Method of producing thin-layer, thermally and/or optically stimulated luminescence effect based nuclear radiation charged particle detector based on aluminium oxide
SUBSTANCE: method involves evaporating a target of starting material with a pulsed electron beam with energy of not more than 100 keV, pulse duration of 20-300 mcs, energy density of not less than 1 MJ/cm2; a beam of electrons on the path to the target is passed through a system of generating a gas pressure drop, through which pressure of 1-20 Pa is provided in the evaporation chamber in order to cool particles, wherein particles are deposited on cooled substrates made of metal whose melting point is higher than 900°C, and the coefficient of linear thermal expansion is close to that of the deposited layer of aluminium oxide, the thickness of which is controlled in the range of 5-40 mcm by deposition time of 5-20 minutes, and radiation sensitivity is controlled by final heat treatment in the range of 550-900°C for 10-20 minutes.
EFFECT: high accuracy and reliability of detecting doses of short-range charged particles of nuclear radiations, including complex fields using TL or OSL techniques.
The invention relates to methods for thin detectors of charged particles, based on thermally induced phenomena and/or optically stimulated luminescence. As a sensitive substance thin detectors proposed alumina. The invention can be used to improve the reliability, accuracy and reliability of measurements of doses of heavy charged particles, nuclear beta-, alpha - and positron emitters methods luminescent solid state dosimetry.
Currently, domestic and foreign practice is widespread developed in Russia thermoluminescent detectors on the basis of anion-defective single crystal α-Al2O3marked TLD-500K, TLD-500 or α-Al2O3:In the foreign literature (TU 2655-006-02069208-95; monitoring external occupational exposure. General requirements. HOWTO MU 188.8.131.52-2000. Moscow, 2000, p.50; Dosimeter Materials, Harshow TLD Model 8800, Bicron Ne, brochure). In recent years, this same material is used extensively as a detector of ionizing radiation, the luminescence of which is proportional to the accumulated dose excited (stimulated) is not heated, as in thermoluminescent dosimetry, and the illumination light (Boons, R. et al. External and Environmental Radiation Dosimetry with Optically Stimulated Lumiescent Detection Device Developed at the SCK-CEN. World Journal of Nuclear Science and Technology, 2012, 2, 6-15).
Physical and instrumental aspects of solid state dosimetry, based on the phenomena of optically and thermally stimulated luminescence (OSL and TL), thrive in leading dosimetry laboratories of the world (L. Botter-Jensen et.al. Optically Stimulated Luminescence Dosimetry. Elsevier Science B.V. 355 - P, (2003); S.W.S. McKeever. Optically stimulated luminescence: A brief overview. Radiation Measurements 46 (2011)1336-1341; US PATENT #6,936,830, Gaza, R. et al. Optically stimulated luminescence radiation dosimetry method to determine dose rates during radiotherapy procedures. (August 30, 2005); US PATENT #7,141,804, Akselrod, M.S. et al. Detection of neutrons and heavy charged particles. (November 28, 2006); Sawakuchi, G.O. et al. Relative optically stimulated luminescence and thermoluminescence efficiencies of Al2O3:C dosimeters to heavy charged particles with energies relevant to space and radiotherapy dosimetry. J.Appl. Phys. 104(2008) 124903; N.J.M. Le Masson. Development of Optically Stimulated Luminescent Materials for Personal Fast Neutron Dosimetry. Delft University Press. 168-P, (2003); T. Hashimoto, T. Nakagawa, D-G. Hong. Et al. An Automated System for Red/Blue Thermoluminescence and Optically Stimulated Luminescence Measurement. Journ. of Nuclear Science and Tecnology, Vol.39, No 1. pp.108-109 (2002); RF Patent №2399928 I.I. Milman and other Method of excitation radiation signal optically stimulated luminescence detectors of ionizing radiation on the basis of aluminum oxide (2010. 09 20); RF Patent №2310889 I.I. Milman and other Device for measuring dosimetric signal optically stimulated luminescence (2007.11.20)).
TL-OSL detectors on the basis of anion-defective single crystal α-Al2O3designed for registering the x-ray and gamma-radiation. They have a cylindrical shape with a height of 1 mm and a diameter of 5 mm cumulative dose in them is determined by the luminescence of the total volume of the detector, and therefore they are not effective for determining the doses of corpuscular radiation with large linear energy loss (let), which runs in the detector material amount to several tens of micrometers. So it is estimated mileage of beta particles with an energy of 90 Kev in α-Al2O3at normal incidence is equal to 38 microns, with an energy of 250 Kev to 200 microns, with an energy of 800 Kev - 1 mm In the fall of particles on the surface of the detector at an angle of their ranges become smaller. For thin detector, in contrast to bulk, you should expect smaller energy dependence of the sensitivity of the detector. Thus, it becomes obvious that for the registration of corpuscular radiation with high linear energy transfer (let especially in mixed, for example beta-gamma fields, for separating the contributions of doses created by different types of radiation, it is necessary to use detectors with thin sensitive layers. For tissue-equivalent depth of penetration of the beta particles is recommended by international standards the thickness of the sensitive layer of the detector should be 20 μm, that is, to have mass thickness equal to 7 mg/cm2. It should be noted that the mass thickness is, often used in dosimetry and measured in mg/cm2, is defined as the product of the thickness of the absorber density. To solve complex problems related to registration of charged particles on the background of photon-ionizing radiation, the creation of a thin layer of detectors, the thickness of which should be substantially less than the length of the run of particles in them. Moreover, for example for skin dosimetry, according to the requirements of norms of radiation safety NRB-99/2009 thin detectors should be in thickness equivalent to the thickness of the basal layer of the skin 5 mg/cm2(~12 µm for corundum when ρ=3920 mg/cm3)under the epidermis to a depth of 5 mg/cm2. As can be seen from the above, the required thickness of the detector must be small and it is extremely difficult to achieve the refinement of known thermoluminescent detectors, such as the best of them TLD-500K, based on the single crystal anion-defective corundum.
Problem skin (skin) dosimetry become increasingly important with the expansion of applications of nuclear medicine uses beta and positron-emitting radiopharmaceuticals for the diagnosis and treatment of cancer. Table 1 shows the power characteristics of some common nuclear medicine radionuclides.
|Energy characteristics of β-emitting radionuclides|
|Radionuclide||Types of radiation|
|Ecf, Kev||Emax, Kev||Output %||Ecf, Kev||Output %|
The data of table 1 show the necessity of creating a thin layer of detectors for detecting low-energy beta radiation, including in mixed beta-photon fields. When such detectors for use in t - and/or OSL dosimetry is natural to use one of the most sensitive materials on the basis of anion-defective corundum.
From the literature there are ways to create a thin layer TL/OSL detectors beta radiation on the basis of α-Al2O3:Taken analogues decisions in the present invention.
In the method described in M.S. Akselrod et al. A thin layer of AL2O3:C TL beta detector. Radiation Protection Dosimetry. Vol.66, Nos.1-4, pp.105-110 (1996),three-dimensional monocrystalline detector Al 2O3:With mechanical razmalyvanija to powder in an iron mill. Time grinding ranged from 2 to 6 hours. The powder was treated with hydrochloric acid to remove iron impurities were washed with water and dried with hot air. The described method allowed us to obtain a powder with a grain size from 1 to 160 μm. The TL sensitivity of the detector in the form of powder depended on grain size and substantially reduced when the grain sizes were less than 40 microns. The next stage in the development of this technology was the consolidation of the powder on the substrate, made of different materials, including heat-resistant polymer film and metal foil. The best results (linearity of dose dependences of 10-515 G and a minimal dependence of the output t from the energy beta particles (147Pm,204Tl,90Sr/90Y), 1.5 times have been achieved for powdered detector on the basis of α-Al2O3:C with a grain size of 20-40 μm, deposited on aluminum substrate thickness of 0.2 mm and held it forces the adhesive bond. Considered in the example method laid the basis for industrial production on the basis of α-Al2O3:With a thin layer TL-OSL detectors firm Landauer, Inc. (USA), currently used (T.N.O. Pinto et al. Measuring TL and OSL of Beta Radioisotops inside a Glove Box at a Radiopharmacy Laboratory. Radiation Measurements, v.46, N12 (2011)1847-1850). Describes the initial method of obtaining a thin layer of α-Al 2O3:Detectors is characterized by high complexity and material costs associated with obtaining the volume of the material, its mechanical refinement and consolidation of the obtained powder on a metal substrate for the registration of TL and OSL or between the optically transparent organic films to measure only the GSP. In addition, obtained by the above-described technology detectors have considerable thickness of the active layer (~130 µm), which does not allow correctly (according to the standards NRB-99-2009) to assess the dose from beta radiation in the basal skin layer thickness of 5 mg/cm2under the surface layer thickness of 5 mg/cm2.
In the method described in the work of M.W. Blair et al. Nanophosphor aluminum oxide: Luminescence response of a potential dosimetric material. J.of Luminescence 130(2010) 825-831, to create a thin layer of the detector was used nano α-Al2O3. Industrial nano-Al(OH)3(18 g) were dissolved in nitric acid (40 ml, HNO3, 65 wt%). After the exothermic reaction has stopped, the liquid was added a certain amount of fuel catalyst (glycine, urea and hexamethylenetetramine). Before final heat treatment the mixture was dried in a vacuum oven at 115°C for 18 hours. Heat treatment was carried out in air in a muffle furnace at 620°Stopanimating annealing in air at 1000°C is for 1 hour was made to get rid of residues of catalyst, nitrate and for the formation of stable a - phase Al2O3. Powder with a grain size of 2 nm was recorded on a steel backing with a silicone adhesive and irradiated by the radiation source90Sr/90Y dose 0,gr/s and 0,gr/s TL and OSL was measured by a standard method. The results were compared with volumetric detectors based on α-Al2O3:C. the decay Curves of FRA in time and Glov-t curves of thin detectors synthesized using different catalysts had similar views. However, he was quite different from the similar for volumetric detectors based on α-Al2O3:C. the Parameters TL and OSL at the detectors, the active part of which was made on nanotechnology, greatly depended on the type of catalyst modes of heat treatments. Moreover, when normalized responses compared detectors on their mass sensitivity of volumetric detector was more than two orders of magnitude higher sensitivity best obtained by nanotechnology. Similar results described above were obtained by the use of different types of technology for nanoscale particles of α-Al2O3to create a thin film detector (V.S. Kortov et al. Luminescence properties of nanostructured alumina ceramic. Radiation Measurements 43(2008) 341-344). The disadvantages of the described methods of obtaining thin detective is a ditch on the basis of α-Al 2O3is a complex chemical production technology. TL and OSL properties of the detector material are difficult-to-reproduce because of their dependence on many parameters of the receive mode, the type and purity of the reagents. In addition, in the above methods divided the stages of obtaining sensitive substance detector and its mounting on a metal substrate.
In ways that are close to being described in the works of S. Green et al. Optical properties of nanoporous peremestivsheesya obtained by aluminium anodization. Phys. Stat. Sol. (c) 4, No.2, 618-621(2007) and H. Efeoglu et al. Anodisation of aluminium thin films on p++Si and annihilation of strong luminescence from Al2O3. J. of luminescence 130(2010)157-162, thin films of aluminum oxide obtained by electrochemical anodization of aluminum foils. The developed technology consists of two stages. At first, high purity (>99.5%pure) aluminum foil, previously subjected to ultrasonic cleaning and mechanical and electro-polished, etched in peremestivsheesya oxalic acid. The duration of the anodization of the first stage is at least 2 hours. During this time, the film thickness reaches values of about 8 μm. The second stage of anodizing dlyatsa 6 to 8 hours. The ionization potential at both stages was maintained equal to 40 C. the Anodizing was carried out at constant temperature T1=20°C and T2=2°C with the average density is the capacity of current i 1=8,0 mA/cm2and i2=1,9 mA/cm2. The thickness of the films obtained in these modes, was d1=90 μm and d2=29 μm, respectively. Luminescent properties of the films were well expressed and correlated with known for three-dimensional dosimetric crystals of Al2O3:C, in both cases, responsible for the luminescence was centers F-type. The disadvantages of the method of obtaining thin optically active Al2O3coatings is the duration and the complexity of the process, the strong dependence of the resulting luminescent properties (intensity and spectrum of luminescence from the temperature holding anodizing.
From the above examples that the known methods for producing thin-film detector of charged particles on the basis of aluminum oxide include several technological stages and have a long duration in time. They require a high quality of raw materials. Luminescent properties of materials resulting from the application of the methods adopted for the analogs of the present invention have low sensitivity and irreproducibility. These circumstances do not allow to improve the reliability, accuracy and reliability of the registration of heavy charged particles, nuclear beta-, alpha - and positron izlucheniya t - and/or donkey-m is togami solid state dosimetry.
The closest in technical essence and the achieved result of the present invention should be considered as a method of obtaining nanopowders and device for its implementation, protected by the RF patent №2353573 published 27.04.2009. The authors are Y.A Cats, HE the Sokovnin, VG Ilves, Chang Ku Ri. The referenced patent is selected as a prototype.
This method involves evaporation of the target by the electron beam, the condensation of the vapors of the material in the evaporation chamber and the deposition of nanopowder. Evaporation of the target provide a pulsed electron beam with an energy of not more than 100 Kev, pulse duration of from 20 to 300 μs, an energy density of at least 1 MJ/cm2. The electron beam is conducted through a system of creating a differential pressure gas, whereby the evaporation chamber to create a gas pressure in the range of 1-20 PA for cooling particles, the deposition of which are manufactured on a cooled rotating disk.
Justification of the choice of method of obtaining nanopowders, taken as a prototype, is that it is based on the melting of the source material in the reducing environment of the vacuum. As our investigations have shown in this case in the anionic sublattice crystals α-Al2O3creates a lack of oxygen, based on which is formed a high concentration of active luminescent F - and F+-centers. And the Enen this technology is the basis for the creation of thermoluminescent detectors TLD-500K (α-Al 2O3:) Sensitive material which was later widely used in OSL dosimetry (A.S. No. 993728. The method of thermal processing of matter solid-state detector of ionizing radiation on the basis of aluminum oxide. Contributors: Axelrod, MS, A.F. Zatsepin, Courts B.C., Milman I.I. Registered in the State. register of Fig. 01.10.1982; A.S. No. 1347729. The method of processing substances solid-state detector of ionizing radiation on the basis of aluminum oxide. Authors: B.C. Courts, Milman I.I., Surdo A.I., Axelrod, MS, Afonin HUD Registered in the State. register of Fig. 22.06.1987). Thus, there is reason to expect high sensitivity substance thin film detector obtained by the method adopted for the prototype, using as a starting material powder of α-Al2O3. In addition, in the known method (prototype) in contrast to the significantly reduced time to obtain the final product.
However, in the known method, taken as a prototype, ignores the fact that the material powders of Al2O3regardless of the production method, is a multiphase system, while most fluorescent activity has a crystalline α-phase of Al2O3. To create a dominant α-phase of Al2O3to get the connection and, therefore, is stijene maximum sensitivity of the thin-film material of the detector is necessary to heat treatment at high enough temperatures, up to 900°C and above, not provided for in the method adopted for the prototype. In addition to changes in the phase composition of the material of the detector, heat treatment required to convert complex inactive centers F2type arising from rapid cooling of the vapor of the source material on a cooled substrate, in a simple active F - and F+centers.
In the method adopted for the prototype, there are no special requirements for material to be cooled disk on the surface which produces the precipitation of the nanopowder. Moreover, the output nanopowder becomes greater than less strongly sprayed material associated with the material of the rotating disk.
On the contrary, for thin-layer detector, which is the end product and representing deposited on a substrate sensitive layer, the substrate material is of fundamental importance. Such material should have a coefficient of linear thermal expansion close to the coefficient of linear thermal expansion of the deposited sensitive layer of aluminum oxide to provide a mechanically stable and heat-resistant connection, and should have good thermal conductivity. The heat resistance of the substrate follows from the necessity of heating the detector to 900°C for 15 minutes to empty the deep traps, as is the case for detectors TLD-500K OS is ove bulk compounds α-Al 2O3(THE 2655-006-02069208-95). Thus, the known method does not allow to obtain in a single technological cycle finished product thin - film detector of charged particles nuclear radiation on the basis of aluminum oxide.
The method selected for the prototype, it is not possible to solve in the invention of the task, you have to create a thin layer detector of charged particles on the basis of aluminum oxide, based on the effects of thermally and/or optically stimulated luminescence and, especially, to improve the reliability, accuracy and reliability of measurements of radiation doses of the above methods luminescent solid state dosimetry.
The solution of a technical problem is achieved by the fact that the source material in the form of a powder of aluminum oxide is evaporated pulsed electron beam with an energy of not more than 100 Kev, pulse duration of from 20 to 300 μs, an energy density of at least 1 MJ/cm2the electron beam towards the target is carried out through a system of differential gas pressure, which in the evaporation chamber to provide a pressure in the range of 1-20 PA for cooling of the particles, and the product of condensation of vapors of the material precipitated on the cooled substrate, which is the basis of the detector. To ensure the adhesion strength of the film with the substrate when the temperature of the finish termopan the weave they are made from materials, the melting temperature exceeding 900°C, and the coefficient of linear thermal expansion close to the coefficient of linear thermal expansion of the deposited layer, the thickness of which is from 5 to 40 μm regulate the deposition time from 5 to 20 minutes, and sensitivity to radiation - finishing heat treatment in the range of 550-900°C for 10-20 minutes.
The lower limit of the thickness of 5 μm due to the smallness of the volume of the sensitive layer and its failure to effectively transfer energy charged particles and, as a consequence, the low sensitivity of the proposed thin-layer detector. The thickness equal to 40 μm and the corresponding upper specified limit, meets the requirements of the largest run of the charged particles in the sensitive layer, however, with the growth of its mass increases the probability of interaction of photon-ionizing radiation, which complicates the separation of their contributions to the total dose.
Thus, the proposed invention, the optimum thickness range at the same time meets the requirements of radiation safety NRB-99/2009, according to which the thin-film detectors should be in thickness equivalent to the thickness of the skin 5 mg/cm2(~12 µm for corundum).
The above range of thickness of 5-40 μm was achieved by the appropriate time on the ardenia 5-20 minutes. The output of a specified time interval leads to the formation of the sensitive layer is not optimal thickness.
The necessity of finishing heat treatment in the range of 550-900°C for 10-20 minutes driven by the requirements of the devastation of the deep traps, strongly influencing the sensitivity of the detectors, stabilization defective anionic structure of the sensitive layer and to increase its mechanical strength.
The results of experimental verification of the proposed method of obtaining thin-layer detector of charged particles nuclear radiation on the basis of aluminum oxide are summarized and illustrated below the images.
Figure 1 shows the effect of finishing heat treatment and the type of substrate material on the intensity of the TL samples of thin detectors with thickness of the active layer 20 μm, obtained during the deposition, is 5 minutes. As the substrate material was chosen foil from aluminum (curve 1), copper (curve 2), iron (steel) (curve 3), tantalum (curve 4) and graphite (curve 5). The finish heat treatment was carried out after deposition of the film. After the samples were irradiated low-energy x-ray radiation (40 kV, 40 mA, Rh-anode) and measured TL or OSL according to standard methods. Choice of soft x-rays as low-path simulator beta particles for testing lumines entei activity of the obtained thin-film detectors due to its almost complete absorption in the active layer of the detector, by reducing the time of choosing the optimal technology and experimental verification of the proposed method.
Data in figure 1 demonstrate the high TL sensitivity of the resulting detectors, its dependence on the type of substrate material and temperature of the final heat treatment.
Substrate, the melting temperature of which does not exceed 700°C (aluminum, copper), does not allow to produce high-temperature finish annealing. Films on graphite substrates were destroyed at 800°C due to significant differences in the coefficients of linear thermal expansion of corundum (α=8,5·10-6°C-1) and graphite (α=54,4·10-6°C-1). A substrate of tantalum have a coefficient of linear thermal expansion close to that of corundum α=5,3·10-6°C-1but the intensity of the TL when it is lower than detectors with a substrate of iron. As can be seen from figure 1 the optimal material for the substrate of the thin-film detector is iron, its coefficient of linear thermal expansion α=11·10-6°C-1not much different from the coefficient of linear thermal expansion of the sensitive substance detector. The material of such a substrate allows the finish heat treated to 1100°C to increase the sensitivity after the deposition of the film and up to 900°C during operation of the detector.
The data of figure 1 were used as the basis for the selection of substrate material and modes of finishing heat treatment of thin-layer detectors in the alleged invention. Temperature range of finishing heat treatment of thin detectors with the substrate, made of iron, selected in the range 550-800°C, time - within 10-20 minutes. In this case, as follows from figure 1, changes in the intensity of t does not exceed 10%.
Figure 2 shows the curves of termomassazhnye sample thin-film detector with thickness of the active part 20 μm, deposited on a steel substrate, depending on the dose of beta radiation source90Sr/90Y in the range 20-4400 mGy (curves 1-6). Data 2 is used to construct the dose dependence of the yield of t, shown in figure 3. From figure 3 is shown the linearity of the output of t, also called sitesmay, in the range of doses 20-4400 mGy, satisfying the requirements of the skin dosimetry (NRB-99-2009, J.S. Durham et al. Design of a finger ring extremity dosemeter based on OSL readout of α-Al2O3:C. Radiation Protection Dosimetry, 2002, Vol.101, Nos. 1-4, pp.65-68). These requirements establish the annual limit of 500 mg.
The choice of thickness of the active layer of the detector was based on the dependence of the luminescence output from the thickness of the active layer when irradiated by the radiation source90Sr/90Y (T.N.O. Pinto, L.V.E. Caldas. Determination of transmission factors for beta radiation using Al2O3:C commercial OSL dosimeters. Nuclear Instruments and Methods in Physics Research A 619 (2010) 353-355). Analysis of the results of our research and the literature showed that the thickness of the active layer of thin-layer detector in the range of 5-40 microns to ensure the registration of beta radiation with average energies from 60 to CAV methods TL and OSL. The influence of thickness of the active layer of the detector on the output of t is illustrated in figure 4. It is seen that with increasing the coating thickness of 20 μm →32 μm →40 μm output t increases. Further increase in thickness resulted in saturation of the output of the TL. Similar patterns were observed when measuring OSL detectors with thicknesses of the coatings 20, 32 and 40 µm (figure 5). Data figure 4 and figure 5, the available literature was the basis for the range of thicknesses of the active layer of thin-layer detectors of charged particles nuclear radiation on the basis of aluminum oxide, equal 5-40 μm. In accordance with the selected in the present invention method, the time to reach the thickness of the active layer detectors 5-40 μm is 5 to 10 minutes.
For testing in real conditions was used exemplary alpha source239Pu with particle energy 5,15, 5,13 and 5.1 MeV. The yield of alpha particles is accompanied by gamma radiation, substantially unable to initiate a thin layer of the detector, while alpha particles lose all their energy in the sensitive layer. Figure 6 shows the curves of termomassazhnye samples of thin-layer detectors, obtained by the proposed method and irradiated mixed alpha gamma radiation source239Pu directly (curve 1), through the paper with a density of 80 mg/cm2(curve 2) and the substrate (curve 3). From this example, visible high e is the efficiency of registration of alpha radiation on the background of the accompanying gamma radiation, a minor contribution of which to the total accumulated setosum (curve 1) can be estimated from curves 2 and 3.
An additional advantage of the invention is that, as shown by our measurements, for the registration of electrons in mixed beta-gamma field, such as90Sr/90Y-source, obtained by thin-layer detectors allow us to determine the contribution of only the beta component of the absorbed dose. The results of experimental verification of this possibility using thin-layer detectors, obtained by the proposed in the invention method, is shown in Fig.7. Curve 1 corresponds to t thin-layer detector irradiated from the side of the active layer mixed gamma-beta radiation source90Sr/90Y. In another case (curve 2) to highlight the gamma component of the mixed radiation between the source and the detector was placed aluminum filter thickness of 1 mm can be Seen (curve 2)that the contribution of photon-ionizing radiation source90Sr/90Y in accumulated sutasoma the proposed detector is negligible. However, to accurately determine the dose from beta-component of the mixed radiation specified contribution can be taken into account by subtracting ([curve 1] - [curve (2)]), even if it is significant.
A method of obtaining a thin layer based on the effects of thermally and/or pricheski stimulated luminescence detector of charged particles nuclear radiation on the basis of aluminum oxide, includes evaporation of the target source material pulse electron beam with an energy of not more than 100 Kev, pulse duration of from 20 to 300 μs, an energy density of at least 1 MJ/cm2the electron beam towards the target is carried out through a system of differential gas pressure, which in the evaporation chamber to provide a pressure in the range of 1-20 PA for cooling particles, characterized in that the deposition of particles to produce a cooled substrate made of metal, the melting temperature exceeding 900°C, and the coefficient of linear thermal expansion close to the coefficient of linear thermal expansion of the deposited layer of aluminum oxide, the thickness of which is from 5 to 40 μm regulate the deposition time from 5 to 20 min, and the sensitivity to radiation - finishing heat treatment in the range of 550-900°C for 10-20 minutes
SUBSTANCE: masking coating, and namely perfluoropolyether is applied onto a substrate. Then, a copper layer or an aluminium layer with surface resistance of about 90-110 Ohm/m2 is applied by means of a selective vacuum metallisation method; after that, a current-carrying layer of silver-containing paint with silver content in the amount of 70-90% is applied by means of a screen printing method. Surface resistance of the obtained current-carrying coating is measured by means of a four-probe control method. Sections of the substrate are rejected, which do not correspond to the required technical characteristics determined from the condition of allowable spread of surface resistance of not more than 15% in absolute units.
EFFECT: improving producibility; enlarging operating capabilities; reducing production costs; improving measurement accuracy.
2 cl, 1 tbl
SUBSTANCE: invention relates to the field of nanotechnology and can be used for production of atomic-thin single-crystalline films of various multilayer materials. In the method of production of atomic-thin single-crystalline films, comprising the selection of thin single-crystalline fragments of starting layered single crystals, gluing them to the working substrate is carried out using epoxy adhesive, and the consequent removal of layers from thin single-crystalline fragments using, for example, adhesive tape.
EFFECT: simplification of the manufacturing technology of atomic-thin single-crystalline films.
11 cl, 4 dwg
SUBSTANCE: semiconductor or dielectric condensed medium is exposed to an electromagnetic pulse to generate a circularly or elliptically polarised electromagnetic wave, characterised by that circular polarisation frequency of the electrical component of the field is superposed with the electrostriction frequency of a sound standing wave formed on the surface of a cluster of substance, which generates circular current breakdown on the surface of the cluster, which leads to change in properties of the semiconductor and dielectric condensed substances which relax over time after the electromagnetic exposure stops (echo-signal).
EFFECT: controlling variable parameters of a substance.
2 cl, 13 dwg
SUBSTANCE: in the method of assembling microelectronic components, once a position fixing polymer (4), in order to maintain alignment of microelectronic components (2) that are assembled on a substrate (1) using an anisotropic electroconductive film (7), is applied onto the substrate and hardened, the microelectronic components (2) are heated to a predetermined temperature and compressed at a predetermined pressure using a flexible sheet (5) provided on the microelectronic components and then subjected to single-step compressive fixation on the substrate (1).
EFFECT: providing a method of assembling microelectronic components which, when using an anisotropic electroconductive film to assemble a plurality of microelectronic components of different height on a base plate, allows assembling at precise positions on the base plate, thereby preventing position shift which results from compressive fixation.
5 cl, 16 dwg
FIELD: electrical engineering.
SUBSTANCE: invention is related to the method for manufacturing of wafer holder for electrostatic wafer chuck with acceptable efficiency, free from unsatisfactory removal of semiconductor wafer which is a substrate and is to be treated from the first moment of electrostatic chuck delivery for new usage. The method of electrostatic chuck manufacturing is aimed to coat surface of the holder body having electrodes. It includes stages of sintered body receipt by raw power formation by pressing into a mould and its further sintering, formation, polishing of the sintered body surface, which will contact with substrate; it should be treated up to certain degree of roughness and smoothness; and then performance of spot blasting in order to remove only separable particles which appear in result of the above polishing.
EFFECT: wafer improvement.
2 cl, 2 dwg
FIELD: electrical engineering.
SUBSTANCE: cassette for group transportation of semiconductor plates contains four fluoroplastic rods with slots and two fixtures at the rods butt-ends; each of the four rods represents a fluoroplastic tube with a dense rubber insert along the whole of the tube length; the tube wall thickness is equal to (30-40)% of the slots depth that is identical for all the slots; the two side rods are positioned on the sides of the semiconductor plates as may be placed inside the cassette; one lower rod, playing the role of the cassette bottom, is positioned below the semiconductor plates as may be placed inside the cassette; the cross-section of the slots in the side rods is "П"-shaped; the side rods width exceeds the plate thickness by 50-70%, the side slots depth exceeds their width 2-4.5 times; the cross-section slots in the lower rod for plates placement is shaped as a semicircle with a radius amounting to 0.6-0.8 of the plate thickness; the fourth rod also has slots, their shape representing mirror reflection of that of the slots made in the lower rod to ensure plates fixation in the course of transportation; the slots in the fluoroplastic tube and the rubber insert of each rod are made simultaneously in the course of a single cutting operation.
EFFECT: exclusion of plates losses during transportation operations, simultaneous acceleration and handling freedom enhancement.
FIELD: electrical engineering.
SUBSTANCE: cassette for group transportation of semiconductor plates contains four fluoroplastic rods with slots and two fixtures at the rods butt-ends; each of the four rods represents a fluoroplastic tube with a dense rubber insert along the whole of the tube length. The tube wall thickness is equal to (30-40)% of the slots depth the is identical for all the slots; the two side rods are positioned on the sides of the semiconductor plates as may be placed inside the cassette. One lower rod, playing the role of the cassette bottom, is positioned below the semiconductor plates as may be placed inside the cassette. The cross-section of the slots in the side rods is "П"-shaped. The side rods width exceeds the plate thickness by 30-50%. The cross-section of the slots in the lower rod is shaped as an upturned equilateral trapezium so that the trapezium upper (major) base is less than the semiconductor plate thickness by (100-120)% while the trapezium lower (minor) base exceeds the plate thickness by (30-50)%. The fourth rod also has slots, their shape representing mirror reflection of that of the slots made in the lower rod. The slots in the fluoroplastic tube and the rubber insert of each rod are made simultaneously in the course of a single cutting operation.
EFFECT: invention enables exclusion of plates losses during transportation operations due to exclusion of plates sticking in the slots with simultaneous acceleration of movements as may be carried out and handling freedom enhancement.
SUBSTANCE: cassette has a three-wall housing with longitudinal reinforcement ribs and guide ridges on side walls on the outer and inner surfaces, respectively, and satellite holders. The latter are in form of a pair swivelling supports with a common horizontal axis. The supports are placed in windows on each of the side walls symmetrically about the longitudinal and transverse axes. Horizontal axes of the holders are mounted on the outer side of the walls on supports in form of sliding pieces, which are configured to move on the longitudinal reinforcement ribs with a "fish tail" profile. The windows are such that the ends of supports can be fitted into their openings, with vertical movement of axes and swivelling of the holder supports. The cassette can be provided with stacking elements in form of ridges on the outermost reinforcement ribs.
EFFECT: high reliability of loading and withdrawing satellites, fewer defective articles by preventing damage to photoconverters, reduced weight of the housing owing to smaller thickness of the side walls.
4 cl, 4 dwg
SUBSTANCE: in the method to manufacture multi-level thin-film microcircuit chips, including alternate vacuum application of conductor layers onto a substrate with subsequent development of a pattern of a chip by the method of photolithography, application of insulating layers and formation of level-to-level connections in them from one conductor layer to another by etching transition windows in the insulation and their dusting with a conducting material, level-to-level connections are formed by dusting of transition windows simultaneously by sputtering of the conductor layer of the appropriate level and making a pattern of the chip by the method of photolithography, besides, level-to-level connections are formed of a larger size than the size of transition windows in plan. In each subsequent insulating layer they etch transition windows of a larger size compared to the previous one.
EFFECT: simplified technology to make microcircuit chips and their higher reliability.
2 cl, 2 dwg
SUBSTANCE: solid-state material is taken, which has a thermal expansion ratio and at least one surface suitable for generation of a layer on it. A polymer layer is formed on the specified surface so that adhesion remains between a solid-state layer and a polymer layer within the entire specified range of TS temperatures between the first temperature and the second temperature. The polymer layer has a thermal expansion ratio different from the thermal expansion ratio of the solid-state material. Further the solid-state material and the polymer layer attached by adhesion are exposed to variation of local temperature from the first temperature, which is not higher than approximately 300°C, to the second temperature, which is lower than approximately room temperature, thus causing mechanical stress in the solid-state material due to difference between the thermal expansion ratio of the solid-state material and the thermal expansion ratio of the polymer layer, in order to cause breakage of the solid-state material along the inner plane in the thickness of the solid-state material, to manufacture at least one autonomous solid-state layer from the specified solid-state material. The polymer layer is additionally characterised by vitrification temperature, which is lower than approximately the first temperature and higher than approximately the second temperature, and is sufficiently low to prevent breakage or cracking of the polymer at the second temperature.
EFFECT: development of the method of thermal treatment to manufacture high-quality autonomous solid-state layers preserving characteristics of an initial material, of which they are made, and used for microelectronics.
20 cl, 6 dwg, 1 ex
SUBSTANCE: method involves obtaining a biocompatible coating on dental implants made of titanium and alloys thereof, which involves placing articles into an aqueous electrolyte solution containing potassium hydroxide and nanostructured hydroxyapatite in form of an aqueous colloidal solution, and exciting micro-arc discharges on the surface of the articles. The treated articles are oxidised in a chemical-resistant non-conducting bath: two batches of treated articles are simultaneously placed in the electrolyte solution by pre-attaching articles of one batch to terminals for treated articles, and articles of the other batch to terminals of an auxiliary electrode; and the electrolyte further contains sodium hydroxide, sodium hydrophosphate, liquid sodium glass, sodium metasilicate, in the following ratios, with respect to mass of dry substance in g/l of the composition: potassium hydroxide KOH - 2, sodium hydroxide NaOH - 1, sodium hydrophosphate Na2HPO4×12H2O - 5, liquid glass nNa2O·mSiO2 (M=3.2) - 5, sodium metasilicate Na2SiO3×9H2O - 8, nano-dispersed hydroxyapatite - 0.5-5. Deviation from said concentrations of electrolyte components does not exceed ±10%.
EFFECT: improved method.
1 tbl, 4 dwg, 1 ex
SUBSTANCE: composition for making sensor coatings contains antimony-doped tin dioxide of the formula SbxSn1-xO2, where x=0.1-0.3, and water in ratio SbxSn1-xO2:H2O = 89-87:11-13 wt %. The method of preparing the composition involves hydrothermal treatment of tin and antimony hydroxides at 170°C for 48 hours. The tin and antimony hydroxides are obtained by dissolving Sn and Sb metal in concentrated hydrochloric acid, 18-20 wt %, while adding 3-5 wt % concentrated HNO3. The obtained solution is 2-3 times diluted with distilled water and a calculated amount of ammonia solution is added. Using a simple scheme, the disclosed method enables to obtain nanoparticles of said composition SbxSn1-xO2 with size of 30 nm and surface area of 154 m2/g, which can be used as the basic component of electroconductive ink for printing sensor arrays and microcontacts.
EFFECT: low labour and power consumption.
3 cl, 6 dwg, 3 ex
SUBSTANCE: invention can be used in magnetic nanoelectronics for magnetic registering media with high recording density, for magnetic sensors, radio-absorbing screens, as well as in medicine. Method of obtaining magnetite nanoparticles, stabilised with polyvinyl alcohol, includes obtaining magnetite in alkali medium of mixture of salts of bi- and trivalent iron and polyvinyl alcohol with weight content in initial mixture from 4 to 18 wt %, dispersion, washing and carrying out all operations under continuous ultrasound impact. Process of sedimentation of salts of bi- and trivalent iron and polyvinyl alcohol is carried out in ammonia vapour, with application of aqueous ammonia (NH4OH) or hydrazine hydrate (N2H4·H2O).
EFFECT: invention makes it possible to reduce scatter of magnetite nanoparticles by size, reduce labour consumption and expenditures in the course of process.
2 dwg, 2 ex
SUBSTANCE: invention relates to field of catalysis. Described is catalyst for recycling heavy oil fractions, in which active component, selected from nickel, or cobalt, or molybdenum, or tungsten compounds, or any their combination, is applied on inorganic porous carrier, consisting of aluminium oxide, dioxides of silicon, titanium or zirconium, alumosilicates or iron silicates, or any their combination, characterised by the fact that said catalyst contains macrospores, which form regular spatial macropore structure, and portion of macropores with size more than 50 nm constitutes not less than 30% in total specific volume of said catalyst pores.
EFFECT: increase of catalyst activity.
4 cl, 3 dwg, 1 tbl, 7 ex
SUBSTANCE: invention refers to medicine, namely to experimental studies in oncology and may be used for assessing the anti-tumour action of metal nanoparticles (NP). An iron nanoparticle suspension 1.25 mg/kg is introduced into grafted Pliss lymphosarcoma intratumourally. That is followed by the paratumoural introduction of methotrexate 0.2 mg/kg. The tumour is locally heated to temperature 42-43°C using an electromagnetic UHF emission at frequency 12.7 MHz for 10 minutes. The therapy requires 5 such sessions in total every 48 hours. That is followed by calculating an effectiveness index, a complete regression percentage and Pliss lymphosarcoma growth inhibition percentage.
EFFECT: method intensifies the antitumor effect of the thermal chemotherapy without increasing body toxicity.
FIELD: physics, optics.
SUBSTANCE: invention can be used in designing efficient devices for displaying alpha-numeric and graphic information. The increasing amount of visual information and advances in computer engineering require new-generation alpha-numeric displays. Disclosed is a quantum dot organic light-emitting diode with a monolayer of semiconductor quantum dots, lying at a distance from electron-conducting and hole-conducting layers, defined by an expression which links the Forster radius and the quantum dot radius. The active element is a monolayer of two-component (core-cladding) semiconductor nanoparticles capable of changing the diameter of the semiconductor core in the range of 2.0-6.0 nm and the thickness of the semiconductor cladding in the range of 1.0-3.0 nm in order to adjust the emission region in the range of 400-650 nm of the visible spectrum.
EFFECT: designing stable organic light-emitting diodes with the highest efficiency from the perspective of transmission of excitation energy from the donor to the active layer, said diodes having a controlled radiation spectrum in the visible wavelength range, which is crucial when designing new-generation alpha-numeric displays.
2 dwg, 1 tbl
SUBSTANCE: invention relates to production of organofilled polymer compositions and can be used in production of construction materials and in other sectors of the economy. The first version of the method of production involves grinding 10-90 wt % organic filler to particle size of 1-20000 mcm. The organic filler is then dried to moisture content of 0-50 wt % and mixed target additives in amount of 0-20 wt %. Components are then mixed with a high-molecular weight compound in amount of 10-90 wt % and a modifying additive is added in form of nanoparticles in amount of 0.0001-50 wt %, after granulation of the composition, to the whole mass of the obtained granulate by dry charging. The second version of the method of producing the polymer composition differs from the first version in that when modifying the polymer composition based on the organic filler, the granulate is added with an amount of the modifying additive in form of nanoparticles of up to 50% to the obtained composition at the compounding step.
EFFECT: invention shortens duration of the process and reduces labour input of production and cost.
2 cl, 5 ex
SUBSTANCE: method of making a pressure sensor involves depositing a first dielectric layer on the surface of a substrate, forming an electrical interconnection, depositing a second dielectric layer, forming a region for growing an array of carbon nanotubes in form of a depression on the substrate using lithography, forming a buffer layer, forming a functional layer over the buffer layer, said functional layer containing a catalyst for growing carbon nanotubes, removing the resist mask deposited during lithography, conducting synthesis of carbon nanotubes with plasma stimulation of the process of growing carbon nanotubes. A top sealing layer at least over the array of carbon nanotubes can be formed thereafter.
EFFECT: high reliability of operation of the sensitive element of the pressure sensor, high sensitivity of the pressure sensor, stable operation of the sensor irrespective of changes in parameters of the working medium.
18 cl, 4 dwg
SUBSTANCE: method involves synthesis of nanoparticles through a redox reaction while adding an enzyme for stabilising the formed nanoparticles directly into the reaction. The enzyme solution - chymotrypsin, concentration of which is selected from 0.02%, is mixed with a precursor solution of 0.013 M selenous acid or silver nitrate - 1%, 0.01%, 0.001%; the solutions are stirred and held at room temperature of 20°C or low temperature of 0°C for 30-60 minutes. A reducing agent - ascorbic acid or sodium borohydride - is then added to the reaction flask and the solutions are stirred and settled to complete the reaction.
EFFECT: invention enables to obtain stabilised nanoparticles of biogenic elements in form of molecular solutions that are resistant to precipitation over time at different pH, with a controlled diameter and high output.
1 tbl, 2 ex
FIELD: medicine, pharmaceutics.
SUBSTANCE: invention refers to a method for preparing a water suspension of silicon nanocrystalline particles for biomedical applications. The declared method is characterised by the fact that a porous silicon film of the thickness of 1 to 100 mcm and the porosity of 50 to 80% is formed on the surface of silicon plates. The film is formed by electrochemical etching in a solution containing 40-50% aqueous solution of fluoric acid and alcohol in ratio 1:1 to 1:5 for a period of time of 10 to 60 minutes at specific current 20 to 60 mA/cm2. The prepared silicon plates coated with a porous silicon layer is washed in distilled water, dried and placed in a container with distilled water. Then, they are exposed to ultrasound for more than 10 minutes at the intensity of the silicon plate exposure in water of 100 Wt/cm2 at frequency 23 kHz. This provides forming the stable suspension in distilled water from nanoparticles of the lateral dimension of 10 to 500 nm.
EFFECT: invention provides preparing the biocompaticle suspension of silicon nanoparticles that penetrate into living cells preserving its useful biological properties and luminescence.
4 dwg, 1 ex
FIELD: magnetic materials whose axial symmetry is used for imparting magnetic properties to materials.
SUBSTANCE: memory element has nanomagnetic materials whose axial symmetry is chosen to obtain high residual magnetic induction and respective coercive force. This enlarges body of information stored on information media.
EFFECT: enhanced speed of nonvolatile memory integrated circuits for computers of low power requirement.
4 cl, 8 dwg