Nuclear gamma

The Mossbauer effect involves the resonance fluorescence of nuclear gamma radiation and can be observed during recoilless emission and absorption of radiation in solids. It can be exploited as a spectroscopic method by observing chemically dependent hyperfine interactions. The recent determination of the nuclear radius term in the isomer shift equation for shows that the isomer shift becomes more positive with increasing s electron density at the nucleus. Detailed studies of the temperature dependence of the recoil-free fraction in and labeled Sn/ show that the characteristic Mossbauer temperatures Om, are different for the two atoms. These results are typical of the kind of chemical information which can be obtained from Mossbauer spectra. 

As of September 1966, nuclear gamma ray resonance (the Mossbauer eflFect) has been observed in at least nine of the rare earth elements leoDy, leiDy, i Er, i iEu, 237Np, i" Tb, Tm,... 

They have been thrust to the forefront of cosmology, a boon for nuclear astrophysics The satellite INTEGRAL, dedicated to nuclear gamma-ray astronomy and on the point of spreading its wings, carries all the hopes and aspirations of the scientific community to which 1 belong. 

A new era of European supremacy will open up in the domain of nuclear gamma astronomy, for no large-scale project has been proposed across the Atlantic to take up where the CGRO observatory left off. Let us hope that European science will make the most of this boon. ... 

The best illustration of radioactive astronomy is titanium-44. We shall take it as the archetype of a good radioactive isotope. It is relatively abundant and has a reasonable lifetime of around 100 years, neither too long, nor too short. Only aluminium-26 can rival it in this respect and nuclear gamma astronomy has already reaped some of the rewards (see Fig. 4.4). 

Photoelectron, Nuclear Gamma-Ray and Infrared Absorption Spectroscopic Studies of Neptunium in Sodium Silicate Glass, B.W. Veal, W.T. Camall, B.D. Dunlap, A.W. Mitchell, and D.J. Lam (Eds.), In High Tech Ceramics, P. Vincenzini (Ed.), Elsevier Science Publisher, Amsterdam, 1987, pp. 2903-2910. 

Litvinov V.S., Carakishev S.D., Ovchinnikov V.D. (1982), Nuclear gamma-resonance spectroscopy of alloys, Moscow, Metallurgy, Russia, 144. 

Consequently, Au(in) and Au(I) compounds have been the subject of extensive investigations by nuclear gamma resonance spectroscopy. The results revealed a dependence of the isomer shift on the oxidation state similar to that found in compounds of the 3d, 4d, and 5d transition elements, e. g., "Fe, Ru, Ir, and Os. On the other hand, appreciable variation of the isomer shift within the same oxidation state was observed for Au(I) and Au(ni) compounds, much as in the cases of Ru(n) and Ru(m), Ir(ni), and Fe(H) low-spin complexes, indicating a marked dependence of the isomer shift upon the nature of the ligands. 

Magnetic and nuclear gamma resonance (NGR) parameters of EuO Fe composites are studied. Their properties really meet the requirements imposed on the use of them as spin injectors in semiconductor spin-electronic structures capable of operating under normal conditions at room temperatures. 

O.C.Kistner, A.W.Sunvar, Evidence for Quadropole Interaction of Fc and Influence of Chemical Binding on Nuclear Gamma Ray Energy, Phys.Rcvi it, 4 (1960)412-415,... 

Mossbauer spectroscopy measures the resonant absorption of nuclear gamma rays involved with transitions between the ground and excited states of atomic nuclei with nonzero angular momenta. The precise energy of such transitions is... 

Fig. 1.3 The resonance overlap for free-atom nuclear gamma resonance is small and is shown shaded in black.

The scientific potential of nuclear gamma-ray astronomy is outlined in section 2. In sections 3 instruments for spectroscopy in the low and medium gamma-ray channel are presented modulating aperture systems, Compton telescopes and diffraction lens telescopes. The three techniques actually reflect our current perception of light itself - they are based on the principles of geometrical optics, quantum optics and wave optics, respectively. 

The study of nuclear gamma-ray lines that are produced by isomeric transitions in Ge detectors offers the possibility of estimating the neutron spectrum inside the shield. This process constitutes an important source of background in gamma-ray spectrometers flown in the upper atmosphere and in earth orbit. 

Photoelectron, Nuclear Gamma-Ray and Infrared Absorption Spectroscopic Studies of Neptunium in Sodium Silicate Glass, B.W. Veal, W.T. CarnaU, BD. Dunlap, A.W. 

Ale] Electron diffraction, nuclear gamma resonance Order-disorder kinetics in Co-Fe equiatomic alloys + V... 

Ser] Nuclear gamma and nuclear magnetic resonance 23 mass% Co, 29 mass% Cr, Fe = bal. 540-630°C spinodal decomposition in bcc phase... 

Kaipov DK (1976) Nuclear gamma resonance and its related processes. Naul, Alma Ata Kajcsos Z, Alflen M, Spiering H, Gutlich P, Albrecht R, Schulze R, Kurz R (1986) Hyperfine Interact 29 1551 Kajcsos Z, Sauer Ch, Holz rth A, Kurz R, Zinn W, Ligtenberg MAC, Van Aller G (1988) Nucl Instr Meth Phys Res B 34 384... 

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