THE IEC METHOD AND CONVERSION COEFFICIENTS OF THE 605-keV TRANSITION IN 134Ba

1966 ◽  
Vol 44 (3) ◽  
pp. 549-562 ◽  
Author(s):  
E. F. Zganjar ◽  
J. H. Hamilton
Keyword(s):  
Beta Decay ◽  
Photon Energy ◽  
Conversion Coefficient ◽  
Theoretical Calculations ◽  
Accurate Determination ◽  
A Value ◽  
Conversion Coefficients ◽  
Double Focusing ◽  
Made In

Tests of the internal–external method of measuring conversion coefficients in the Vanderbilt double-focusing spectrometer have been made in search of possible errors arising from scattering of photoelectrons in the converter for a photon energy of 605 keV. This scattering may affect the factor, f, which corrects for the anisotropic distribution of the photoelectrons. The 605-keV transition in 134Ba populated by the beta decay of 134Cs was used. An accurate determination of the K, L, and M conversion coefficients of the 2+ to 0+, 605-keV, E2 transition in 134Ba was made. Three uranium converters 1.12, 2.19, and 3.71 mg/cm2 thick were used. The results are compared with the new theoretical calculations of f which depend on the converter thickness and consequently consider the effect of scattering. For photons of energy 605 keV or greater, the IEC method used in the Vanderbilt double-focusing spectrometers is insensitive (< 5%) to scattering in uranium converters < 4 mg/cm2 thick. The K, L, and M conversion coefficients were determined to be (5.03 ± 0.20) × 10−3, (7.07 ± 0.50) × 10−4, and (1.64 ± 0.18) × 10−4, respectively. The respective theoretical values of Rose are 5.08 × 10−3, 6.92 × 10−4, and 2.77 × 10−4. Sliv and Band give a value of 5.10 × 10−3 for the K conversion coefficient.

scholarly journals III. On the determination, at sea, of the specific gravity of sea-water

1875 ◽  
Vol 23 (156-163) ◽  
pp. 301-308 ◽  
Keyword(s):  
Specific Gravity ◽  
Physical Condition ◽  
Sea Water ◽  
Accurate Determination ◽  
Actual Difference ◽  
Made In

In the investigation of the physical condition of the ocean the accurate determination of the specific gravity of the water holds a first place. The tolerably numerous observations which have been made in this direction, in a more or less connected manner, are sufficient to prove that the density of the water varies, not only with the latitude and longitude, but also with the distance from the surface of the source from which it is taken. This difference of density depends partly on an actual difference in saltness, and partly on a difference in temperature of the water.

LANGEVIN DESCRIPTION OF THE EVAPORATION RESIDUE SPIN DISTRIBUTION

2008 ◽  
Vol 17 (09) ◽  
pp. 1875-1882 ◽  
Author(s):  
WEI YE ◽  
HONG-WEI YANG ◽  
FENG WU
Keyword(s):  
Theoretical Calculations ◽  
Accurate Determination ◽  
Viscosity Coefficient ◽  
Evaporation Residue ◽  
Langevin Equations ◽  
Compound System ◽  
Spin Distribution ◽  
Langevin Approach ◽  
Evaporation Residue Cross Section

The recently measured spin distribution of evaporation residue cross section in the reaction 16 O + 184 W is studied in the framework of Langevin equations. Results show that the Langevin approach can describe this observable very well. Moreover, a pre-saddle nuclear viscosity coefficient of 5 × 1021 s-1 is extracted by comparing theoretical calculations with experimental data. We also explore the effect of the isospin of a system on the spin distribution by evaluating the evaporation residue spin distribution of nuclei 194 Pb , 200 Pb and 206 Pb . It has been found that with increasing the isospin of the system, the sensitivity of the evaporation residue spin distribution to the nuclear viscosity is decreased significantly. This result suggests that choosing a low-isospin compound system favors an accurate determination of pre-saddle dissipation strength.

scholarly journals Discussion on the structure of atomic nuclei

1929 ◽  
Vol 123 (792) ◽  
pp. 373-390 ◽  
Keyword(s):  
Accurate Determination ◽  
Essential Point ◽  
Whole Numbers ◽  
Atomic Nuclei ◽  
Whole Number ◽  
Nuclear Atom ◽  
The Individual ◽  
The Masses ◽  
Made In

Sir Ernest Rutherford: It was on March 19, 1914, that the Royal Society held its last discussion on the constitution of the atom—just fifteen years ago. I had the honour to open the discussion on that occasion, and the other speakers were Mr. Moseley, Profs. Soddy, Nicholson, Hicks, Stanley Allen, S. P. Thomp­son. In my opening remarks I put forward the theory of the nuclear atom and the evidence in support of it, while Mr. Moseley gave an account of his X-ray investigations, which defined the atomic numbers of the elements, and showed how many gaps were present between hydrogen number 1 and uranium number 92. Prof. Soddy drew attention to the existence of isotopes in the radioactive series, and also to a remarkable observation by Sir Joseph Thomson and Dr. Aston, who had obtained two parabolas in the positive ray spectrograph of neon, and he suggested that possibly the ordinary elements might also consist of mixture of isotopes. I think you will find that the remarks and suggestions made in this discussion fifteen years ago have a certain pertinence to-day. In particular Hicks and Stanley Allen drew attention to the importance of taking into account the magnetic fields in the nucleus, although at that time we had very little evidence on that point, and even to-day our information is very scanty. What has been accomplished in the intervening period ? On looking back we see that three new methods of attack on this problem have been developed. The first, and in some respects the most important, has been the proof of the isotopic constitution of the ordinary elements, and the accurate determination of the masses or weights of the individual isotopes, mainly due to the work of Dr. Aston. This has led in a sense to an extension of the original ideas of Moseley. The experiments of the latter fixed the number of possible nuclear charges, while Aston has shown that there are a large number of species of atoms each defined by its nuclear charge, although their masses and their nuclear constitution may be different. The essential point brought out in the earlier work of Dr. Aston was that the masses of the elements are approxi­mately expressed by whole numbers, where oxygen is taken as 16—with the exception of hydrogen itself. But the real interest, as we now see it, is not the whole number rule itself, but rather the departures from it.

scholarly journals On a relation between the refractive and dispersive constants of the inert gases

1927 ◽  
Vol 114 (769) ◽  
pp. 659-661
Keyword(s):  
Accurate Determination ◽  
Inert Gases ◽  
Critical Temperatures ◽  
Philosophical Magazine ◽  
Empirical Relations ◽  
Five Elements ◽  
Made In

In 1911 I published in the ‘Philosophical Magazine’ a paper on new determinations of some constants of the inert gases, and drew attention to the remarkable empirical relations which subsist between (1) the calculated numbers of “dispersion” electrons in the atoms of these five elements, (2) their “viscosity diameters” as determined by Prof. A. O. Rankine, and (3) their critical temperatures. Since that time the figures used have undergone revision. The accurate determination of the value of ε by Millikan has enabled us to give absolute, instead of relative, values to the apparent numbers of dispersion electrons ( q , see Table I). Chapman has recalculated the viscosity diameters, and Rankine has revised Chapman’s values, in the light of corrections to be made in his own values of Sutherland’s constants for argon, krypton and xenon. But these alterations have not affected the validity of the relations then published.

Accurate determination of iron, copper and zinc in human serum by isotope dilution analysis using double focusing ICP-MS

1999 ◽  
Vol 14 (9) ◽  
pp. 1505-1510 ◽  
Author(s):  
Cristina Sariego Muñiz ◽  
Juan M. Marchante Gayón ◽  
J. Ignacio García Alonso ◽  
Alfredo Sanz-Medel
Keyword(s):  
Human Serum ◽  
Isotope Dilution ◽  
Accurate Determination ◽  
Isotope Dilution Analysis ◽  
Iron Copper ◽  
Copper And Zinc ◽  
Icp Ms ◽  
Double Focusing

scholarly journals Derivation of the Rotational Frequency of Massive Stars from Seismic Studies

2004 ◽  
Vol 215 ◽  
pp. 199-204 ◽  
Author(s):  
C. Aerts ◽  
R. Scuflaire ◽  
A. Thoul
Keyword(s):  
Main Sequence ◽  
High Spatial Resolution ◽  
Massive Stars ◽  
Accurate Determination ◽  
Rotation Frequency ◽  
Rotational Frequency ◽  
Current Status ◽  
B Stars ◽  
Made In

In this contribution we review the current status of the determination of the rotational frequency in non-radially pulsating B stars, i.e. β Cep stars and slowly pulsating B stars. Considerable progress is currently being made in the understanding of the non-radial oscillations of main-sequence B stars by means of high-temporal, high-spatial resolution spectroscopic time series. This has led to the detection of frequency multiplets, which are interpreted as rotationally splitted non-radial modes and which allow an accurate determination of the surface rotational frequency in some stars. We outline how our future goal, i.e. the derivation of the internal rotation frequency, can be achieved.

THE TOTAL INTERNAL CONVERSION COEFFICIENT OF THE 279-kev TRANSITION FOLLOWING THE DECAY OF Hg203 AS MEASURED BY A NEW COINCIDENCE METHOD

1962 ◽  
Vol 40 (4) ◽  
pp. 383-392 ◽  
Author(s):  
J. G. V. Taylor
Keyword(s):  
Standard Deviation ◽  
Internal Conversion ◽  
Conversion Coefficient ◽  
Internal Conversion Coefficient ◽  
Coincidence Method ◽  
Β Decay ◽  
A Value ◽  
Conversion Coefficients ◽  
Γ Ray ◽  
Total Conversion Coefficient

Using a new coincidence method, the total internal conversion coefficient for the 279-kev transition following the β-decay of Hg203 has been measured with a standard deviation of about 1%. The method which employs a 4πβ–γ coincidence arrangement is based on the differential absorption of β-particles and conversion electrons in 4π geometry. For determining the absolute efficiencies of γ-ray spectrometers or ion-chambers, the method has the advantage of yielding directly the number of γ-ray quanta emitted per Hg203 disintegration without requiring any knowledge of the K:L:M conversion ratios. Likely sources of systematic error have been investigated and their effect has been shown to be smaller than the quoted standard deviation. The value obtained is α = 0.2262 ±.0019 or γ/β = 0.8155 ±.0015, in excellent agreement with the recent β-ray spectrometer measurements of Nijgh et al. This is of interest because a number of widely differing values of conversion coefficients for this transition have been reported. If the K/(L+M+N) conversion ratio of 2.60 ±.06 found by Nijgh et al. is combined with our total conversion coefficient, a value αK = 0.1633 ±.0017 is obtained.

Optical properties of cubic AlGaN

2001 ◽  
Vol 693 ◽  
Author(s):  
Stéphane Fanget ◽  
Catherine Bru-Chevallier ◽  
Gérard Guillot ◽  
Esteban Martinez-Guerrero ◽  
Denis Jalabert ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Accurate Determination ◽  
Excitation Power ◽  
Multilayered Structure ◽  
Interface Roughness ◽  
Aluminum Concentration ◽  
Reflectivity Spectra ◽  
Dependence Versus ◽  
Power Evolution

AbstractIn this work we report optical characterization on several cubic c-AlGaN layers grown by MBE on SiC on Si pseudo-substrates, with different aluminum concentrations ranging from 0 to 70 %. Excitation power evolution of AlGaN photoluminescence (PL) spectra as well as reflectivity spectra allow to attribute PL peak to band gap recombination. PL energy dependence versus aluminum concentration is given. Reflectivity investigations are performed in the energy range between 1.5 eV and 4 eV on the samples. Theoretical calculations of multilayered structure reflectivity are fitted to experimental results, allowing an accurate determination of refractive index evolution versus Al concentration. From this analysis, qualitative information about interface roughness at AlGaN/SiC is also be derived.

K-Conversion Coefficients of Transitions in In114 and Cd114

1967 ◽  
Vol 22 (3) ◽  
pp. 309-316
Author(s):  
M. S. El-Nesr ◽  
Z. Awwad ◽  
M. R. El-Aassar
Keyword(s):  
High Resolution ◽  
Excellent Agreement ◽  
Conversion Coefficient ◽  
Electric Quadrupole ◽  
Isomeric Transition ◽  
Conversion Method ◽  
Conversion Coefficients ◽  
Double Focusing ◽  
First Time ◽  
Good Agreement

The K-conversion coefficients of the 192 keV isomeric transition in In114 and the 556 and 722 keV transitions in Cd114 have been measured for the first time by means of a high resolution double focusing β-ray spectrometer, using the internal-external conversion method. The results obtained are:αk (192 keV-In114) = 2.3653 ± 0.3075,in excellent agreement with the theoretical value 2.4638 for pure E4 transition calculated by SLIV and BAND, andαK (556 keV-Cd114) = 0.00419 ± 0.00046,αK (722 keV - Cd114) = 0.00207 ± 0.00025,both results in excellent agreement with the theoretical values for pure electric quadrupole radiation 0.00432 and 0.00218 respectively computed by SLIV and BAND. These data confirm the essentially pure E4 character of the 5 + → 1 +, 192 keV transition in In114 and the pure E2 character of the 4 + → 2 +, 722 keV and 2 + → 0 +, 556 keV transitions in Cd114. The conversion coefficient measurements reported here in Cd114 and In114 (Z=48 and 49) and in earlier studies (Z=22 - 28 and 56) indicate that E2-conversion coefficients in the Z region below 60 are in good agreement with theory.

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