SU441507A1 - Electron Paramagnetic Resonance Spectrometer - Google Patents

Description

Isolation refers to electron paramagnetic resonance (EPR) techniques.

In the known EPR radio spectrometers, the internal cavity of the measuring resonator is open to the access of ambient atmospheric air. GpI studies carried out in a wide range of temperatures, heating of the sample under study (for example, by high-temperature measurements) is accompanied by oxidation of the internal surfaces of the resonator and the appearance of an additional EPR hardware signal. In the low-temperature region, the cooling of the sample is accompanied by condensation of atmospheric moisture on the internal surfaces of the resonator. Due to large dielectric losses in condensed water, the quality factor of the resonator and the sensitivity of the spectrometer associated with it decrease. In studies of wide EPR signals, the sensitivity of the spectrometer is proportional to the amplitude of the high-frequency (B.4) modulation. Increased sensitivity due to an increase in the amplitude of V.Ch. modulation is limited to heating by V.Ch. modulation loops.

The purpose of the invention is to maintain the sensitivity of the spectrometer during multiple wide-range temperature studies.

The goal is achieved by the fact that in the proposed radio spectrometer, the internal volume of the resonator is connected to an additional chamber and, together with it, is hermetically sealed from the surrounding atmosphere. The walls of the chamber are thermostated by any known method, and an additional device is introduced that circulates in the system a resonator — a chamber of temperature-stabilizing gas. The gas must be diamagnetic and thoroughly cleaned from traces of oxygen and moisture. Sealing the internal volume of the cavity allows

modulate loops of hollow tubes and let the cooling water inside the tubes.

If, according to the experimental conditions, the sealing of the internal cavity of the resonator cannot be achieved, then the following options are possible: the gas filling the central cavity is introduced under a pressure exceeding the atmospheric one; The modulation loops are cooled with hot water, the temperature of which is above the dew point for a given atmospheric humidity.

If the sample is examined in the low-temperature region, then a gas, cooling sample can simultaneously be used to fill the resonator. The drawing shows schematically the proposed radio spectrometer in such an embodiment.

The radio spectrometer contains a volumetric measuring resonator J HF and modulation loops 2; preliminary chamber 3; tube 4, holding the test sample 5 and at the same time sealing the internal cavity of the resonator from the surrounding atmosphere; Dewar tube for thermostating the specimen; an additional chamber 7 for thermostating the gas filling the resonator. Water and gas, respectively, are fed through inlets 8 and 9, water is discharged through pipe 10.

The sensitivity of a radio spectrometer in the study of wide EPR lines can be increased several times only by increasing the total frequency of the RF modulation of the magnetic field.

;. PRINTERING INVENTIONS

Claims (3)

1. Radio spectrometer electronic paramagnetic resonance, containing measuring volume resonator .tor connected to the source of microwave oscillations, block high-frequency modulation of the magnetic field, supplying high-frequency modulation loops located inside the resonator, creating an electromagnet polarizing the magnetic field, in the interpolar gap of which a measuring resonator is located, which differs in body1, the resonator is connected to an additional temperature-stabilizing chaser and, with it, is hermetically isolated from the surrounding atmosphere. EASURES; at the same time, the spectrometer is equipped with an additional device ensuring the circulation of the temperature-stabilizing gas in the closed space of the resonator - chamber. 2. A radio spectrometer according to claim I, characterized in that diamagnetic gas purified from traces of moisture and oxygen was used as a temperature stabilizing gas. 3.Radio spectrometer pp 1 and 2, characterized in that the high-frequency modulation loops are hollow for the passage of the refrigerant.