Messung des 3H-Betaspektrums und Bestimmung der Obergrenze für die Ruhemasse des elektronischen Antineutrinos / Measurement of the H3-Betaspectrum and Determination of an Upper Limit for the Electronic Antineutrino Rest Mass

1974 ◽  
Vol 29 (2) ◽  
pp. 261-274
Author(s):  
B. Röde
Keyword(s):  
High Resolution ◽  
Proportional Counter ◽  
Rest Mass ◽  
Magnetic Spectrometer ◽  
Theoretical Expression ◽  
Energy Losses ◽  
Upper Limit

The β-spectrum of tritium has been measured with the Heidelberg (π/2)√13 high resolution magnetic spectrometer. A new almost backscatter free source technique and a special proportional counter were developed. Special attention is paid to the problem of energy losses of the electrons in the source layer to get a theoretical expression for correcting the measured spectra in a physically meaningful way. On the basis of the Wilcoxon ranktest an upper limit of 8 6 eV at 90 per cent confidence was obtained for the antineutrino rest mass.

A New Determination of the π- Rest Mass

1976 ◽  
Vol 31 (10) ◽  
pp. 1150-1154
Author(s):  
A. Brandão d'Oliveira ◽  
H. Daniel ◽  
T. von Egidy ◽  
F. J. Hartmann
Keyword(s):  
Rest Mass ◽  
X Ray ◽  
Upper Limit ◽  
Pionic Atoms

Abstract The π- rest mass has been determined from measurements of X-ray transitions in pionic atoms, using muonic transitions for the calibration, to be mπ-= 139.571 ± 0.010 MeV. A new upper limit for the μ-neutrino rest mass was deduced: mv<0.78 MeV at 90 per cent confidence.

High-resolution microscopy of twin boundaries in gold

1987 ◽  
Vol 45 ◽  
pp. 260-261
Author(s):  
William Krakow ◽  
David A. Smith
Keyword(s):  
High Resolution ◽  
Specimen Preparation ◽  
Gold Films ◽  
Boundary Area ◽  
Transmission Electron ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Microscopy ◽  
Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

High-Resolution Image Simulation of a Tilted Crystal

1990 ◽  
Vol 48 (1) ◽  
pp. 68-69
Author(s):  
C. J. D. Hetherington
Keyword(s):  
High Resolution ◽  
Crystal Thickness ◽  
Thin Specimen ◽  
Atomic Structures ◽  
Kikuchi Lines ◽  
High Resolution Images ◽  
Final Estimate ◽  
Simulated Images ◽  
Habit Planes

Most high resolution images are not directly interpretable but must be compared with simulations based on model atomic structures and appropriate imaging conditions. Typically, the only parameters that are adjusted, in addition to the structure models, are crystal thickness and microscope defocus. Small tilts of the crystal away from the exact zone axis have only rarely been considered. It is shown here that, in the analysis of an image of a silicon twin intersection, the crystal tilt could be accurately estimated and satisfactorily included in the simulations.The micrograph shown in figure 1 was taken as part of an HREM study of indentation-induced hexagonal silicon. In this instance, the intersection of two twins on different habit planes has driven the silicon into hexagonal stacking. However, in order to confirm this observation, and in order to investigate other defects in the region, it has been necessary to simulate the image taking into account the very apparent crystal tilt. The inability to orientate the specimen at the exact [110] zone was influenced by i) the buckling of the specimen caused by strains at twin intersections, ii) the absence of Kikuchi lines or a clearly visible Laue circle in the diffraction pattern of the thin specimen and iii) the avoidance of radiation damage (which had marked effects on images taken a few minutes later following attempts to realign the crystal.) The direction of the crystal tilt was estimated by observing which of the {111} planes remained close to edge-on to the beam and hence strongly imaged. Further refinement of the direction and magnitude of the tilt was done by comparing simulated images to experimental images in a through-focal series. The presence of three different orientations of the silicon lattice aided the unambiguous determination of the tilt. The final estimate of a 0.8° tilt in the 200Å thick specimen gives atomic columns a projected width of about 3Å.

Quantitative Radioisotope Measurement of Duodenogastric Reflux in Patients with Ulcer or Gastrectomized for Ulcer

1985 ◽  
Vol 24 (03) ◽  
pp. 107-110
Author(s):  
M. Pääkkönen ◽  
S. Aukee ◽  
K. Korhonen ◽  
A. Pääkkönen ◽  
E. Länsimies ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Background Activity ◽  
Bile Reflux ◽  
Duodenogastric Reflux ◽  
Upper Limit ◽  
Visual Evidence ◽  
Biochemical Measurement

SummaryIn this work the duodenogastric reflux was quantified as the amount of radioactivity entering the stomach after an i.v. administration of 99mmTc-HIDA in ulcer patients and in patients who had undergone BI gastrectomy. The results were compared with visual evidence of gastric activity in the gamma camera images and biochemical determination of gastric bile reflux. The method is useful in quantifying the reflux if the activity is above the background activity. It allows the determination of an upper limit for the reflux when the reflux is evident visually. Only two or three images are needed for the quantitation. No correlation was found between biochemical measurement of fasting bile reflux in the stomach and radioisotopic quantification.

Determination of the Activity of Pulmonary Tuberculosis: the Utility of High-Resolution Computed Tomography

2000 ◽  
Vol 42 (5) ◽  
pp. 757
Author(s):  
Myung Hee Chung ◽  
Hae Giu Lee ◽  
Won Jong Yu ◽  
Hong Jun Chung ◽  
Bo Sung Yang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Pulmonary Tuberculosis ◽  
High Resolution Computed Tomography
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