical industry.

Prior art

The prior art method of obtaining nuclear-doped silicon, n-type, described in patent RU 2145128 published 27.01.2000, including slow fast neutron source substance moderator, the formation of thermal neutron flux and irradiation by thermal neutrons block LEGIROVANNOGO substances enriched in the isotope of silicon 30. The disadvantages of this method include radiation violations LEGIROVANNOGO substances with fast neutrons and the inability to increase the flux density of the alloying thermal neutrons in selected areas LEGIROVANNOGO substances.

The closest to the essential features of the claimed invention is a method of neutron transmutation doping of silicon, is described in patent RU 2089011 published 27.08.1997, including the reciprocating movement of the container with bars through the exposure zone of the reactor channel and control averaged over the length of the bars in the container fluence of neutrons, characterized in that in the pre-Cana is Les reactor form a neutron field and along the channel (x-axis) select plot - a≅x≅a, on which the density distribution of thermal neutron flux is an even function (f(x) f(x)), the container is placed ingots of silicon a total length not exceeding the length of the selected area channel (2a), and in the process of irradiating the container with the bars to be moved along the channel from one extreme position in which the bars in the container located outside the irradiation zone, in another, in which the middle of the length of the bars combined with the middle of the selected area in the channel (x=0), and after irradiation half-fluence correct the irradiation process is interrupted, the container deploy, swapping its ends, and similarly doublecut container remaining fluence of neutrons. The disadvantages of this method include radiation violations LEGIROVANNOGO substances with fast neutrons and the inability to increase the flux density of the alloying thermal neutrons, in selected areas LEGIROVANNOGO substances.

The prior art is also known a device for the production of nuclear-doped silicon, disclosed in the patent RU 2193610 published 27.11.2002, including an external source of fast neutrons, a moderator, block LEGIROVANNOGO substances enriched in silicon isotope 30, the moving device LEGIROVANNOGO substances, which essential features is the closest to the requested image is in the shadow. The disadvantages of this device include radiation violations LEGIROVANNOGO substances with fast neutrons and the inability to increase the flux density of the alloying thermal neutrons, in selected areas LEGIROVANNOGO substances.

The original state of the prototype is the irradiation channel of the reactor thermal neutrons, a cylindrical billet of silicon enriched isotope30Si. Under the influence of thermal neutrons in silicon reactions proceed:

As a result of this reaction is a radioactive isotope31Si, with the collapse of which there is an accumulation31P (phosphorus-31) - donor dopant that generates the n-type conductance. It is important that phosphorus is born in the lattice of the silicon.

In the method adopted for the prototype, produce the irradiation of large pieces of silicon placing them in the channel of any industrial or research reactor and keeping them there until the set of integral neutron flux required to obtain a desired electro-physical parameters of silicon. While the material in the channel rotating and reciprocating move to distribute in her body lagerweij impurities. But for some subjects, the electronics need a more complex distribution LEGIROVANNOGO the FOSFA the RA in the workpiece, than just a uniform.

Disclosure of inventions

The task, which directed the claimed group of inventions is to develop a method and device that improves thermal neutron flux in selected areas LEGIROVANNOGO substances and increasing the ratio of this thread to the background of fast neutrons in them.

The technical result achieved during the implementation of a group of inventions is the productivity growth process of doping and the formation of areas with a high degree of alloying in given areas LEGIROVANNOGO substances that can improve the quality and expand the technical capabilities of electronic elements and electronic devices that are created when the application doped by neutron matter.

This technical result is achieved due to the fact that in the method of neutron doping substances, including the slowing down of fast neutrons source substance moderator, the formation of thermal neutron flux in the selected area and the irradiation by thermal neutrons LEGIROVANNOGO substances, fast neutron source in the process of slowing sephirot in the corners of their distribution, allocate their streams moving in the selected substance structure of the retarder direction, summarize selected structure flows, is formed in the form of narrow is not and sent to lagerware substance, lagerware substance manageable move in the focus area neutron fluxes.

This technical result is also achieved due to the fact that the device for neutron doping substances, comprising a source of neutrons, a moderator, lagerware substance and the moving device LEGIROVANNOGO substances, the retarder is a device of forming a directed stream of neutrons, made in the form of long anisotropic plates with structured selectivity structure with channels between them, oriented in a dedicated structure, the directions of the field focuses the flow of neutrons and lagerware substance, at least its part placed in the region of tricks neutron fluxes, and the moving device LEGIROVANNOGO substance containing the controlled actuator and control system moving into the focus area. This selectivity of the structure of the retarder can be performed either in the form of packets slab longitudinal wedge-shaped plates so that their educated wedge-shaped channel with its axis oriented in the direction of the field focuses the flow of neutrons, or in the form of groups of curved plates of variable curvature, such that formed between them a curved channels in areas with minimum curvature oriented in the direction of the field of tricks is Otoko neutrons, or selectivity of the structure can be made so that the plate LEGIROVANNOGO substances placed in the channels between the fins of the retarder, and the plate can be both flat and profiled, for example, curved with variable curvature, so that the maximum radius of curvature is the center of the plate.

The possibility of the method due to the fact that the behavior of neutrons in the moderator, outside of the retarder and the interface are significantly different.

The essence of this method lies in the fact that at the beginning of a substance moderator of fast neutrons slow down, transferring their excess energy to the nuclei of matter in the process of scattering them. Then, when the execution of the structured retarder and anisotropic, in the form of long thin corrugated plates with channels formed between them, neutrons, moving along the channels from the depths of the moderator, take in the direction of areas where lagerware substance.

Thus, streams of neutrons, otsilindrovannye structure from different places in the body of anisotropic moderator and from different channels of the structure, summarize in the focus area neutron fluxes on legroom substance than increase the intensity of the neutron flux in them. The neutrons released from LEGIROVANNOGO matter without interacting with it, continue diffuse DV is laid before re-entering the retarder and then return again in the process of separation of the substance and structure of the retarder. For the correction process of doping in selected areas of silicon wafers required integral neutron flux, lagerware substance manageable move relative to the area of focus neutron fluxes, the structure of the moderator.

The method is carried out in the device for neutron doping substances, comprising a source of neutrons, a moderator, lagerware substance, the moving device LEGIROVANNOGO substances, characterized in that the retarder is made in the form of the anisotropic-structured device forming a directional neutron flux containing selectivity of the structure of the extended plates with channels between them, oriented in a dedicated structure, the directions of the field focuses the flow of neutrons and lagerware substance, at least its part placed in the region of tricks neutron fluxes, and the moving device LEGIROVANNOGO substance containing the controlled actuator and control his movements.

A possible embodiment of the device, characterized in that the structure of the retarder in the form of packets slab longitudinal wedge-shaped plates so that their educated wedge-shaped channel with its axis oriented in the direction of the field focuses the flow of neutrons.

Pay attention to the patterns of output Nate the ones of the slotted wedge-shaped structures, first, without taking into account the subtleties of the interaction of neutrons with the surface of the wedge-shaped slits. Considering that the neutron flux of each element of the surface of the wedge is equal to the neutron flux from the surface of the block and isotropic on the scattering angle 2π, but is limited by the exit angle of the wedge α, prointegrirowany the neutron flux over the surface of the wedge, and assigning it to a square slit get that flow from the gap is equal to the flow from the surface of the block. But there was a new quality - the flow from the gap is narrow. Therefore, combining narrow streams from a population similar to the slot neutron sources, and geometrically reducing these flows in the selected area, you can increase the overall density of the neutron flux in this area.

So, on the package of Ns wedge plates stream in a dedicated structure can be increased in Ks=2×(Ns-1) time (see Fig.2).

If along the Central axis of the package and across the planes of the package, put a few thin flat plates LEGIROVANNOGO silicon, and instead of a single plate pack shaper neutron flux to use a group of such packages, in this case, it is possible to form a number of narrow transverse lines with high density impurity concentration of phosphorus in them. The width of the lines and the ratio between them depends on the ratio of the dimensions of the wedge-shaped bands such distance lagerweij plate. A set of integral neutron flux lagerway plate30Si can be deployed at 90 degrees to form a lattice impurities of phosphorus in it.

It is possible for the structure of the retarder in the form of packets slab longitudinal wedge-shaped plates so that their educated wedge-shaped channel with its axis oriented in the direction of the field focuses the flow of neutrons and plate packs moderator on the right side of the plate LEGIROVANNOGO substances, and plate packs moderator, placed to the left of the plate LEGIROVANNOGO substances made mutually perpendicular. As a result, we get a square matrix of the rulers of the doped substance on the silicon wafer. In the lattice degree of doping remains increased Ks - fold in comparison with the background, and the linear sections of the lattice degree of alloying half. The share background of fast neutrons in the region of the rulers falls into ξ=1/Ks times.

Since the moving device LEGIROVANNOGO substance containing the controlled actuator and control system moving, changing position lagerweij plates relative to the lattice formed of wedge-shaped plates moderator, you can change the duty cycle width direction and the integral neutron flux in the areas of doping substances.

Possible VA is int the implementation of the device, characterized in that the structure of the retarder is made in the form of a slot group of the curved plates of variable curvature, such that formed between them a curved channels are oriented in the direction of the field focuses the flow of neutrons.

In this case, the similar patterns for selection of neutrons is substantially determined by neutron reflection from the surface of the wafer selectivity patterns.

First of all, let us note that for total external reflection of neutrons from the surface it is necessary that the transverse component of the kinetic energy of the neutron at the surface was less than the mean potential energy of repulsion of neutrons in the environment, which can be defined as the boundary energy of the neutrons in the environment.

You can report the following table for the edge energy Egthe boundary wavelength λgand cross-boundary velocity neutrons Vgfor different substances on the surface moderator:

Table 1
SubstanceEg, newλgnmvgm/s
Al0.543.22
Cu1.6869.85.67
C (graphite density of 2 g/cm3)1.7368.75.67
Be2.43586.81
BeO (2.9 g/cm3)2.6255.87.08
D2O (1.105 g/cm3)1.6670.25.63
Gr. steel HT1.8267.05.90
Glass0.995.34.15
Lead0.8796.94.08

In this case the angle of total external reflection is determined by the ratio of boundary velocity of the neutron vgto the velocity of a thermal neutron v0=2200 m/s,φs 360vgpv0. This angle is φs=10' to the surface of the graphite, φs=12' to the surface of beryllium, φs=10.7' to the surface of iron, φs=11.5' to the surface of Nickel and φs=9.5' to the surface of the copper. The angle of total reflection of neutrons can be increased by lowering the temperature of the retarder down to 4.2 K, and increase to units of degrees when applied to the surface supersonically coatings. Superthermal represent the layered structure of layers with different optical potentials applied to any substrate. For example, it may be a multilayer system from a wide barrier and 12 thin periodic layers of FeCo-Si. Possible neutron polarizing superthermal, efficiency neutron reflection which depends on the magnitude and direction imposed on the mirror, for example, CoFe(V)TiZr, magnetic fields.

It is essential that the neutrons emerging from the surface of a substance, receives additional energy equal to Egrand this gets an additional transverse velocity equal to vgdeflecting the trajectory from the surface, and the neutron. included in the substance loses this energy and speed. So flat extended R is nomeny channel has no selectivity neutrons properties. For the same reason, does not possess such properties and extended channel having a constant curvature of its surface, if the value of the boundary energy on the surface is constant.

To slotted channel got the ability to selectively capture moving neutrons in it, it must have a variable, falling to its output the curvature of this surface. Or on the other hand, the radius of curvature of this surface or boundary energy it needs to grow continuously in the direction of the exit channel.

In this case, in the structure, at each point of the profiled surface of the channel there is a scope capture of neutrons in the corners Δφs(see Fig.3) and so this channel has the ability to capture and display in the selected direction of the neutrons on the entire width of the selectivity of the plate and in the entire volume of the selectivity patterns of the moderator.

In addition, it is important that this whole thread has a small range of angles, and it is high neutron flux density in a thin parietal layer of each selectivity plate. And therefore may be formed on lagerweij silicon wafers as ruler and square and other matrices of substances enriched with phosphorus 31 with a duty cycle between enriched strips equal to the thickness of the plates selectivity patterns.

If this is m it is necessary to pay attention to the fact, the neutron flux distribution angle of exit from the surface of a thick block of moderator is not isotropic, and has a preferential direction normal thereto and is described by the dependence off(θ)=a(cosθ+3cos2θ). Where θ is the angle of deflection of the stream of outgoing neutrons from the incident direction, θ=90°-φ. This is because due to the small run of neutrons to scattering, λssurface neutrons have time to dissipate in the nucleus before beyond the boundary of the surface unit of matter.

To reduce this effect, the distance hchbetween adjacent channels selection of neutrons and the thickness of the selectivity plate retarder hplmust be made small, much smaller than the length of the scattering of neutrons in matter λsand make units and fractions of a millimetre. As a result of such execution selectivity patterns of the distribution of neutrons in the package selectivity of thin plates of the device remains isotropic in the corners, as in a thick block of moderator, and neutrons are in the process of their movement across the multiple plates of the structure, increasing the efficiency of the process.

A possible embodiment of the device, characterized in that the selectivity of the structure is made so that the plate LEGIROVANNOGO substances placed in the channels between the fins of the retarder, and the plate can be both flat and profiled, for example, curved with variable curvature, so that the maximum radius of curvature is the center of the plate.

In this case, the irradiation of crystalline silicon occurs within a package of plates, in which the gaps between them filled by the moderator, or in the form of plates of graphite, or in the form of layers of heavy water. Plate retarder may have supersonically coating on their surface.

For a start, consider some of the radiation characteristics of the basic materials of the device in this case:

Table 2
(for thermal neutrons)Si30SiC(graphite)D2OH2O
The scattering cross section, σs(the barn)1.992.44.813.6103.0
The absorption cross section, σand(the barn)0.1710.10.0030.0010.66
Mileage to scattering, λs(cm)108.32.72.61.1
Mileage prior to the acquisition, λa(cm)11820038453·10445
The diffusion length, L (cm)2023.6541202.7
The albedo of the large block, γ0.50.620.930.970.57
The number of crossings in a thick block, k22.614332.3
The concentration at which the MOU PSM-30.05·10240.05·10240.08·10240.03·10240.03·1024
The length of slowing down to thermal energy, Ls (cm)17.711.05.4
The average angle of deviation of the neutron in the scattering, θ (deg)89°89°86°70°
(D)
48°
(H)

Thus: λs=1/nσs; λa=1/nσa;L=13λsλa;γ=1-43lL+23l;k=11-γ;cosθ =23A;Ls=λs(A2+13+118A)ln(T0T),

Where A is the atomic mass of an atom of the inhibitor, T, T0the energy of the neutron before and after deceleration. It is important that the temperature decrease in the area of selectivity patterns, and placement LEGIROVANNOGO substances increases the efficiency of the process.

It is essential that mileage to scattering of thermal neutrons in silicon is larger than in graphite or heavy water, and mileage to absorb it less than in graphite or heavy water. It is also important that the scattering of neutrons by nuclei of the moderator, on average, the deviation angle of the neutrons from the source trajectory is close to the direct corner.

In this case, the neutron, moving across the plate retarder spread on its nuclei, with virtually no absorption will take place plate retarder, but following the silicon wafer it would primarily move along its plane, to participate in the reactions enrichment of silicon phosphorus. This neutron, gently moving along the plate with the silicon in the scattering on the nuclei, will be released from the plate to the moderator again predominantly perpendicular to its plane. As a result, the efficiency of the neutron flux will increase.

In the framework of the considered packet structure field doping of silicon using the device forming the directional neutron flux and possibly around the package lagerweij plates. When the direction of the neutrons along the silicon wafers appropriate, and will increase the effectiveness of their doping.

It is essential that the device allows the doping neutrons not only silicon, but also any other substances, increasing the integral of flow in selected areas and at the same time reducing the negative impact of the background of fast neutrons.

Thus, this constructive execution of the method and device for neutron doping substances enhances the value of thermal neutron flux in selected areas LEGIROVANNOGO substances and to improve the attitude of this thread to the background of fast neutrons in them. And to improve the quality and expand the technical capabilities of electronic elements and electronic devices that are created when the application doped by neutron matter.

Brief description of drawings

Things the ity of the invention is illustrated by drawings, where:

figure 1. shows a diagram of forming a directed stream of a wedge-shaped slit;

figure 2. presents a diagram of the device for neutron doping substances, the integration of neutron fluxes case pack wedge plates;

figure 3. - elektrownie neutrons in a curved channel selection.

Device for neutron doping substance composed of anisotropic-structured device forming a directed stream of neutrons, including an external source of neutrons, slowing the substance 1, the profiled plates for selection of neutrons 2, focal area 3, the device forming a directed stream of neutrons, lagerware substance 4, the angular field of neutron capture in the selection process 5, the moving device LEGIROVANNOGO substances 6.

The implementation of a group of inventions

The implementation of the method of neutron doping substances is illustrated by the following examples.

Example 1. Lagerware substance is a homogeneous polycrystalline silicon natural composition. When irradiated by thermal neutrons is obtained the n-type semiconductor, with an increase of the integral flow F of neutrons increases the degree of doping of silicon and its conductivity. So, when an integral thread in the F=3·10171/cm2conductivity LEGIROVANNOGO the silicon will be ρ=100 Ohm·see During irradiation of silicon by means of a device for neutron doping substances in focal regions of the device, the degree of doping will be increased Ks - fold in comparison with the background, where Ks≈150. When the density of the neutron flux in the reactor 2·10121/cm2sec, the neutron flux density in the focus area selectivity plates in legroom matter will be 3·10141/cm2sec. The exposure time to achieve this conductivity will be about 18 minutes Thus, the application of the proposed method and device that allows you to increase the efficiency of doping, because it is only in the desired areas of the semiconductor.

Example 2. Lagerware substance is a homogeneous polycrystalline silicon natural composition, which upon crystallization added natural germanium composition. Depending on the concentration of germanium in the silicon source can be obtained semiconductors of different types. With increase in the composition of the atomic concentration of germanium in silicon over 0.0065 possible to obtain the doped silicon p-type. So to obtain a silicon-based radiation-doped semiconductor with the degree of compensation K=0.5 and the value of resistivity ρ=100 Ω·cm, the magnitude of the atomic concentration of germanium in silicon should be 0.00275, which is first get the integral neutron flux in 5.4·10 171/cm2. After alloying material is subjected to annealing at 800°C for 30 minutes. The application of the proposed method and device, manageable legira substance in predetermined areas of the semiconductor, can increase the efficiency of the process.

Example 3. Lagerware substance is a homogeneous single crystal of indium antimonide. Irradiation of indium antimonide thermal neutrons leads to transformation In115average of 96% natural mixture in the tin Sn116. The resulting tin atoms in the cationic sites of the lattice behave as donors. After alloying the resulting semiconductor is subjected to annealing. The application of the proposed method and device, manageable legira substance in predetermined areas of the semiconductor, can increase the efficiency of the process.

The device is considered on the example of one of the options shown in figure 2.

Fast neutrons from an external source, for example, reactor, thermalized on the substance of the retarder 1. Diffuse field of thermal neutrons, including fast neutrons that reach the device forming the directional neutron flux, placed in one of the channels. Thermal neutrons after deceleration sephirot in the corners of their distribution in the profiled plates for selection of 2 neutrons and emit their sweat is key, moving in a dedicated separating the substance structure of the retarder direction.

Depending on options, it can be neutrons moving in the direction of the widest part of the wedge-shaped channels formed between the plates 2 or neutrons that move along the curved profiled plates 2 in the direction of minimal curvature.

Due to the profiling plates 2 allows capture of neutrons on the entire surface of the wafer. Formed and directed streams of neutrons summarize in the focal region 3 legroom substance 4, resulting in the focal region increases the intensity of the neutron flux. The neutrons released from LEGIROVANNOGO matter without interacting with it, return again in the process of their separation anisotropic-structured device forming a directed stream of neutrons. And lagerware material 4 through the device move 6 LEGIROVANNOGO substance 4 is guided to move in the focal region neutron fluxes, and form a necessary integral neutron flux in its substance.

Consider several numerical examples the proposed method and device. Let selectivity of the structure is made in a variant of wedge-shaped plates with Ns=7, then the flow in the selected structure about the Asti, you can zoom in to Ks=2×(Ns-1)=12 times, taking into account the doubling from the interaction of the threads on opposite sides of the focal field of the device. Considering that it is necessary to dial the integral of flow such that the average distance between lagerweij impurities31P in the crystal was 22 nm, it is necessary that the density of the formed impurity31P in the lattice was nP=9×1016cm-1. Hence, when the density of the external thermal neutron flux in the reactor, n0=5×1013cm-2s-1time needed:t=nPKsn0σnSiintegral flow on the line will be close to 8 hours. Rulers may be, for example, a width of 5 mm at a duty cycle between them in 35 mm, and the package can include up to 80 plates 1 mm silicon installed across the beam.

In a variant selectivity patterns of plates of variable curvature, the width of the wall surface of the neutron flux hchthe output of the selectivity of the channel is less than hch≈0.1 mm, it is important that Ks does not depend on the thickness of the plates hpl≤1 mm, and the depth L of the structure. Therefore, it is possible Ks"10 and the plates LEGIROVANNOGO substances can be applied ka the rulers, and gratings substances enriched with phosphorus 31 with a width of about 0.1 mm with a duty cycle of less than 1 mm As before, the flow from the adjacent selectivity plates may be combined into a common focus and even more increased. Profile bending plates may be, for example, as part of the parabola, or part of a hyperbolic spiral, or clothoid.

If the silicon wafer is curved and placed between the plates of the moderator, the neutron flux in a thin surface layer of silicon in the vicinity of the concave part of the plate retarder, will increase as the degree of doping with phosphorus 31 therein.

1. The method of neutron doping substances, including the slowing down of fast neutrons source substance moderator, the formation of thermal neutron flux in the selected area and the irradiation by thermal neutrons LEGIROVANNOGO substances, characterized in that the fast neutron source in the process of slowing sephirot in the corners of their distribution, allocate their streams moving in the selected substance structure of the retarder direction, summarize selected structure flows, is formed in the form of narrow strips and place lagerware substance lagerware substance manageable move in the focus area neutron fluxes.

2. Device for neutron doping substances, comprising a source of neutrons, a moderator, lay the generated substance, the moving device LEGIROVANNOGO substances, characterized in that the retarder is a device of forming a directed stream of neutrons, made in the form of long anisotropic plates with structured selectivity structure with channels between them, oriented in a dedicated structure, the directions of the field focuses the flow of neutrons and lagerware substance, at least its part placed in the region of tricks neutron fluxes, and the moving device LEGIROVANNOGO substance containing the controlled actuator and control system moving into the focus area.

3. The device according to claim 2, characterized in that the selectivity of the structure of the retarder in the form of packets slab longitudinal wedge-shaped plates so that their educated wedge-shaped channel with its axis oriented in the direction of the field focuses the flow of neutrons.

4. The device according to claim 2, characterized in that the selectivity of the structure made in the form of groups of curved plates of variable curvature, such that formed between them a curved channels in areas with minimum curvature oriented in the direction of the field focuses the flow of neutrons.

5. The device according to claim 2, characterized in that the selectivity of the structure is made so that the plate LEGIROVANNOGO substances placed in the analy between the plates of the retarder, moreover, the plate can be both flat and profiled, for example, curved with variable curvature, so that the maximum radius of curvature is the center of the plate.



 

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FIELD: physics.

SUBSTANCE: invention relates to the technology of power semiconductor devices. In the method of making resistive elements of semiconductor resistors, at each ith resistive element of the batch of resistors made, before exposure, the value of change in resistance is measured. After that the batch of resistors is divided into groups with a given interval of change in resistance, and, based on a relationship between radiation dose and resistance value with change of temperature within a given range, pre-established for the given type of resistor, the value of radiation dose is assigned for resistive elements of each kth group. The resistive elements are then irradiated and annealed, and at each ith resistive element, resistance value is re-measured. If that value does not satisfy a defined relationship, irradiation is repeated, the dose of which for each ith resistive element of the kth group is determined by a defined relationship.

EFFECT: increased percentage output of resistors, with change in resistance value within a given temperature range not exceeding a given value.

2 dwg

FIELD: metallurgy.

SUBSTANCE: in the doping technique of epitaxial layers of gallium nitride by germanium, including germanium introduction into solid model, heating, annealing and cooling, germanium is introduced by means of irradiation of epitaxial layers of gallium nitride by particle flux, containing thermal neutron with flux density no more than 1012 cm-2s-1, heating is implemented with rate 10÷30 deg/min till the annealing temperature, defined by presented ratio, annealing is implemented during 20 minutes, cooling is implemented with rate 10÷20 deg/min till the temperature 450÷500°C, and then with the rate 20÷40 deg/min till indoor temperature.

EFFECT: receiving of uniformly alloyed layers of gallium nitride with improved electrophysical properties.

1 tbl

FIELD: chemistry.

SUBSTANCE: in method of processing monocrystalline epitaxial layers of group III nitrides by irradiation with fast neutrons with further heating, burning and cooling, exposed to irradiation are epitaxial layers with neutron flow density not higher than 1012 cm-2s-1, fluence F=(0.5÷5.0)·1016 cm-2; burning is carried out at 800-900°C during 20 minutes, heating is performed at rate 10-30 degrees/min, cooling to temperature 450-500°C is carried out at rate 5-10 degrees/min, and further at rate 20-40 degrees/min to room temperature.

EFFECT: improvement of electrical and physical characteristics of epitaxial layers.

2 tbl

FIELD: chemistry.

SUBSTANCE: method of making a chromatographic technetium-99m generator from neutron-irradiated molybdenum-98 involves depositing a predetermined mass of molybdenum into a chromatographic column with aluminium oxide. For this purpose, eluate output of technetium-99m from the generators with different adsorbed molybdenum mass is determined. Through extrapolation from the obtained calibration curve, the mass of molybdenum which corresponds to maximum output of technetium-99m from the generator Be=1 is found as mi=exp[(1-a)/b], where a and b are coefficients of the calibration curve Bi=a+b·ln mi, where Bi is the eluate output of technetium-99m from the generator for the adsorbed mass of molybdenum mi.

EFFECT: obtaining a generator based on neutron-irradiated molybdenum-98 with a narrow eluate profile for extracting technetium-99m.

1 cl, 3 dwg

FIELD: chemistry.

SUBSTANCE: limiting specific weight of acid mLA, required for complete termination of its reaction with aluminium oxide is determined. The amount of acid mHCl required for treating aluminium oxide with mass mox is calculated using the relationship: mHCl=mLA·mOX. After making the corresponding calculations, aluminium oxide is treated with acid, put into a chromatographic column and a molybdenum solution is added.

EFFECT: more reliable operation of a technetium-99m generator in terms of prevention molybdenum from falling into the eluate owing to achieving maximum sorption capacity of the oxide used.

3 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention concerns manufacturing of radionuclides for industry, science, nuclear medicine, especially radioimmunotherapy. Particularly it concerns method of receiving actinium -227 and thorium -228 from treated by neutrons in reactor radium-226. Method includes irradiation of target containing of metallic capsule in which there is located reaction vessel, containing radium-226 in the form of compound. Then it is implemented unsealing of target's metallic capsule, dissolving of received radium. From solution it is separated by means of precipitation, and then it is implemented regeneration, preparation to new irradiation and extraction of actinium-227 and thorium-228 from solution. At that irradiation, dissolving, radium separation, its regeneration and preparation to new irradiation are implemented in the form of its united chemical form - radium bromide, in the same reaction vessel made of platinum. Method provides reusing of the same platinum vessel for receiving of actinium-227 and thorium-228 from one portion of radium by recycling of irradiation and extraction in the same vessel. Separation of metallic capsule by means of dissolving provides saving of mechanical integrity of platinum reaction vessel for each new irradiation cycle and extraction.

EFFECT: increasing of radiationally-environmental safety of process, excluding operations of increased radiation hazard.

2 cl, 2 ex

FIELD: nuclear medicine.

SUBSTANCE: method of realizing of neutron-catch therapy is based upon introduction of medicinal preparation into damaged organ or tissue of human body. Preparation has isotope with high cross-section of absorption of neutrons. Then damaged organ or tissue is irradiated by neutrons of nuclear reactor. Irradiation is performed with ultra-cold neutrons with energy of 10-7 eV and higher, which neutrons are released from cryogenic converter of neutrons of nuclear reactor and are delivered to damaged organ or tissue along vacuum neutron-guide, which neutron-guide has end part to be made in form of flexible catheter. Dosage loads are reduced.

EFFECT: minimized traumatism of healthy tissues of patient.

4 cl, 1 dwg, 1 tbl

FIELD: production of radioactive isotopes.

SUBSTANCE: proposed method for producing nickel-63 radioactive isotope from target within reactor includes production of nickel-62 enriched nickel target, irradiation of the latter in reactor, and enrichment of irradiated product with nickel-63, nickel-64 content in nickel-62 enriched target being not over 2%; in the course of product enrichment with nickel-63 nickel-64 isotope is extracted from irradiated product.

EFFECT: enlarged scale of production.

1 cl, 2 tbl

FIELD: radio-chemistry; methods of production of the chromatographic generator of technetium-99m from the irradiated by neutrons molybdenum-98.

SUBSTANCE: the invention is pertaining to the field of the radio-chemistry, in particular, to the methods of production of technetium-99m for medicine. Determine the specific activity of the molybdenum and the sorptive capacity of the used aluminum oxide in molybdate-ions. The mass of the molybdenum necessary for production of the preset activity of the eluate of technetium-99m determine from the ratio:ATc= 0.867·L·m ln (m)/ln(mox·Wi), where:ATc - activity of the eluate of technetium-99m, Ki; L - the specific activity of molybdenum, Ki/g; m - mass of molybdenum, g;mox - the mass of aluminum oxide in the chromatograph column, g; Wi - the sorptive capacity of the used aluminum oxide in molybdate-ions, g/g. After making of corresponding calculations the solution of molybdenum is applied on the aluminum oxide. The technical result of the invention consists in production of the generator with the required activity of technetium-99m at usage of the minimum quantity of molybdenic raw.

EFFECT: the invention ensures production of the generator with the required activity of technetium-99m at usage of the minimum quantity of molybdenic raw.

1 ex, 2 tbl, 1 dwg

The invention relates to nuclear energy, in particular the production of energy, transmutation of radioactive waste, burning weapons-grade plutonium and actinides

The invention relates to radiation technique and can be used for irradiation of internal targets

The invention relates to applied radiochemistry and relates, in particular, production facilities for extraction of the radioactive isotope carbon-14, which is widely used in the form of labeled organic compounds, as well as in the sourcesradiation

The invention relates to applied radiochemistry and relates, in particular, production to obtain a radioactive isotope of carbon14With widely used as labeled organic compounds, as well as in the sourcesradiation

FIELD: metallurgy, crystal growing.

SUBSTANCE: invention refers to process of production of AIIIBV semi-conducting compositions. Mono-crystals of indium antimonide alloyed with tin are produced by means of bombardment with a full specter of reactor neutrons with successive heating, annealing and cooling. Heating is carried out at the rate of 20÷40 deg/min to temperature of annealing, defined by the formula Tanneal=450+(tgNsn-14)-7 [°C], where Nsn is concentration of introduced alloying addition of tin [cm-3]; annealing is performed during 20 minutes, while the successive cooling is carried out at the rate of 5-10 deg/min to the temperature of 350÷400°C, and further at the rate of 20-40 deg/min to an ambient temperature.

EFFECT: alloying of indium antimonide plates with tin to high concentrations, also upgraded uniformity of tin distribution and electrone mobility.

2 ex, 1 tbl

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