A. V. Davydov

First experiments on the observation of gamma resonance of a long-lived 109m Ag isomer using a gravitational gamma spectrometer

The first measurements of the resonant Mössbauer self-absorption of the long-lived 109mAg isomer gamma rays as a function of the declination angle of the gamma beams from the horizontal direction are presented for a gamma source that represents a single-crystal silver plate doped with a parent 109Cd nuclide. The resonant absorption is manifested as a minimum of the counting rate ratio of the 109mAg and 241Am (control gamma source) gamma-line intensities at a zero-declination angle for one of two detectors and an angle of about 1° for another detector. The magnitude of the effect is in agreement with the results of our previous experiments performed on another setup. It follows, from the data obtained, that the angular width of the gamma-resonance profile is less than two degrees, which corresponds to a broadening factor of the Mössbauer gamma line of less than five. The value of this factor calculated from the measured relative magnitude of the 109mAg gamma-ray resonant absorption is 6.3−1.9+5.2.

Observation of the gamma resonance of a long-lived 109mAg isomer using a gravitational gamma-ray spectrometer

Experiments confirming the previous data on the small real width of the γ resonance of 109mAg have been performed with a gravitational gamma-ray spectrometer. The achieved resolution is eight orders of magnitude higher than that of Mössbauer spectrometers using gamma rays from a 57Fe nuclide. The theoretically predicted broadening of the Mössbauer gamma line of 109mAg by five orders of magnitude (due to the dipole-dipole interaction between the magnetic moments of neighboring nuclei) has not been observed.

Experiments on the gravity effect on the109Ag gamma resonance

The temperature dependence of the 109Ag γ-ray self-absorption was investigated for the horizontal and vertical directions of emission. The source was a single-crystal silver plate containing atoms of parent radionuclide 109Cd. Gamma-radiation of this γ-source and that of the monitoring γ-source, 57Co, were registered by a pair of Ge(Li)-detectors. As a result of cooling the source from 77 K to ~12 K a relative decrease was observed of the intensity of the horizontally emitted γ-rays equal to 0.00064±0.00044. For the vertical direction the corresponding intensity change turned out to be -0.00047±0.00051. Although these data, as one would see, give some evidence for the possible effect of the gravitation on the resonant γ-ray absorption, future measurements must show if these results aren’t a consequence of any apparatus effect. The ways for developments in this study are discussed and some hindrances are considered.

Initial studies of the gamma resonance of the 109mAg isomer with a gravitational gamma spectrometer

The problem of observing the Mössbauer resonance absorption of gamma rays from long-lived isomers is briefly outlined, first and foremost for 109mAg taken as an example. Experiments indicative of a small broadening of the Mössbauer gamma line of this isomer in metallic silver are described. This circumstance made it possible to develop and manufacture a gravitational gamma spectrometer and to perform the first experiments with it, which confirm once again the previous data on a small width of the gamma line in question. The broadening factor obtained from these data proved to be 6.3−1.9+5.2.

Temperature effect on the decay periods of long-lived 180mHf and 87mSr isomers

AbstractExperiments on measuring the decay periods of long-lived 180mHf and 87mSr isomers at room temperature and at 77 K in massive samples of HfO2, Sr(NO3)2, and SrCO3 are reported. The isomeric nuclear states were excited by irradiating the samples with neutrons from a Pu-Be source. According to the theory of V.I. Vysotski

Search for the Resonance Environmental Effect on the Decay Periods of Long-Lived Nuclear Isomers

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Check of the paradoxical results of experiments on resonance self-absorption of γ-quanta of109Ag in silver crystals

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Preparation and analysis of a109cd gamma source implanted into a silver single crystal

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