Apparatus for nuclear electron double resonance at 12500 gauss

1964 ◽  
Vol 279 (1379) ◽  
pp. 474-480 ◽  
Keyword(s):  
Double Resonance ◽  
Resolving Power ◽  
Microwave Cavity ◽  
Microwave Circuit ◽  
Nuclear Resonance ◽  
Radio Frequency Coil ◽  
Polar Solvents ◽  
Resonance Frequencies ◽  
Better Than ◽  
Double Resonances

Apparatus is described for measuring nuclear electron double resonances a t magnetic fields of 12500 G, in the microwave radiation of about 35000 Mc/s and at nuclear resonance frequencies from 3 to 60 Mc/s. The microwave circuit permits saturation of solutions of certain organic free radicals in solution in non-polar solvents when placed in a microwave cavity with a radio-frequency coil mounted inside. The resolving power of the nuclear resonance spectrometer is better than 1 in 10 8 . Recordings are presented to illustrate the performance of the apparatus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Resolution and measurement in the scanning electron microscope

1987 ◽  
Vol 45 ◽  
pp. 534-537 ◽  
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Engineering Design ◽  
Resolving Power ◽  
Practical Applications ◽  
Instrument Resolution ◽  
Accurate Definition ◽  
Definition Of ◽  
Scanning Electron ◽  
Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

scholarly journals ESA’s X-Ray Astronomy Mission, XMM

1990 ◽  
Vol 123 ◽  
pp. 129-140
Author(s):  
B.G. Taylor ◽  
A. Peacock
Keyword(s):  
Resolving Power ◽  
Science Program ◽  
Eccentric Orbit ◽  
Ccd Cameras ◽  
Optical Telescope ◽  
X Ray ◽  
Medium Resolution ◽  
Reflection Gratings ◽  
Better Than

AbstractESA’s X-ray Astronomy Mission, XMM, scheduled for launch in 1998, is the second of four cornerstones of ESA’s long term science program Horizon 2000. Covering the range from about 0.1 to 10 keV, it will provide a high throughput of 5000 cm2 at 7 keV with three independant telescopes, and have a spatial resolution better than 30 arcsec. Broadband spectrophotometry is provided by CCD cameras while reflection gratings provide medium resolution spectroscopy (resolving power of about 400) in the range 0.3–3 keV. Long uninterrupted observations will be made from the 24 hr period, highly eccentric orbit, reaching a sensitivity approaching 10−15 erg cm−2 s−1 in one orbit. A 30 cm UV/optical telescope is bore-sighted with the x-ray telescopes to provide simultaneous optical counterparts to the numerous serendipitous X-ray sources which will be detected during every observation.

Temperature dependence of nuclear resonance frequencies in the two-dimensional ferromagnet K2CuF4

1973 ◽  
Vol 43 (1) ◽  
pp. 39-41 ◽  
Author(s):  
Le Dang Khoi ◽  
P. Veillet ◽  
J-P. Renard ◽  
C. Jacoboni
Keyword(s):  
Temperature Dependence ◽  
Nuclear Resonance ◽  
Two Dimensional ◽  
Resonance Frequencies

scholarly journals A Microwave Fourier Transform Technique using Double Resonance Modulation

1987 ◽  
Vol 42 (4) ◽  
pp. 392-394 ◽  
Author(s):  
W. Stahl ◽  
J. Gripp ◽  
N. Heineking ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Double Resonance ◽  
Fourier Transform Spectroscopy ◽  
Resonance Technique ◽  
Double Resonances

We present a further modification of the double resonance technique in microwave FOURIER transform spectroscopy. The method is promising for the search of double resonances. It is demonstrated by three examples.

Using Hyperfine Interaction for the Structural Characterization of Amorphous Silicon

1986 ◽  
Vol 69 ◽  
Author(s):  
Martin Stutzmann ◽  
David K. Biegelsen
Keyword(s):  
Hyperfine Interaction ◽  
Amorphous Silicon ◽  
Dipolar Coupling ◽  
Double Resonance ◽  
Nuclear Spins ◽  
Electron Nuclear Double Resonance ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
Nuclear Spin System

AbstractThe hyperfine interaction between electronic and nuclear spins in hydrogenated amorphous silicon has been observed for the various paramagnetic defects in this material by electron spin resonance (ESR) and electron nuclear double resonance (ENDOR). The large hyperfine interaction between dangling bonds and 29Si as well as between donor electrons and 31p or 75 As nuclei can be resolved in ESR and provides direct information about the structure of the underlying electronic states. The smaller dipolar coupling of all paramagnetic states to more distant nuclei leads to an ENDOR response near the free nuclear resonance frequencies, which can be used to study the coupling of the electronic and nuclear spin system to the lattice phonons and to each other.

Electron spin resonance of paramagnetic impurities in antiferromagnetic compounds

1991 ◽  
Vol 433 (1888) ◽  
pp. 461-468 ◽  
Keyword(s):  
Internal Field ◽  
Host Lattice ◽  
Nuclear Resonance ◽  
Dipolar Field ◽  
Exchange Field ◽  
Paramagnetic Impurities ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
Impurity Ions ◽  
Impurity Ion

The possibility of magnetic resonance measurements on an impurity in an antiferromagnetic host lattice is discussed. The ion is subject to an internal field B int ; consisting of B dip , the dipolar field generated by the antiferromagnetic moments of the host ions, that can be calculated, and an exchange field B E . For a simple two sublattice antiferromagnet, two resonance frequencies should be observed; equations for their angular dependence are given, including the effect of hyperfine interaction. Impurity ions with Kramers doublets are discussed, together with ions with singlet ground states, for which enhanced nuclear resonance should be possible. A number of simple antiferromagnetic compounds of lanthanide (4f) ions that order at liquid helium temperatures are mentioned briefly, but for simplicity, the discussion is concentrated on GdVO 4 as the host lattice. A formula, based on the known exchange field in the host lattice, is deduced for its effect on the impurity ion.

scholarly journals Observational Approach and Perspective

1983 ◽  
Vol 71 ◽  
pp. 651-652
Author(s):  
G.S. Vaiana
Keyword(s):  
Angular Resolution ◽  
Resolving Power ◽  
Speckle Imaging ◽  
Lunar Occultation ◽  
Better Than

Goldberg: Well you did not cover more than half of my planned talk! (laughter). Let me comment on interferometric techniques, in particular speckle imaging which you mentioned. Doing speckle imaging with the largest telescopes now available will not give you better than the theoretical resolving power of the telescope. With a 4m telescope that is about 30 marc sec in the visible. That happens to be the radius of the supergiant Betelguese. So you are not going to achieve much with speckle imaging on these stars. One technique which has not been adequately exploited is that of lunar occultation which can give much better angular resolution than speckle, of the order of 2-3 marc sec. By using suitably chosen filters it may be possible to see structure on the disks of stars.

scholarly journals High Resolution Imaging Forty Years Ago

1994 ◽  
Vol 158 ◽  
pp. 337-341
Author(s):  
R. C. Jennison
Keyword(s):  
High Resolution ◽  
Point Sources ◽  
Resolving Power ◽  
High Angular Resolution ◽  
Electromagnetic Spectrum ◽  
High Resolution Imaging ◽  
Resolution Imaging ◽  
Optical Telescopes ◽  
Very High ◽  
Better Than

This conference is concerned with the very high resolution imaging of cosmic sources in many parts of the electromagnetic spectrum. Various techniques are now available and the equipment is often automated and highly sophisticated but the term ‘very high angular resolution’ is comparative. Many of the problems existed over forty years ago when the best resolving power was about half a degree and the two major radio ‘stars’ appeared to be point sources. Very high resolution imaging in those days was the struggle to reach one minute of arc and Hanbury Brown had set his sights on considerably better than one second of arc with the concept of the intensity interferometer. The dream was to achieve a resolving power comparable to that of optical telescopes.

scholarly journals The Microloop-Gap Resonator: A Novel Miniaturized Microwave Cavity for Double-Resonance Rubidium Atomic Clocks

2014 ◽  
Vol 14 (9) ◽  
pp. 3193-3200 ◽  
Author(s):  
Maddalena Violetti ◽  
Matthieu Pellaton ◽  
Christoph Affolderbach ◽  
Francesco Merli ◽  
Jean-Francois Zurcher ◽  
...  
Keyword(s):  
Double Resonance ◽  
Microwave Cavity ◽  
Atomic Clocks
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