Electron paramagnetic resonance spectrometre (versions)

FIELD: physics.

SUBSTANCE: first version of the electron paramagnetic resonance (EPR) spectrometre has a fixed frequency generator (1), a variable frequency generator (11), a first power divider (2), a second power divider (12), a third power divider (13), a channel switch (14), a first mixer (6), a second mixer (15), a low frequency amplifier (16), an oscilloscope (9), a circulator (3), a resonator (4), a magnetic system (5), an output direct current amplifier (7), a recording system (8) an a computer (10). The second version of the EPR spectrometer additionally has a low frequency power amplifier (17) and a frequency multiplier (18).

EFFECT: possibility of visualising settings and easier tuning of frequency of the resonator with a sample at a fixed working frequency of the microwave generator.

2 cl, 7 dwg

 

The invention relates to techniques for spectroscopy electron paramagnetic resonance (EPR) and may find application in studies of condensed materials and nanostructures by the EPR method in physics, chemistry, biology and other fields.

Known spectrometers electron paramagnetic resonance (EPR) with the filing of the microwave power on the investigated sample is placed in the resonator, are sources of microwave (MW) radiation with electronic frequency tuning (klystron, the generator on the Gunn diode). The advantage of such spectrometers is the visualization and simplicity of the installation process of the frequency tunable oscillator (GHG) emissions at the operating frequency of the resonator. The disadvantages of GHG emissions can be attributed to the quality of the spectrum, namely high phase noise, and low temperature stability frequency compared with the generator operating at a fixed frequency.

The frequency of the microwave radiation is usually tuned to the resonator and, as a rule, changes in registration of each of the EPR spectrum. Since there is no one fixed frequency, all EPR spectra are recorded at different frequencies. Thus, for a comparative analysis of the EPR spectra of the necessary additional equipment, allowing continuous measurement of the frequency with subsequent processing of the EPR spectra of d is I bring them to the same frequency, that is a time-consuming task, since it is often necessary for comparison of EPR spectra to recalculate them using complex mathematical operations, due to the necessity of diagonalizable matrix of the spin Hamiltonian.

Known spectrometer electron paramagnetic resonance 3-cm range (see J.J.Jiang, R.T.Weber, Ed. A.H. Heiss, D.P. Barr, ELEXSYS E 500 User.s Manual: Basic Operations Manual Version 2.0, Software Version 2.1, Part Number 8637060 Copyright © 2001 EPR Division Bruker Instruments, Inc. Billerica, MA USA)containing a microwave bridge, comprising a source of microwave radiation 3-cm range in the form of a klystron or generator on the Gunn diode, allowing to reconstruct the frequency of the microwave radiation by means of the control voltage.

Known for an EPR spectrometer 3-mm range, manufactured by Bruker (see BRUKER ELEXSIS. Electron Paramagnetic resonance E 600/680. User's Manual, Version 1.26, Written by G.G. Maresch 02.11.2004, Bruker Analytic GmbH, Rheinstetten, Germany), containing a generator of microwave channel of the UHF band tunable frequency microwave system with complex transportation of the microwave power in the waveguides 3-cm, 8-mm and 3-mm range, the resonator with the sample placed in a magnetic field, the possibility of visualization of the process of setting the frequency of the microwave generator to the frequency of the resonator and a relatively simple configuration system working frequency of the generator to the frequency of the resonator.

The disadvantage of the decree is the R above the EPR spectrometer is a relatively low frequency stability of work of tunable lasers compared to generators, operating at a fixed frequency. Greater than that of the generator with fixed frequency, the spectrum width of the tunable signal generator limits the resolution of the lines of the EPR spectra. The operating frequency is changed when the registration of each of the EPR spectrum, all spectra are recorded at different frequencies, the necessary additional equipment for continuous measurement of the frequency with subsequent processing of EPR spectra for bringing them to the same frequency in the comparison.

Known spectrometer electron paramagnetic resonance (see N. J. van der Meer, J.A. J.M. Disselhorst, J. Allgeier, J. Schmidt and W.Th. Wenckebach, Meas. Sci. Technol., 1, pp.396-400 (1990); J. A. J. M. Disselhorst, .J. van der Meer, .G. Poluektov, and J.Schmidt, J.Magn. Reson., Ser. A 115, pp.183-188, 1995), which coincides with the proposed technical solution for the greatest number of significant features and adopted for the prototype. The spectrometer prototype includes a generator of fixed frequency (high-stable generator of ultra-high frequency microwave radiation 3-mm range with a fixed frequency 94.9 GHz)attenuator, circulator, the resonator is placed in a magnetic field of the magnetic system, the mixer, the output of the DC amplifier, the registration system, oscilloscope and computer.

The spectrometer works in the following way. In the resonator is placed the sample. Microwave microwave power from the generator is and the fixed frequency is supplied to the power splitter, the main part of the power divider is fed to the circulator and then through a system of waveguides microwave pulses are received in the resonator with the sample placed in a magnetic field generated by the magnetic system. Reflected from the resonator with the sample signal in the opposite direction, the waveguide system on the circulator. The circulator directs the reflected signal in the mixer in the mixer receives the reference signal from the power splitter. Next, the resulting signal is sent through the output amplifier DC to the registration system, registration system, the signal goes to the computer and the oscilloscope. The device prototype pulsed EPR signal recorded on a signal electron spin echo in the microwave the microwave channel using the receiver of microwave radiation, that is implemented by the pulse scheme of registration of EPR. The spectrometer uses a fixed microwave frequency adjustment is performed by changing the amplitude and phase of the pulse sequence used in experiments on electron spin echo, in a moment of resonance tunable resonator directly on the oscilloscope. The advantage of the generator with fixed frequency is high stability, no need for frequency measurement upon registration, each is spectra EPR and thus, the simplification and cheapening of the device, ease of processing and comparison of different EPR spectra.

The disadvantage of the spectrometer prototype is the lack of electronic frequency tuning, which does not allow to visualize the setting of the spectrometer in the standard scheme of operation of an EPR spectrometer in continuous feed mode of the microwave power (continuous wave - cw) on the sample in the cavity of the spectrometer and thus to simplify it.

The task of the invention was to develop such an EPR spectrometer high-frequency microwave range, operating at a fixed frequency, which would provide the ability to render settings and simplified tuning frequency of the resonator with the sample at a fixed operating frequency of the microwave generator and thereby United the advantages of EPR spectrometers operating at a fixed operating frequency, with easy configuration of the EPR spectrometer with tunable microwave frequency.

The problem is solved by a group of inventions combined to form a single inventive concept.

In the first scenario the problem is solved in that an EPR spectrometer comprises a generator of fixed frequency, a generator of variable frequency, the first power divider, a second divider power, the third power splitter, switch channels, the first mixer, W is Roy mixer, low-frequency amplifier, oscilloscope; a circulator, a resonator, a magnetic system, the output of the DC amplifier, and a computer. The output of the fixed frequency generator connected to the input of the first power splitter, a first output of which is connected to the first input channel switch, the output of which is connected to the input of the third power splitter. The first output of the third power splitter connected to the first input of the second mixer, the second output of the third power splitter connected to the input of the circulator. Input/output circulator is connected to the input/output resonator, and the output of the circulator is connected to a second input of the second mixer. The output of the second mixer connected to the input of the output of the DC amplifier, the first output of which is connected to the first input of the oscilloscope, and the second output of the output amplifier DC current through the registration system connected to the computer. The output of the generator is a variable frequency is connected to the input of the second power splitter, the first output of which is connected to the second input channel switch, and a second output connected to the first input of the first mixer. The second input of the first mixer connected to the second output of the first power splitter, the output of the first mixer through a low frequency amplifier connected to the second input of the oscilloscope.

In the first is a version of an EPR spectrometer is used, the mixing frequency of the fixed frequency generator and generator variable frequency high frequency the appropriate working frequency (RF) of an EPR spectrometer. To do this in an EPR spectrometer also includes a generator of variable frequency, a second power splitter, the third power splitter, switch channels, the second mixer and low-pass amplifier.

On the second version the problem is solved in that an EPR spectrometer comprises a generator of fixed frequency, a generator of variable frequency, the first power divider, a second divider power, the third power splitter, switch channels, the first mixer, the second mixer, subwoofer amplifier, oscilloscope, air circulator, amplifier low frequency power, a frequency multiplier, a resonator, a magnetic system, the output of the DC amplifier, and a computer. The output of the fixed frequency generator connected to the input of the first power splitter, a first output of which is connected to the first input channel switch, the output of which is connected to the input of the amplifier low frequency power, the output of which is connected through a frequency multiplier with input of the third power splitter. The first output of the third power splitter connected to the first input of the second mixer, the second output of the third power splitter connected to the input of the circulator. Input/output circulator is connected to the input/output resonator, and the output of the circulator is connected to the second input of the second mixer. The output of the second mixer connected to the input of the output of the DC amplifier, the first output of which is connected to the first input of the oscilloscope, and the second output of the output amplifier DC current through the registration system connected to the computer. The output of the generator is a variable frequency is connected to the input of the second power splitter, the first output of which is connected to the second input channel switch, and a second output connected to the first input of the first mixer. The second input of the first mixer connected to the second output of the first power splitter, the output of the first mixer through a low frequency amplifier connected to the second input of the oscilloscope.

To improve reliability and speed up the setup of the microwave system needs to be linked to the frequency of the resonator to the oscillator frequency fixed frequency. Was developed to obtain a "label" on the oscilloscope screen, corresponding to the moment of equality of the frequencies of the fixed frequency generator and generator variable frequency. The basis of this methodology based on a mixing frequency of the fixed frequency generator and generator variable frequency on the high frequency mixer with registration difference frequency.

The claimed technical solution is illustrated by drawings, where

figure 1 presents a block diagram of an EPR spectrometer prototype;

figure 2 image is a block diagram of the first variant of the proposed EPR spectrometer;

figure 3 shows the block diagram of the second variant of the proposed EPR spectrometer;

figure 4 presents an illustration of obtaining "label" frequency (a) frequency dependence of the two generators from the control voltage, (b) dependence on the control voltage difference frequency (beats); the inset shows the bandwidth of the low-frequency amplifier, used for registration of the mixed two signal generators (C) is the output signal of the amplifier;

figure 5 shows the oscillogram showing the signal of the microwave power reflected from the resonator spectrometer (a) and label the frequency of the oscillator, fixed frequency (b); failure corresponds to the resonance curve of the resonator, its frequency is tuned to the frequency of the fixed frequency generator 94 GHz;

figure 6 shows a case where the configuration of the resonator to the frequency of the main generator 94 GHz; (a) signal reflected from the resonator of the microwave power, (b) - label with matching fixed frequency and tunable lasers;

figure 7 shows the typical dependence of the frequency tunable oscillator from the control voltage.

A block diagram of an EPR spectrometer prototype (figure 1) given the following designations: a generator of fixed frequency (GFC) 1, the first power splitter (DM1) 2, the circulator (C) 3, the resonator (R) 4, placed in mA the magnetic field of the magnetic system 5; the first mixer (CM1) 6, the output of the DC amplifier (WOPT) 7, the registration system (SRS) 8, oscilloscope (OG) 9 and the computer (To)10.

Improving the reliability and acceleration settings of the microwave system in the present EPR spectrometer is achieved by the binding frequency of the resonator (R) 4 to the oscillator frequency fixed frequency (GFC) 1 (high-stability oscillator 94 GHz).

In the first scenario (see figure 2) an EPR spectrometer comprises a generator of fixed frequency (GFC) 1, the generator of variable frequency (THEMES) 11, voltage controlled, the first power splitter (DM1) 2, the second power splitter (DM2) 12, a third power splitter (DM3on 13, channel selector (PC) 14, the first mixer (CM1) 6, a second mixer (CM2) 15, the low-frequency power (NU) 16, oscilloscope (OG) 9; a circulator (C) 3, the resonator (R) 4, a magnetic system 5, the output of the DC amplifier (WOPT) 7, the registration system (SRS) 8 and the computer (To) 10. Output GFC 1 is connected to the input of a DM12, the first output of which is connected to the first input of the PC 14, the output of which is connected to the input of DM313. The first output DM313 connected to the first input CM215, the second output DM313 connected to the input of C 3, input/output which is connected to the input/output P 4, and the output C 3 is connected to a second input CM215. Output CM215 is connected to the input IN THE PT 7, the first output of which is connected to the first input of the EXHAUST gas 9 and the second output WOPT WED 7 through 8 are connected to the 10. The output of HRÜ 11 is connected to the input DM212, the first output of which is connected to the second input of the PC 14, and a second output connected to the first input CM16, the second input is connected to the second output DM12, the output CM16 through WELL 16 is connected to a second input of the EXHAUST gas 9. In the first variant implementation of an EPR spectrometer is frequency mixing GFC 1 and THEMES 11 on the high-frequency mixer CM215 registration difference frequency.

The first version of the proposed EPR spectrometer works in the following way. Microwave power from GFCI 1 on the first channel (1) is supplied to DM12, and from HRÜ 11, the frequency of which is controlled by the voltage on the second channel (2) is fed to DM212 and then a small part of the power selected from 1 and 2 goes to CM16, next to WELL 16 and the second EXHAUST gas inlet 9. Basic microwave signal with DM12 and DM212 is supplied to the PC 14, open to signal with THEMES 11. Then through DM313, which includes the standard elements of the corresponding wavelength range: slotted bridge, Phaser, gate, attenuator and termination, the microwave signal is applied to C 3, which sends a direct signal R 4, placed in the magnetic field of the magnetic system 5, and reflected from P 4 signal will occupait through C 3 CM 215, further WOPT 7, from which the signal arrives at the first input of the EXHAUST gas 9, and CF 8 and 10.

In the second case, presented in figure 3, the mixing frequency is carried out at a low frequency relative to the operating frequency (RF)equal to RF/N, that is, to frequency multiplication by a factor N to produce high RF spectrometer.

Declare an EPR spectrometer (see figure 3) on the second version contains GFC 1 at a fixed frequency, low relative to RF and equal to RF/N, HRÜ 11 at a variable rate equal to RF/N, DM12, DM212, DM313, PC-14, CM16, CM215 WELL 16, the EXHAUST gas 9, C 3, R 4, in which is placed the sample, a magnetic system 5, WOPT 7, WED 8, and 10. In addition, the spectrometer includes a low-frequency amplifier power (CNM) 17 and the frequency multiplier (MIND) 18, which converts the low frequency in the UHF output corresponding to the operating frequency of an EPR spectrometer. Output GFC 1 is connected to the input of a DM12, the first output of which is connected to the first input of the PC 14, the output of which is connected to the input of CNM 17, the output of which is connected through the MIND 18 to the input DM313. The first output DM313 connected to the first input CM215, the second output DM313 is connected to the input C 3. Input/output C 3 is connected to the input/output P 4, and the output of the circulator C 3 is connected to a second input CM215. Output CM215 connected to the input of WOPT 7, the first of which is dinen to the first input of the EXHAUST gas 9, and the second output WOPT WED 7 through 8 are connected to the 10. The output of HRÜ 11 is connected to the input DM212, the first output of which is connected to the second input of the PC 14, and the second output DM212 connected to the first input CM16. The second input CM16 is connected to the second output DM12, the output CM16 through WELL 16 is connected to a second input of the EXHAUST gas 9.

The second variant of the proposed EPR spectrometer works in the following way. Power is generated LLC 1 fixed frequency, low in relation to the operating frequency and is equal to RF/N (channel 1) and 11 THEMES with variable frequency, including in the working range of the frequency of the RF/N (second channel To 2), the frequency of which is controlled by a sawtooth voltage. A small part of the power through DM12, DM212 for channels 1 and 2 respectively served on CM16, then the signal SM16 is supplied through the WELL 16 to the second input channel of the EXHAUST gas 9; the main part of the power channels 1 and 2 in the interval of frequencies, which includes RF/N is fed to the PC 14, open to signal with THEMES 11. From the PC 14 via CNM 17 power is supplied to MIND 18 with the multiplication factor N (in the example N=13), where the frequency is low compared to the operating frequency (RF/N), converts the microwave power corresponding to the operating frequency of the RF EPR spectrometer (as an example RF=94 GHz), which then goes on DM313; DM313 base the main part of the microwave power supplied to C 3, who directs this power in the forward direction on the microwave path on R 4 with the sample placed in a static magnetic field magnet system 5 and in the opposite direction reflected from R 4 sample microwave microwave signal on the same microwave path through C 3 goes on CM215 microwave signals at the operating frequency, which also receives a reference microwave signal with DM313, a further part of the signal at WOPT 7, from which the signal arrives at the first input of the EXHAUST gas 9, the main signal comes from VOPT 7 on CF 8 and further To 10.

Was made a prototype of the proposed EPR spectrometer operating at a fixed operating frequency of 94 GHz, created high-stability oscillator. Was assembled microwave unit, in which the mixing frequency occurs at frequencies in the region of 7 GHz, equal to RF/N, where N=13, i.e. to the frequency multiplication, in which part of the power generators in the region of 7 GHz to the fixed frequency generator and generator of variable frequency, voltage controlled, is supplied to the mixer and then to the output amplifier to develop a differential signal frequency - label. This signal is fed to one input of a two-channel oscilloscope, to the second input of which receives the signal from the receiver of the microwave unit. During the reconstruction work of the resonator is achieved ppsr is doing its frequency is labeled with a working frequency of the generator. Then e is switching from configuration mode, which involves an auxiliary generator with variable frequency, operating mode, which uses only high-stability oscillator with fixed frequency.

The development of a new microwave circuit block, in which the receive signal ("label" frequency) when the frequency of the fixed frequency generator and generator of variable frequency, voltage controlled, provided the visualization of the configuration process and thus significantly speed up, simplify and make more reliable the configuration of the microstrip microwave tract of an EPR spectrometer. The original method is to use to configure microwave microwave tract generator of variable frequency, voltage controlled, monitored on the oscilloscope screen of resonance absorption of the resonator and the restructuring of its frequency to match the "mark" of the working frequency oscillator having a fixed frequency. Next, the communication settings of the resonator. Figure 4 presents an illustration of obtaining "label" frequency (a) frequency dependence of the two generators from the control voltage, (b) dependence on the control voltage difference frequency (beats); the inset shows the bandwidth of the low-frequency amplifier, modulating sovannara for registration of a mixed signal of the two generators, (C) is the output signal of the amplifier.

Figure 5 shows the waveform of the resonance curve of the resonator (a) and "mark" frequency (b). The coincidence of the failure of the resonator with a "label" refers to the adjustment of the working resonator to the frequency of the stable oscillator 94 GHz.

Real-microwave circuit in which transitions are used with waveguides 3-mm band waveguides 8-mm range, the connection waveguides and bends, observed failures of the signal reflected microwave power from the frequency associated with parasitic reflections in the waveguide path. Such resonances are seen at 6 to the right and to the left of the resonance curve of the resonator (a) at the temperature of liquid helium in the field of superconducting magnet shown to "label" the working frequency of the generator (b). The presence of the tag frequency has enabled the reliable setting of the working cavity and receiving signals EPR. The frequency of the resonator is tuned to the frequency of the main generator 94 GHz (narrow dip in the center coincides with the mark). Figure 6 shows a typical dependence of the frequency generator of variable frequency from the control voltage.

1. The spectrometer electron paramagnetic resonance, comprising a generator of fixed frequency, a generator of variable frequency, the first power divider, a second divider power, the third power splitter, switch the channel is in, the first mixer, the second mixer, subwoofer amplifier, oscilloscope, air circulator, a resonator, a magnetic system, the output of the DC amplifier, and a computer, and the output of the fixed frequency generator connected to the input of the first power splitter, a first output of which is connected to the first input channel switch, the output of which is connected to the input of the third power splitter, the first output of the third power splitter connected to the first input of the second mixer, the second output of the third power splitter connected to the input of the circulator, the input/output of which is connected to the input/output resonator, and the output of the circulator is connected to a second input a second mixer, the output of the second mixer connected to the input of the output of the DC amplifier, the first output of which is connected to the first input of the oscilloscope, and the second output of the output amplifier DC current through the registration system is connected to the computer, the output of the generator is a variable frequency is connected to the input of the second power splitter, the first output of which is connected to the second input channel switch, and a second output connected to the first input of the first mixer, the second input is connected to the second output of the first power splitter, the output of the first mixer through a low frequency amplifier connected to the second input of the m-test.

2. The spectrometer electron paramagnetic resonance, comprising a generator of fixed frequency, a generator of variable frequency, the first power divider, a second divider power, the third power splitter, switch channels, the first mixer, the second mixer, subwoofer amplifier, oscilloscope, air circulator, amplifier low frequency power, a frequency multiplier, a resonator, a magnetic system, the output of the DC amplifier, and a computer, and the output of the fixed frequency generator connected to the input of the first power splitter, a first output of which is connected to the first input channel, output channel switch connected to the input of the amplifier low frequency power, the output of which is connected through a frequency multiplier with input of the third power splitter, the first output of the third power splitter connected to the first input of the second mixer, the second output of the third power splitter connected to the input of the circulator, the input/output of the circulator is connected to the input/output resonator, and the output of the circulator is connected to a second input of the second mixer, the output of the second mixer connected to the input of the output of the DC amplifier, the first output of which is connected to the first input of the oscilloscope, and the second output of the output amplifier DC current through the system is registracii connected to the computer; the output of the generator is a variable frequency is connected to the input of the second power splitter, the first output of which is connected to the second input channel switch, and a second output connected to the first input of the first mixer, the second input of the first mixer connected to the second output of the first power splitter, the output of the first mixer through a low frequency amplifier connected to the second input of the oscilloscope.



 

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FIELD: inspection of degree of lacing of polyethylene.

SUBSTANCE: tested and reference samples are placed into resonator of electron paramagnetic resonance spectrometer, spectrum of absorption of electron paramagnetic resonance is recorded. Amplitude of derivative and width of absorption line of tested and standard samples is found from spectrum recorded correspondingly to subsequent determination of degree of lacing from formula K=I'ΔH2mref/I'refΔH2refm, where I' and I'ref are amplitudes of derivative of absorption line of tested and reference sample, ΔH and ΔHref is width of absorption lines of tested and reference samples, m and mref are masses of tested and reference samples.

EFFECT: improved precision of inspection; simplified method of inspection; improved efficiency of operation.

FIELD: medicine.

SUBSTANCE: invention refers to pharmacy, namely identification, estimation of quality and safety of original and reproduced medical products. Described comparative estimation of physiological activity of original medical products and reproduced medical products or related preparations implies that by means of EPR spectroscopy and spin probes influence of these products on erythrocyte, lymphocyte and thrombocyte membrane structures released of the same blood sample depending on active component concentration in solution and contact time are examined by comparison of corresponding data obtained within concentration corresponding to maximum therapeutic dose.

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FIELD: nanotechnologies.

SUBSTANCE: nanodiamond is placed into installation for annealing, hydrogen is passed through and maintained at the temperature selected from the range of (900÷1100) °C, cooled down to room temperature. X-ray diffraction pattern is taken. Additionally spectrum of electronic paramagnetic resonance (EPR) is registered at room temperature. Availability of metal phases is identified.

EFFECT: invention makes it possible to increase sensitivity of magnetic admixtures content detection in nanodiamonds of detonation synthesis.

2 cl, 6 ex

FIELD: physics.

SUBSTANCE: calibration sample is put into a measuring resonator, which gives an anisotropic spectrum (EPR), made from a rutile monocrystal TiO2 which contains Fe3+ ions in amount of 0.01-0.5 wt %. The calibration sample is turned in a magnetic field until appearance of an EPR anisotropic spectrum of Fe3+ ions whose lines are recorded and the EPR spectrometre is set using the said lines to maximum signal-to-noise ratio by moving the matching piston of the resonator and moving the bottom wall of the resonator in order to adjust the frequency of the resonator.

EFFECT: simple process of tuning and calibrating an electron paramagnetic resonance spectrometre.

4 cl, 2 dwg

FIELD: physics.

SUBSTANCE: electron paramagnetic resonance spectrometre has a microwave generator (1) in the 90-100 GHz range, a microwave bridge (20), a system for transmitting microwave power to a sample in form of series-arranged first 3 mm waveguide (2), first horn antenna (3), at least one dielectric lens (4), second horn antenna (5) whose horn faces the horn of the first horn antenna (3), and a second 3 mm waveguide (6). The spectrometre also has a resonator (7), having a piston (8) and sample holder (9), a microwave signal detector (10), a synchronous detector (11), a magnetic field modulation generator (12), modulation coils (13), a magnetic field scan unit (14), a superconducting magnet (15), a cryogenic system (16) for maintaining temperature of liquid helium, having an optical window (17) and a control unit (18). The superconducting magnet (15), modulation coils (13), second horn antenna (5), second 3 mm waveguide (6) and resonator (7) are placed in the cryogenic system (16). The second horn antenna (5) is placed opposite the optical window (17) of the cryogenic system and is connected through the second 3 mm waveguide (5) to the resonator through a coupling aperture. The first horn antenna (3) and at least one dielectric lens (4) are fitted outside the cryogenic system (16) opposite its optical window (17).

EFFECT: reduced heat losses in the cryostat and reduced amount of reflected microwave power.

3 cl, 2 dwg

FIELD: physics.

SUBSTANCE: first version of the electron paramagnetic resonance (EPR) spectrometre has a fixed frequency generator (1), a variable frequency generator (11), a first power divider (2), a second power divider (12), a third power divider (13), a channel switch (14), a first mixer (6), a second mixer (15), a low frequency amplifier (16), an oscilloscope (9), a circulator (3), a resonator (4), a magnetic system (5), an output direct current amplifier (7), a recording system (8) an a computer (10). The second version of the EPR spectrometer additionally has a low frequency power amplifier (17) and a frequency multiplier (18).

EFFECT: possibility of visualising settings and easier tuning of frequency of the resonator with a sample at a fixed working frequency of the microwave generator.

2 cl, 7 dwg

FIELD: chemistry.

SUBSTANCE: hydroxyapatite sample is irradiated with X-ray, gamma or electron beams, followed by recording the EPR spectrum resulting from exposure of paramagnetic centres on a certified EPR spectrometre. Spectral characteristics the observed EPR spectrum (number of observed lines and their position) are calculated while monitoring measurement error and comparing the obtained spectral characteristics with known spectral characteristics of nitrogen radicals in (poly)crystalline compounds.

EFFECT: possibility of qualitative and quantitative analysis of nitrogen compounds in substances with the structure of hydroxyapatites.

2 dwg

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