Mapping the Sensitive Volume of an Ion-Counting Nanodosimeter

We present two methods of independently mapping the dimensions of the sensitive volume in an ion-counting nanodosimeter. The first method is based on a calculational approach simulating the extraction of ions from the sensitive volume, and the second method on probing the sensitive volume with 250 MeV protons. Sensitive-volume maps obtained with both methods are compared and systematic errors inherent in both methods are quantified.Comment: 27 pages, 8 figures. Submitted to JINST, Jan. 16 200

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It is established that the average (over the number of bonds) intensity of the superexchange interaction of the Fe**3** plus ion with magnetic neighbors decreases by 10% on replacement of one oxygen ion with a fluorine ion, irrespective of the nature of the cation substitution

Long-range attraction between particles in dusty plasma and partial surface tension of dusty phase boundary

Effective potential of a charged dusty particle moving in homogeneous plasma has a negative part that provides attraction between similarly charged dusty particles. A depth of this potential well is great enough to ensure both stability of crystal structure of dusty plasma and sizable value of surface tension of a boundary surface of dusty region. The latter depends on the orientation of the surface relative to the counter-ion flow, namely, it is maximal and positive for the surface normal to the flow and minimal and negative for the surface along the flow. For the most cases of dusty plasma in a gas discharge, a value of the first of them is more than sufficient to ensure stability of lenticular dusty phase void oriented across the counter-ion flow.Comment: LATEX, REVTEX4, 7 pages, 6 figure

Synthesis of the aluminum-substituted hexaferrite SrFe 9.5Al 2.5O 19

The phase-formation processes involved in the synthesis of the hexagonal ferrite SrFe 9.5Al 2.5O 19 by solid-state reaction at 900°C for 5 min to 8 h were studied by x-ray diffraction and Mössbauer spectroscopy. The formation of the hexagonal ferrite at this temperature was found to take 3 h. The resultant material also contained SrAl 2O 4 and SrFeO 3-x, which suggests that, for the synthesis to reach completion, the heat-treatment temperature should be higher. The aluminum cations in the hexaferrite phase were shown to occupy, for the most part, positions 12k and 4f 1. © 1999 MAHK "Hayka/Interperiodica"

New and old N=8 superconformal field theories in three dimensions

We show that an infinite family of N=6 d=3 superconformal Chern-Simons-matter theories has hidden N=8 superconformal symmetry and hidden parity on the quantum level. This family of theories is different from the one found by Aharony, Bergman, Jafferis and Maldacena, as well as from the theories constructed by Bagger and Lambert, and Gustavsson. We also test several conjectural dualities between BLG theories and ABJ theories by comparing superconformal indices of these theories.Comment: 16 pages, late

Theory of quasienergetic phenomena in nuclear gamma resonance

An analysis is conducted of the resonance scattering of γ quanta when a ferromagnet scatterer experiences a single exposure to a strong radiofrequency field which is at resonance with respect to the Zeeman system of nuclear sublevels. The role of the quasienergetic spectrum arising in these conditions (analogous to the effect of a strong field in optics) in the formation of a scattering spectrum and, in particular, the intensity of the additional lines is demonstrated. The relation of the results obtained to those of other workers is discussed. © 1982 Plenum Publishing Corporation

Angular distribution of γ's scattered resonantly by nuclei in a solid

The resonant scattering of γ's by nuclei in a solid is analyzed with an account of the static hyperfine interaction of the nucleus. A general expression is obtained for the angular distribution of γ's for arbitrary ratios of the hyperfine splitting to the natural width of the Mossbauer line. The cases of the isotope Fe57 in single crystals and in polycrystalline samples are analyzed. © 1972 Consultants Bureau