SU725011A2 - Homodyne spectrometer of electron paramagnetic resonance - Google Patents

Description

The invention relates to techniques for electronic paramagnetic resonance (EPR) and can be used in radio engineering and other industries in the manufacture of EPR spectrometers.

Known homodyne EPR spectrometer according to ed. St. No. 655955, providing stabilization of sensitivity when changing microwave power in the working resonator, reducing dimensions and increasing efficiency and containing a microwave generator, a first circulator connected in series with it, which is connected on one side to the measuring channel, with a microwave reflective power attenuator (for example, in the form adjustable diaphragm), a second circulator, a measuring resonator, and on the other hand, is connected to a homodyne channel, with an absorbing microwave power attenuator, a phase shifter

Microwave, a microwave phase detector, the other input of which is connected to the resonator, and the output is connected to the registration system.

Usually in the process of changing power

The microwave in the measuring resonator of the EPR spectrometers using a signal channel attenuator changes the phase difference at the inputs of the microwave phase detector due to a phase change in the adjustable elements of the signal channel (in the reflective attenuator) or in the homodyne channel (in the absorbent attenuator). This requires an additional operation to correct the change in the microwave phase in the process of changing the power in the resonator using the microwave phase shifter of the homodyne channel, which complicates the process of tuning the EPR spectrometer.

The aim of the invention is to simplify the process of tuning the EPR spectrometer.

This is achieved by the fact that a reflective attenuator, similar to the attenuator of the signal channel, is additionally introduced into the homodyne channel of the spectrometer, and the control unit for changing the power of the additional attenuator is connected with the control unit for changing the power of the signal channel attenuator.

The identity of the design and the synchronization of power changes by the attenuators of the signal and homodyne channels ensures the constancy of the phase difference at the inputs of the phase detector in the process of changing the microwave power in the measuring resonator, as a result of which there is no need for constant adjustment of the phase in the homodyne channel. This solution simplifies the setup of the spectrometer.

The drawing shows a block diagram of one of the embodiments of the proposed spectrometer.

The EPR spectrometer contains a microwave power generator 1, a measuring channel, consisting of a series-connected first circulator 2, a reflective attenuator 3, a second circulator 4 and a measuring resonator 5; a homodyne channel, consisting of a valve 6, a second microwave power reflecting attenuator 7 and a phase shifter 8; a phase detector 9 and an EPR signal recording system 10. In addition, by means of a communication device 11, the power change control elements of both microwave attenuators 3 and 7 are interconnected. The design of the communication device And for a simultaneous change in power is determined by the type of reflective power attenuators 3 and 7 and it can be performed, for example, in the form of a mechanical joint of the size regulators of the openings of the waveguide diaphragms, in the form of two electrically combined adjustable current sources supplying power attenuators based on p— i — η diodes or in the form of a known device, synchronized with the tuning of the attenuator 3 of the signal channel, automatic power control in the homodyne channel by the attenuator 7 direct current phase detector 9.

The microwave power reflected from the attenuator 3 of the signal channel enters through the circulator 2 and the valve 6 to the input of the reflecting attenuator 7. In the process of regulating the power in the measuring resonator 5 using the attenuator 3, the magnitude of the power reflected from it also changes, and, accordingly, the amount of power coming from it 4 to the input of the attenuator 7. The part of the power reflected from the attenuator 7 is absorbed in the valve 6, and the transmitted power is used to provide the microwave bias of the detector 5 9. Ensuring the optimal level of bias on the detector 9 I wish to set up via a synchronous power attenuator attenuator 3 7 changes in homodyne channel.

In the signal and homodyne channels, the same type of reflective attenuators 3 and 7 are installed having identical phase characteristics. Therefore, the microwave phase shift in the signal channel when the power is attenuated by attenuator 3 will be equal to the microwave phase shift in the homodyne channel due to synchronous power control by attenuator 7. Thus, in the proposed device provides a constant 20 phase difference at the reference and signal inputs of the phase detector 9 in the process of regulating the power in the working resonator. In this regard, there is no need to reconfigure the phase shifter 8, which simplifies the process of tuning the EPR spectrometer as a whole, both in the mode of recording the EPR signal of dispersion and absorption.

Claims (1)

Claim Homodyne EPR spectrometer according to ed. St. No. 655955, characterized in that, in order to simplify the adjustment, an additional 35 reflective attenuator is added to the homodyne channel of the spectrometer, similar to the attenuator of the signal channel, and the power change control element is added. The attenuator is associated with a control element for changing the power of the attenuator 40 of the signal channel. f 7 Editor N. Kolyada Compiled by V. Pokatilov Tehred A. Kamyshnikova Corrector. E. Khmeleva Order 357/11 Ed. № 220 Circulation 1033 Subscribed Printing house, 2 Sapunova ave.