SU527651A1 - Radiospectrometer epr - Google Patents

Description

(54) ESR Radio Spectrometer

This goal is achieved by the fact that in an EPR spectrometer, a Shuch resonator, a recording unit, an electromagnet, an amplifier of an electromagnet current stabilizer. mismatch sensor, threshold device, modulator-demodulator / M-DM / amplifier, reference and modulating voltage source, charge capacitor, variable constant-voltage source and charge resistance, two synchronized switching devices are introduced through one of which the source of controlled voltage is connected to the threshold device, and through another switching device the source of the reference and modulating voltage is connected to an amplifier of the type modular mountain blew mountains. With a low switching frequency of the sweep of a polarizing magnetic field, a single-pole two-position switch can be used as the second switching device, and a two-pole two-position switch can be used as the first switching device. Switches can be synchronized, for example, by mechanical coupling. With a high switching frequency of the unwinding of a polarizing magnetic field, the switching devices and their synchronization between them can be performed electronically. FIG. 1 is a block diagram of a proposed radio spectrometer; in fig. 2 - switching device connecting it with other nodes of the radio spectrometer. The resonator 1 (see Fig. 1) connected to the recording unit 2 is located in the gap of the electromagnet 3. The electromagnet is connected to the amplifier 4 of the current stabilizer of the electromagnet. A mismatch sensor 5 connected to the electromagnet is connected via a capacitor 6 to the input of amplifier 4 and, in addition, is connected to the input of amplifier 7 (M-DM). The threshold device 8 is connected to the output of amplifier 7, through a switching device 9 (see figs. 1 and 2) to a direct current source 1O and through a resistance 11 with a charging capacitor 6 and an input of amplifier 4. Source of reference and modulating voltage 12 connected through a switching device 13 with an amplifier 7. Switching devices 9 and 1; synchronized with each other by communication 14.

The radio spectrometer operates as follows. Electromagnet 3 creates in the resonator 1 a polarizing magnetic field. As a result of the interaction of the sample polarized by the magnetic field in resonator 1 with the electromagnetic field of the microwave, an ESR signal is detected by block 2. When the sweep of the polarizing magnetic field is turned on, the threshold device 8 delivers through the charging resistance 11 from a DC source 1O the charging capacitor 6 and the input of the amplifier 4 are a voltage, the polarity of which is determined by the switching device 9. The output signal of the error sensor 5 is amplified by the amplifier 7 and is fed to the threshold device 8. The sign of the gain of the amplifier 7 is determined by the position of the switching device 13, which, depending on the position in which it is located (see Fig. 2), can supply the synchronous detector of the amplifier 7 with a reference voltage in phase with the voltage supplied to the modulator, or in antiphase. In one of two possible positions of the switching devices 13 and 9, after passing a predetermined sweep range, when the output signal of amplifier 7 reaches a certain threshold value, device 8 changes the polarity of the voltage applied to charging resistance 11 by the signal from amplifier 7, opposite to what the reverse sweep is achieved. After the input voltage of the threshold device 8 returns to zero, i.e. the intensity of the field of the electromagnet 3 reaches the level set before switching on the sweep, the threshold device 8 again supplies the voltage of the forward stroke of the sweep to the charge resistance 11. When switching the switching devices 14 synchronized 14, the switching devices 9 and 13 to another position, the threshold device 8 applies The charge resistance 11 voltage, which in the first position of the switching device 9 corresponded to reverse, and after passing the sweep range, went straight ahead, i.e. it changed the sign of the sweep. The operation of the threshold device 8 does not change, since in the second position of the switching device 13 the phase of the reference load on the synchronous detector of amplifier 7 changes, and the input voltage of the threshold device 8 has the same sign as in the first position of the switching device 13, a change in the sign of the sweep. Thus, in the proposed radio spectrometer, the EPR signal is recorded both at a sawtooth-increasing sweep and at a sawtooth falling sweep of the magnetic field - depending on the position of the switching devices 9 and 13. The presence of an ECR as a sawtooth falling sweep, hook and sawtooth age in the radio spectrometer sweep allows, when registering a weak signal immediately following an intensive signal, to begin recording the signal from the tail of the resonance line and stop recording before no intense signal. This allows you to extract information from the tails of the resonance lines without overloading the recording equipment with an intense signal. In addition, the presence of a saw-tooth, sweeping and warping, sweep in the EPR radio spectrometer allows starting the sweep from the side which is of interest and appears to be interesting for a short time and to record the whole spectrum in the case of the occurrence of this feature: In the proposed radio-spectrometer-EP, by comparing the spectra recorded with sawtooth, increasing and decreasing sweeps, it can be determined whether the asymmetry of the recorded spectrum is: the presence of a weak wide line or an instrument effect, such as drift or spurious integration. Finally, in the proposed EPR radio spectrometer, it is possible to record the spectrum in any direction of the sweep, which eliminates the difficulty of comparing the spectra with those given in the literature if they are recorded in different directions of the sweep. Ezobretenn formula The EPR radio spectrometer containing a resonator, a recording unit, an electromagnet, an electromagnet current stabilizer amplifier, a mismatch sensor, a threshold device, a charging capacitor and resistance, a modulator-demodulator amplifier, a source of reference and modulating voltage, and an adjustable constant voltage, characterized in that, in order to obtain both a linearly increasing and linearly falling sawtooth periodic sweep of a polarized magnetic field, it is equipped with two The mind is synchronized by switching devices, through one of which the source of the reference and modulating voltage is connected to an amplifier of the modular 5ggor-immodulator type, and the source of adjustable constant voltage is connected to the threshold device through another switching device. Sources of information taken into account in the examination: 1. Re-13O6 radioscope. Technical description and operating instructions. Leningrad, 1974 2. RE-13O6 radiospectrometer. Technical description and operating instructions, Leningrad, 1974

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