Average Energy of Beta-Rays Emitted by Radioactive Isotopes

Marinelli, L. D.; Brinckerhoff, R. F.; Hine, Gerald J.

doi:10.1103/revmodphys.19.25

Cited by 38 publications

(4 citation statements)

References 6 publications

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“…I N the course of some work on the radioactivity of potassium, so far only partly published 1 owing to war conditions, we found a gamma-ray intensity several times larger than that published by Gray and Tarrant. 2 On ac-count of the geophysical significance of this question 3 we feel that a preliminary account of our results may be of interest. 4 The number of counts of a Geiger-Mtiller counter, first surrounded by pure K2SO4 salt disposed as a cylinder of 4.9-cm inner diameter and of 1.45-cm thickness, was compared with that given by a cylinder of cleveite of 5.75-cm inner diameter and of 0.21-cm thickness.…”

mentioning

confidence: 86%

On the Gamma-Rays ofK40

Gleditsch

Gráf

1947

Phys. Rev.

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confidence: 86%

On the Gamma-Rays ofK40

Gleditsch

Gráf

1947

Phys. Rev.

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“…Even if our smaller values are confirmed by further work on the radioactive properties of K 40 , the heat production by radioactive decay 2X10 9 years ago would have been due mainly to K 40 , which would then have exceeded the heat production by uranium and thorium 16,19 in all classes of igneous rocks. From the standpoint of the general theory of forbidden 0-ray transformations, it was thought 20 some years ago that accurate knowledge of the 0-ray energy and the half-period of K 40 would be crucial in deciding between the tensor and polar vector interactions, because it is known 21 that the nuclear angular momentum of K 40 is 4, while that of Ca 40 is probably zero.…”

Section: Discussionmentioning

confidence: 63%

“…This estimate of the heat output should replace the early value of 5X10" 6 cal./yr. g by Evans and Goodman, 16 which was based on Miihlhoff's decay constant, Anderson and Neddermeyer's 17 0-ray energy, and Gray and Tarrant's 18 gammaray emission, all three of which were too low in the light of more recent measurements. This revised heat output also replaces Gleditch and Graf's value of 38X10"" 6 cal./yr.…”

Section: Discussionmentioning

confidence: 93%

The Radioactive Decay Constants ofK40as Determined from the Accumulation ofCa40
Ahrens
¹
,
Evans
²

1948
Phys. Rev.
39
0
4
0
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New measurements of the rate of emission of gamma-ray energy by K 40 give 4.9±0.1 Mev/sec. g K, in agreement with Gleditsch and Graf. Thus the minimum value of the probability of electron capture in K 40 is X e = 0.062 XlO" 9 yr. _l . Spectrochemical analysis of 4 samples of lepidolite known to be 2.1 X10 9 years old, as well as 22 younger lepidolites, gives a maximum value of 22, and a most probable value of 11 for the ratio of radiogenic Ca 40 to residual K 40 in the 2.1 X10 9 year old minerals. In such an ancient mineral, the Ca^/K 40 ratio is a function not only of the probability of /3-ray decay, Xp, of K 40 into Ca 40 , but also the probability of transformation by electron capture, X«, of K 40 into A 40 . This is because the electron capture process may significantly deplete the K 40 , thus tending to produce larger Ca^/K 40 ratios than would result from i8-decay alone. The decay constants X# and X e reported by Bleuler and Gabriel predict Ca 40 /K 40 = 152, while Miihlhoff's X^ predicts Ca*/K*=1.48 for a 2.1 XlO 9 year old mineral. We have therefore suggested approximate corrections for the effects of /3-ray scattering in the observations by Miihlhoff and by Bleuler and Gabriel on the absolute rate of emission of j3-rays by K. These corrections lead to a mean value of 34 /3-rays/sec. g K, or X0= (0.65d=0.1)Xl0~9 yr.~l. The observed value of C*/K« = 11 then leads to X tf =(0.9±0.1)Xl0~9 yr.~\ and a total half-period of T~ (0.45±0.05)X10 9 yr. for K 40 . Then approximately 42 percent of the disintegrations of K 40 are by 0-ray emission to the ground state of Ca 40 ; 4 percent by electron capture to a 1.5-Mev excited state in A 40 , and 54 percent by electron capture to the ground state of A 40 . It is shown that these revised disintegration constants lead to a sufficiently smaller thermal output by K early in the earth's history to satisfy Birch's calculations on the possibility of an early solid terrestrial crust, and to remove arguments relating to the origin of species through gene mutations caused by intense K 40 radiations early in the earth's history.

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“…The next group loses photons in proportion to pl(E2') but gains photons from group 1 by Compton scattering; group 3 receives photons from both groups 1 and 2; and so on. The transfer of photons between groups is a function of the energy-widths of the groups and their separation in energy and is computed from the Klein-Nishina relation [Equation (14)]. The differential equations expressing the photon "economy" for each group are integrated successively, giving the flux a t r .…”

Section: F(e' R' + R)mentioning

confidence: 99%

Estimation of heat sources in nuclear reactors

Alexander

1956

AIChE Journal

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Knowledge of local heating rates is needed for estimation of operating temperatures, thermal stresses, and cooling requirements in nuclear reactor components. Heat is liberated by the dissipation of the energy of fission fragments, beta particles, fast neutrons, and gamma photons. Heating rates are formulated in terms of either neutron or gamma flux densities, the corresponding collision probabilities, and appropriate energy transfer coeficients, the forms of which are given. Special methods of estimating the flux densities are discussed. The data on the magnitudes of the various energy sources are reviewed.The designer of nuclear reactors needs to know the local rates of heat liberation in the various reactor components in order to estimate temperatures, cooling requirements, thermal stresses, corrosion rates, radiationdamage annealing rates, and temperature-dependent reactivity changes. The heat-liberation rates can be formulated in terms of the local neutron and gamma fluxes, +, , and 9, . Admittedly, isotope N'. The nucleus is "knocked on," Vol. 2, No. 2 A.1.Ch.E. Journal Page 177 Jo(2.405plR) cos ( r~/ 2 R ) 3.87 cos ( r z / A ) cos ( * y / A ) cos ( r z / A )

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Average Energy of Beta-Rays Emitted by Radioactive Isotopes

Cited by 38 publications

References 6 publications

On the Gamma-Rays ofK40

On the Gamma-Rays ofK40

The Radioactive Decay Constants ofK40as Determined from the Accumulation ofCa40
Ahrens
¹
,
Evans
²

1948
Phys. Rev.
39
0
4
0
View full text Add to dashboard Cite

Estimation of heat sources in nuclear reactors

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Average Energy of Beta-Rays Emitted by Radioactive Isotopes

Cited by 38 publications

References 6 publications

On the Gamma-Rays ofK40

On the Gamma-Rays ofK40

The Radioactive Decay Constants ofK40as Determined from the Accumulation ofCa40Ahrens1, Evans2 1948Phys. Rev.39040View full textAdd to dashboardCite

Estimation of heat sources in nuclear reactors

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The Radioactive Decay Constants ofK40as Determined from the Accumulation ofCa40
Ahrens
¹
,
Evans
²

1948
Phys. Rev.
39
0
4
0
View full text Add to dashboard Cite