A NEW ATTEMPT TO OBSERVE THE RESONANCE IN Ag<sup>109</sup>

Wildner, Wolfgang; Gonser, U.

doi:10.1051/jphyscol:1979216

Cited by 14 publications

(19 citation statements)

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“…The absence of a consistent mechanism explaining natural strong narrowing supported an opinion that the observation of this phenomenon was erroneous. At the same time, since neither temperature variations of the experimental geometry as in [15,16] nor instabilities as in [17] existed in [18], the experiments reported in [18] were consistently explained in [19,20]. It is important that the hyperfine structure line in [18] was assumed split in an external magnetic field H ex of about the Earth's field.…”

Section: Introductionmentioning

confidence: 73%

“…Then, D > 3 × 10 -14 cm 2 /s and k D > 2 × 10 6 ; i.e., the 88-keV line cannot be observed. Unobservability of this line at 293 K was previously attributed only to the smallness of the Mössbauer factor [15][16][17][18]. At ~4 K, k exp ~ 15.3 [20], k D < k exp , and τ 0 > τK 2 l 2 /3k exp ~ 3 × 10 3 s, which is five orders of magnitude larger than τ 0 at ~293 K. At the same time, τ 0 cannot increase infinitely as the temperature approaches E k v 0 K because of tunneling jumps of an atom between a site and a vacancy.…”

Section: Diffusion-induced Broadening K Dmentioning

confidence: 94%

“…Formula (2) from [19] gives the estimate |ψ n, s (0) Ag | 2 /|ψ n, s (0) Sn | 2 ~ (47/50) 3 where [Δp] S, A is the rms spread of pressures p at the bulk modulus of ~10 6 kG/cm 2 . The following conditions of the appearance of strong natural suppression can be obtained from inequalities (17) with the substituted estimate for Γ ch given by (15):…”

Section: Strong Natural Suppressionmentioning

confidence: 99%

“…The problem is that the artificial narrowing of lines in long-lived isomers is also problematic [8]. However, the analysis of the experiments performed more than 36 years ago with 109 Ag under natural conditions gave k ~ 10 rather than k > 10 6 , which indicated the natural strong narrowing of the line by a factor of ~10 6 (see [15][16][17][18] and references therein). At the same time, the observation of natural strong narrowing in [15][16][17] was considered questionable in [15,16,18].…”

Section: Introductionmentioning

confidence: 99%

“…This phenomenon is similar to the narrowing of NMR lines in a liquid. However, since γ-ray sources in [15][16][17][18] were solid rather than liquid, vibrations in them were insufficiently strong for the suppression of d fields from neighbors. Thus, natural strong narrowing is not similar to narrowing in NMR.…”

Section: Introductionmentioning

confidence: 99%

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Strong natural suppression of the monopole broadening of Mössbauer lines

Karyagin

2016

Jetp Lett.

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The study of natural strong narrowing of Mössbauer lines on long-lived isomers is continued. This phenomenon was first correctly detected in [Yu. D. Bayukov, A. V. Davydov, Yu. N. Isaev, G. R. Kartashov, M. M. Korotkov, and V. V. Migachev, JETP Lett. 90, 499 (2009)] and was consistently explained in [S. V. Karyagin, JETP Lett. 98, 174 (2013); 98, 695 (2013)]. Thus, natural strong narrowing is a new effect in spite of its 36-yr prehistory. Since natural strong narrowing is based on the collapse of the hyperfine structure owing to chaos in motion of the nuclear spin, "criteria of chaos" have been introduced for the exchange and virtual collapse mechanisms. Types of nuclei and media with these mechanisms have been indicated. It has been found that the lifetime τ of isomers appropriate for natural strong narrowing is limited by diffusion. The strong natural suppression (below 1/τ ~ 10 -2 s -1 ) of monopole (isomer, chemical) broadening has been revealed and explained.

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Section: Introductionmentioning

confidence: 73%

Section: Diffusion-induced Broadening K Dmentioning

confidence: 94%

Section: Strong Natural Suppressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Strong natural suppression of the monopole broadening of Mössbauer lines

Karyagin

2016

Jetp Lett.

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The Gravitational Red-Shift

Pound¹

1981

Topics in Current Physics

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

Alpatov¹,

Bizina²,

Давыдов³

et al. 1994

Meas Tech

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Preparation of l~ gamma sources implanted by thermal diffusion into a single crystal of silver is described. The source is intended for experiments on MOssbauer excitation of the long-lived isomeric state of 1~ with 88 keV energy. Two nondestructive methods are described for finding the depth of the implanted wgcd atoms. One is a general-purpose method and can be used to study the diffusion of a wide class of radioactive atoms. The second method is useful only for the investigation of boundary distributions of the radioactive diffusant.One attractive but exceedingly difficult applications of the MOssbauer effect is associated with gamma resonance excitation of long-lived isomeric states of nuclei. Though the first successive experiments in this field were carried in 1962-1963 [1], not significant advances have been made until now in such experiments. A detailed analysis of the reasons hampering the observation of the discussed process and of certain approaches to its investigation is given in [2]. Until now, besides the report [1] on the excitation of 1~ nuclei, several papers have been published on experiments with l~ using as gamma sources the radioactive isotopes l~[3] and l~ [4][5][6]. The authors of [1-3] developed a technique based on irradiation of an initially passive sample by gamma quanta from a strong source. Irradiation was carried out at low temperatures and the resulting gamma activity was of the resonant absorber was measured in conditions of low gamma background. Because of the long average lifetime of the absorbed nuclei (nearly 1 min for the mentioned silver isotopes), it was possible to place the absorber or source behind a thick enough radiation shield.Wildner and Gonzer [4] used a different method. The gamma source was prepared by implanting radioactive l~ into a single-crystal silver wafer using thermal diffusion. After cooling such a gamma source should exhibit MOssbauer selfabsorption of 88 keV gamma quanta by l~ nuclei. The authors reported observing self-absorption of about 0.1%. Such a large effect of gamma resonance self-absorption could have been observed only if the 88-keV gamma line did not broaden by not more than 30 times over the natural width of the isomeric state. Simultaneously, theoretical estimates [1, 2] and the results of [1] indicate that this broadening is at least 105-106 times. These results, and the lack of any convincing control experiments in, questioned the interpretation of the results of [4]. After the publication of [4], we have carried out experiments concerning the effect of temperature on the absorption of [7] gamma quanta in silver. The purpose of the experiments was to clarify if there are any anomalies in gamma quanta absorption by silver in the 4.2-77 K temperature range that can be associated, for example, with an unknown phase transition in silver that changes its density. However, no such anomalies were observed to within an error of the order of 0.01% for both gamma lines one of which is resonant for l~ nuclei and the other not. The experiment [7] i...

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A NEW ATTEMPT TO OBSERVE THE RESONANCE IN Ag¹⁰⁹

Cited by 14 publications

References 0 publications

Strong natural suppression of the monopole broadening of Mössbauer lines

Strong natural suppression of the monopole broadening of Mössbauer lines

The Gravitational Red-Shift

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

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A NEW ATTEMPT TO OBSERVE THE RESONANCE IN Ag109

Cited by 14 publications

References 0 publications

Strong natural suppression of the monopole broadening of Mössbauer lines

Strong natural suppression of the monopole broadening of Mössbauer lines

The Gravitational Red-Shift

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

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Product

Resources

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A NEW ATTEMPT TO OBSERVE THE RESONANCE IN Ag¹⁰⁹