scholarly journals An upper limit on the spontaneous fission decay constant of232Th derived from xenon in monazites with extremely high Th/U ratios

1999 ◽  
Vol 26 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Rainer Wieler ◽  
Jost Eikenberg
Keyword(s):  
Spontaneous Fission ◽  
Decay Constant ◽  
Upper Limit

THE YIELDS OF 129I IN NATURAL AND IN NEUTRON-INDUCED FISSION OF URANIUM

1956 ◽  
Vol 34 (3) ◽  
pp. 293-300 ◽  
Author(s):  
B. C. Purkayastha ◽  
G. R. Martin
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Spontaneous Fission ◽  
Capture Cross Section ◽  
Neutron Capture Cross Section ◽  
Fission Yield ◽  
Natural Production ◽  
Upper Limit ◽  
Induced Fission ◽  
Spectrometric Measurements

Measurements have been made, by a radioactivation technique, of the 129I formed in uranium by pile-neutron-induced fission, and in pitchblende by the natural fission of uranium. The amount found in the pile-neutron-irradiated uranium corresponds to a fission yield of 0.90% at mass 129. The natural production of 129I in pitchblende is discussed in the light of the mass-spectrometric measurements of spontaneous fission xenon made by Thode and his collaborators. An upper limit of 1 part in 108 can be set for the occurrence of 129I in natural iodine. The pile neutron capture cross section of 129I has been measured as 35 barns.

Spontaneous-Fission Decay Constant ofU238

1968 ◽  
Vol 174 (4) ◽  
pp. 1482-1484 ◽  
Author(s):  
J. H. Roberts ◽  
Raymond Gold ◽  
Roland J. Armani
Keyword(s):  
Spontaneous Fission ◽  
Decay Constant

Decay constant for the spontaneous-fission process in 238U

1982 ◽  
Vol 197 (2-3) ◽  
pp. 417-426 ◽  
Author(s):  
H.G. De Carvalho ◽  
J.B. Martins ◽  
E.L. Medeiros ◽  
O.A.P. Tavares
Keyword(s):  
Spontaneous Fission ◽  
Decay Constant ◽  
Fission Process

scholarly journals On the nuclear forces and the magnetic moments of the neutron and the proton

1938 ◽  
Vol 166 (924) ◽  
pp. 154-177 ◽  
Keyword(s):  
Cosmic Radiation ◽  
Decay Constant ◽  
Magnetic Moments ◽  
Cosmic Ray ◽  
Exchange Theory ◽  
Approximate Theory ◽  
Nuclear Forces ◽  
Hard Component ◽  
Heavy Particles ◽  
Upper Limit

It was first suggested by Heisenberg that the forces between a proton and a neutron are connected with an exchange of charge between the two heavy particles. This exchange nature of the neutron-proton forces is now generally accepted. It would follow from this assumption that in suitable circumstances a proton (neutron) could emit a positively (negatively) charged particle transforming itself into a neutron (proton). At first sight it seemed that the emission of positive or negative electrons in the β -decay could in this way be made responsible for the nuclear forces. This was, in fact, suggested by Iwanenko (1934) and Tamm (1934). It has also been pointed out by Wick (1935) that the virtual emission of β -electrons might explain the values of the magnetic moments of the proton and the neutron. These theories, however, were not successful. The nuclear forces, for instance, turn out to be too small by a factor of more than 10 10 and have far too small a range; this is due to the fact that the β -decay constant is extremely small. Since the β -decay is a process which, in nuclear dimensions, takes “geological ages”, one might think that the ordinary properties of the heavy particles have no direct connexion with this process and that an approximate theory of the nuclear forces should be possible without the inclusion of the β -decay. A new hope for such an “exchange theory” of the properties of nuclei is offered by the probable existence of a hitherto unknown type of particle constituting the hard component of cosmic radiation. Since these particles do not lose much energy by radiation, it has been suggested by Neddermeyer and Anderson (1937) that they are (positive and negative) “heavy electrons” with a mass between that of an electron and a proton. From cosmic-ray data the mass of these particles can hardly be determined yet, but it can be limited to values between 3 and 300 electron masses. There are, however, some arguments favouring a mass nearer to the upper limit of 100-200 electron masses.

Search for the decayD+→μ+νμand an upper limit on the pseudoscalar decay constant

1988 ◽  
Vol 60 (14) ◽  
pp. 1375-1378 ◽  
Author(s):  
J. Adler ◽  
J. J. Becker ◽  
G. T. Blaylock ◽  
T. Bolton ◽  
J. S. Brown ◽  
...  
Keyword(s):  
Decay Constant ◽  
Upper Limit ◽  
Pseudoscalar Decay Constant

ON THE SUPERSTRING AXION MINI-STAR

1998 ◽  
Vol 13 (13) ◽  
pp. 1007-1017 ◽  
Author(s):  
M. D. POLLOCK
Keyword(s):  
Gravitational Collapse ◽  
Mass Formula ◽  
Decay Constant ◽  
Gravitational Constant ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Planck Mass ◽  
Upper Limit ◽  
Axion Decay Constant ◽  
Axion Decay

The theory of the pressure-free-boson mini-star of mass M, whose radius r=2GM/v2 is equated via the indeterminacy principle to ℏ/mv, where [Formula: see text] is the Newton gravitational constant, M P being the Planck mass and m the mass of the boson, travelling at velocity v, is applied to the superstring axion. For a bounded object, the upper limit to the axion potential [Formula: see text] constrains the axions to move at non-relativistic velocities [Formula: see text] where [Formula: see text] GeV is the axion decay constant, predicting the existence of an axion mini-star of mass [Formula: see text]. Such objects can in principle form by gravitational collapse below the temperature T≈100 eV, and are tentatively identified with the microlensing objects recently detected in our Galaxy and in the direction of the Large Magellanic Cloud.

Search for the DecayD+→μ+νμand an Upper Limit on the Pseudoscalar Decay Constant

1989 ◽  
Vol 63 (15) ◽  
pp. 1658-1658 ◽  
Author(s):  
J. Adler ◽  
J. J. Becker ◽  
G. T. Blaylock ◽  
T. Bolton ◽  
J. S. Brown ◽  
...  
Keyword(s):  
Decay Constant ◽  
Upper Limit ◽  
Pseudoscalar Decay Constant

Decay Constant for Spontaneous Fission ofU238

1964 ◽  
Vol 133 (1B) ◽  
pp. B63-B64 ◽  
Author(s):  
R. L. Fleischer ◽  
P. B. Price
Keyword(s):  
Spontaneous Fission ◽  
Decay Constant
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