The total energy of the γ-radiation emitted from the active deposit of actinium

1938 ◽  
Vol 34 (3) ◽  
pp. 429-434 ◽  
Author(s):  
E. Kara-Michailova
Keyword(s):  
Fine Structure ◽  
Absorption Coefficient ◽  
Total Energy ◽  
Excellent Agreement ◽  
Experimental Error ◽  
Γ Radiation ◽  
Γ Rays ◽  
Γ Ray ◽  
Good Agreement ◽  
Α Particles

The disintegrations by which Ac B passes into the inactive AcPb are accompanied by a γ-radiation very weak compared with the intense γ-emission in the case of Ra or Th-active deposit. The analysis of the secondary β-ray spectrum of actinium-active deposit has revealed the existence of at least five γ-rays (1) (see Table I), of which the ray with energy 0·349 × 106 e.V. definitely belongs to the disintegration Ac C—C″ and is associated with the fine-structure of α-particles of Ac C. According to the measurements of Surugue the two rays of 0·4038 × 106 and 0·4257 × 106 e.V. energy are to be attributed to the disintegration AcB—C, whereas the origin of the 0·829 × 106 e.V. ray is less definite. The fit with experiments is best if this ray is assumed to be emitted from Ac B—C; but it may also (within experimental error) be attributed to the disintegration Ac C″—Pb. Experiments on the absorption coefficient of the γ-radiation of RaAc and its disintegration products prove that the 0·829 × 106 e.V. ray is the hardest γ-ray emitted by the active deposit of actinium(2). The value for the absorption coefficient between 4·6 and 10·6 cm. of lead was found to be μ/ρ = 0·76, in good agreement with the value found in previous experiments at smaller absorptions in aluminium (3). There is, on the whole, excellent agreement concerning the energies of the γ-components as measured according to different methods by different observers.

The interval between the departure of the disintegration particle and the emission of the gamma radiation

1932 ◽  
Vol 28 (1) ◽  
pp. 128-135 ◽  
Author(s):  
P. Wright
Keyword(s):  
Gamma Radiation ◽  
Γ Radiation ◽  
Γ Rays ◽  
Γ Ray ◽  
Recoil Atoms ◽  
Rough Calculation ◽  
Α Particles

Previous work on the existence and period of radium C′ is discussed with reference to an experiment of Jacobsen which provides evidence that a γ ray transformation of period comparable with that of radium C′ precedes the expulsion of α particles. It is shown that, from Jacobsen's results, part of the γ radiation from a source of recoil atoms should originate in the space surrounding the source.A rough calculation is made which shows that the γ rays above the source should be detectable by ordinary methods, and a description is given of an ionisation method capable of detecting the effect. The γ rays predicted by Jacobsen's experiment were tested for by using specially prepared sources of radium C. Phenomena associated with α recoil were also investigated for sources of radium (B + C) and thorium (B + C).No evidence of a γ ray emission from the space above any of the sources was obtained. The negative result indicates that the interval between the departure of the disintegration particle and the emission of the γ ray quantum is considerably less than 10−5second.

ON THE γ-RAY SPECTRUM OF Ra(B + C)

1952 ◽  
Vol 30 (5) ◽  
pp. 442-449 ◽  
Author(s):  
G. N. Whyte
Keyword(s):  
Recent Information ◽  
Γ Rays ◽  
Γ Ray ◽  
Good Agreement

Measurements of the transmission of Ra(B + C) γ rays through lead between 0 and 26 cm. are described and compared with the transmissions predicted on the basis of a modified version of the γ-ray spectrum of Ellis and Aston and on the basis of the spectrum of Latyshev et al. Ellis and Aston's spectrum gives the better agreement. Both the relative and absolute values of the γ-ray intensities given by Ellis and Aston are revised in the light of more recent information. This revised spectrum leads to a predicted value of 0.84 roentgens per hour at a meter for the γ-ray output of a gram of radium and its equilibrium products in 0.5 mm. of platinum, in good agreement with experiment.

Decay of 143Eu

1974 ◽  
Vol 52 (10) ◽  
pp. 847-853 ◽  
Author(s):  
G. Kennedy ◽  
S. C. Gujrathi ◽  
P. F. Hinrichsen
Keyword(s):  
Ground State ◽  
Coupling Model ◽  
Intermediate Coupling ◽  
Ground State Spin ◽  
Reaction Data ◽  
Intermediate Coupling Model ◽  
Γ Rays ◽  
Γ Ray ◽  
State Spin ◽  
Good Agreement

A high resolution study of γ-ray transitions in 143Sm following the β+ decay of 143Eu has been made using Ge(Li) detectors. Fifty-seven γ rays are assigned to the decay of 143Eu, and the ground state spin of 143Eu is established as 5/2+. Spin and parity assignments are made on the basis of γ-ray branching, deduced log ft values, and by comparison with previous (p,d) reaction data. Good agreement between experiment and predictions of the intermediate coupling model suggests that this model adequately accounts for the low lying levels of 143Sm.

scholarly journals A search for high-energy γ-rays from pulsars

1970 ◽  
Vol 37 ◽  
pp. 192-195 ◽  
Author(s):  
G. G. Fazio ◽  
D. R. Hearn ◽  
H. F. Helmken ◽  
G. H. Rieke ◽  
T. C. Weekes
Keyword(s):  
Energy Region ◽  
Energetic Particle ◽  
Crab Nebula ◽  
High Energy ◽  
Γ Radiation ◽  
Γ Rays ◽  
Γ Ray ◽  
Cerenkov Light

The 10-m optical reflector at Mt. Hopkins, Ariz., was used to search for cosmic γ radiation from pulsars by detection of atmospheric Čerenkov light generated by energetic particle showers. In the energy region of 1011–1012 eV, no evidence of pulsed γ-ray emission was found from either NP0532 (Crab Nebula) or CP1133.

A HIGH RESOLUTION FLAT CRYSTAL SPECTROMETER FOR NEUTRON CAPTURE γ-RAY STUDIES

1959 ◽  
Vol 37 (2) ◽  
pp. 203-231 ◽  
Author(s):  
J. W. Knowles
Keyword(s):  
Single Crystal ◽  
Neutron Capture ◽  
Counting Efficiency ◽  
Double Crystal ◽  
Γ Rays ◽  
Γ Ray ◽  
Antiparallel Position ◽  
Crystal Arrangement ◽  
Good Agreement ◽  
Soller Slit

A flat crystal diffraction spectrometer, constructed for the measurement of γ-rays resulting from neutron capture, is discussed both experimentally and theoretically. The spectrometer is used either as a single crystal or a double crystal instrument. In the single crystal arrangement a Laue diffracted γ-ray beam from a broad source proceeds through a Soller slit which gives it a 45-second angular divergence, to a sodium iodide scintillation detector. The energy is determined by the angle between the Soller slit and the crystal. The resolution is determined by the Soller slit, and is 4% at 1 Mev when diffracting from the (440) planes of a single germanium crystal. In the two-crystal configuration a γ-ray which is Laue diffracted from the first crystal is further diffracted from a second crystal set in the antiparallel position. The angle between the reflecting planes of the two crystals determines the γ-ray energy. The Soller slit serves only as shielding for the detector in this arrangement. The resolution depends upon the mosaics and thicknesses of the crystals; it is 0.4% at 1 Mev for diffraction from the (211) planes of two calcite crystals, each 23 mm thick and of 1.7- and 0.9-second mosaics respectively. The range of measurement extends from 80 kev to greater than 5 Mev. Where other values of γ-ray energies exist, agreement to within the expected precision, ± 0.2% is obtained. The counting efficiency as a function of energy depends on the integrated reflectivities of the crystals which may be determined at the time of a γ-ray measurement by means of the double crystal arrangement. The integrated reflectivity as a function of energy has been calculated for a number of crystals of known mosaic and throughout the range of measurement, from 0.2 to 5 Mev, good agreement is obtained.

scholarly journals Some experiments concerning the counting of scintillations produced by alpha particles.— Part I

1929 ◽  
Vol 122 (789) ◽  
pp. 304-319 ◽  
Keyword(s):  
Experimental Method ◽  
Atomic Structure ◽  
Alpha Particles ◽  
Γ Radiation ◽  
Modern Conception ◽  
Scintillation Method ◽  
Γ Rays ◽  
Α Particles

Among the various methods of detecting single a-particles, the scintillation method, because of its simplicity, is often the only one applicable. When the particles are to be counted in the presence of a strong β and γ radiation, the scintillation method is indispensable, for the scintillations produced by α-particles are easily detectable on the luminous background produced by the β and γ rays, while the electrical counter is seriously disturbed by these types of radiation. Though the counting of scintillations has been constantly used as an experimental method since 1908, and practically all the fundamental data on which the modern conception of atomic structure is based, were obtained by this method, very little systematic work has been done concerning the method itself and its limitations.

scholarly journals An analysis of the fine structure of the α-particle groups from thorium C and of the long range groups from thorium C′

1934 ◽  
Vol 145 (854) ◽  
pp. 235-249 ◽  
Keyword(s):  
Fine Structure ◽  
Excellent Agreement ◽  
Energy Levels ◽  
Accurate Determination ◽  
Energy Difference ◽  
Spectrum Measurement ◽  
Method Of Measurement ◽  
Γ Ray ◽  
Electronic Field

During the course of our previous measurements of the fine structure of α-particle groups we obtained preliminary measurements of the fine structure of the α-particle groups from thorium C. The results were in general agreement with those previously obtained by Rosenblum and Valadares, who photographed the α-ray spectrum. Our method of measurement appeared capable of yielding results of accuracy as high as 1 in 100,000 in velocity. Accordingly a series of measurements has now been carried out to examine the thorium C groups with much greater precision, and these experiments are described in the present paper. Our results provide information, which we believe to be of considerable accuracy, concerning the energy levels of the thorium C nucleus. When interpreted by Gamow's theory these measurements are in excellent agreement with certain γ-ray energies deduced from entirely independent β-ray measurements. By accelerating the particles in an electronic field we have in addition been able to measure the energy difference between the two most prominent groups of α-particles from thorium C, by a direct electrostatic measurement. This independent measurement is probably the most accurate determination of this energy difference, and is in excellent agreement with the energy of a strong γ-ray deduced from the β-ray spectrum measurement by Ellis.

The number of α-particles emitted by thorium C + C′

1928 ◽  
Vol 24 (1) ◽  
pp. 133-138 ◽  
Author(s):  
S. W. Watson ◽  
M. C. Henderson
Keyword(s):  
Γ Rays ◽  
Γ Ray ◽  
Α Particles

The number of α-particles emitted per second by thorium (C + C′) has been determined by an ionisation method. The number obtained is 4·26 ± ·08 × 1010 α-particles per second per curie equivalent γ-ray activity when in equilibrium with radio-thorium and when measured by the γ-rays of thorium C″ through 18 mm of lead. The result agrees within 1 per cent, with that extrapolated from Shenstone and Schlundt's values.The same apparatus was used to determine the slope of the Bragg curve over the first three centimetres of the range. The data fit the curve as given by I. Curie and Behounek within the accuracy of experiment. The curve given by G. H. Henderson falls too rapidly as it approaches the axis of ordinates.

A GAMMA RAY IONIZATION CHAMBER

1932 ◽  
Vol 7 (1) ◽  
pp. 103-105 ◽  
Author(s):  
George C. Laurence
Keyword(s):  
Absorption Coefficient ◽  
Ionization Chamber ◽  
Gamma Ray ◽  
Precision Measurements ◽  
Γ Rays ◽  
Γ Ray

A description is given of a γ-ray ionization chamber with its accessory electrometer box, suitable for precision measurements of radioactive preparations, and for the measurement of the absorption coefficient and specific ionizing powers in air, of γ-rays.

scholarly journals The association of γ-rays with the α-particle groups of thorium C

1932 ◽  
Vol 136 (829) ◽  
pp. 396-406 ◽  
Keyword(s):  
Long Range ◽  
Direct Evidence ◽  
Transition Probabilities ◽  
Essential Difference ◽  
Γ Radiation ◽  
Γ Rays ◽  
The One ◽  
Alternative Processes ◽  
Particle Group ◽  
Α Particles

As a result of the experiments of Rutherford, Ward and Lewis, it is now generally accepted that the emission of γ-rays from radioactive bodies is associated with the transitions of α-particles between stationary states in the nucleus. Direct evidence for the existence of these excited states in the case of radium C' is obtained from the several groups of long range α-particles which have been detected. Rosenblum has found that thorium C also emits several groups of α-particles, and the existence of a corresponding number of nuclear α-particle states can be safely inferred, which should also give rise to γ-radiation. This case was first discussed by Gamow, who pointed out that there was an essential difference here from radium C' In the latter body the extra α-particle states all have energy greater than the normal, and emission of the corresponding long range α-particles is a rare phenomenon, of the order of one long range particle for a million normal α-particles. The case of radium C' appears to be accounted for satisfactorily by the assumption of two alternative processes, either internal nuclear switch or α-emission from the excited state, the relative frequencies of occurrence depending on the ratio of the transition probabilities. With thorium C, however, the most intense α-particle group is not the one of lowest energy, and the groups only vary in intensity by a factor of one hundred instead of one million as with radium C' The assumption of alternative processes of γ-and α-emission would lead to values for the ratio of the transition probabilities for the two processes which are absolutely incompatible with what is known about the orders of magnitude of the probabilities of α-particle emission and radiation switch. Gamow therefore proposed that the thorium C nucleus is initially formed with its α-particles all in the gromid state and that disintegration could sometimes occur in such a way as to leave the product nucleus excited. Rosenblum gives the following data for the velocities and relative intensities of the groups from thorium C.

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