24.—The Origin of the Short-range Alpha Particles of Fission

1974 ◽  
Vol 71 (4) ◽  
pp. 285-292
Author(s):  
N. Feather
Keyword(s):  
Short Range ◽  
Mass Number ◽  
Neutron Emission ◽  
Neutron Number ◽  
Alpha Particles ◽  
Similar Process ◽  
Detailed Calculation ◽  
Γ Rays ◽  
Α Particles

SynopsisThe suggestion is made, and rendered plausible by detailed calculation, that the short-range α-particles of fission, identified by Kugler and Clarke [1], are emitted, in competition with ‘prompt’ γ-rays, from highly excited post-neutron-emission fragments of even neutron number N and, predominantly, of mass number A in the range 140 ≦ A ≧ 145. A similar process is energetically forbidden in relation to triton emission.

29.—Fine-structure in the Mass-yield Curve for Binary Fission—A Possible Secondary Effect

1974 ◽  
Vol 71 (4) ◽  
pp. 333-336
Author(s):  
N. Feather
Keyword(s):  
Fine Structure ◽  
Short Range ◽  
Mass Number ◽  
Yield Curve ◽  
Neutron Emission ◽  
Secondary Effect ◽  
Mass Yield ◽  
Yield Curves ◽  
Number Range ◽  
Α Particles

SynopsisThe recent suggestion (Feather 1974) that the short-range α-particles of fission are emitted predominantly from post-neutron-emission fragments in the mass-number range 140 to 145 is shown to have implications in relation to the fine-structure of the mass-yield curve. An examination of the mass-yield curves of Unik et al. (1973) discloses, in many of them, a fine-structure feature of the type predicted.

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.

Erratum: Short Range Alpha-Particles from Fluorine and Lithium Bombarded by Protons

1950 ◽  
Vol 77 (2) ◽  
pp. 287-287 ◽  
Author(s):  
W. E. Burcham ◽  
Joan M. Freeman
Keyword(s):  
Short Range ◽  
Alpha Particles

scholarly journals Evaluation the Safety and Security Procedures used In X-ray Clinics in Al-Harthiya-Baghdad

2021 ◽  
Vol 2114 (1) ◽  
pp. 012009
Author(s):  
Thuraya A. Abdul Hussian ◽  
Anwar kh. Farman
Keyword(s):  
Ionizing Radiation ◽  
X Rays ◽  
X Ray ◽  
Beta Particles ◽  
Medical Clinics ◽  
Γ Rays ◽  
Health Laws ◽  
Different Sources ◽  
Α Particles ◽  
Security Procedures

Abstract Radiation is a form of energy, its emitted either in the form of particles such as α-particles and β-particles (beta particles including the electron and the positron) or waves such as sunlight, X-rays and γ-rays. Radiation found everywhere around us and it comes from many different sources naturally or man-made sources. In this study a questionnaire was distributed to people working in the field of X-rays that used for a medical imaging (X-ray and CT-scan) to evaluate the extent of awareness and knowledge in estimate the damage of ionizing radiation as a result of wrong use. The questionnaire was distributed to medical clinics in Al-Harithiya in Baghdad, which it’s considered as one of the important areas in Iraq to attract and treat patients. It’s found that most of the commitment of radiography clinics by safety and security procedures. Most of the radiology clinics abide by most of the Iraqi Ministry of Health laws. However, some clinics did not implement some of the security and safety conditions

ABSOLUTE STANDARDIZATION OF RADIOACTIVE NEUTRON SOURCES: II. THE USE OF THE F19(α, n)Na22 REACTION

1959 ◽  
Vol 37 (5) ◽  
pp. 550-556 ◽  
Author(s):  
K. W. Geiger
Keyword(s):  
Nuclear Reactions ◽  
Emission Rate ◽  
Neutron Emission ◽  
National Research Council ◽  
Neutron Output ◽  
Neutron Sources ◽  
Neutron Thermalization ◽  
Γ Rays ◽  
Absolute Standardization ◽  
Good Agreement

Fluorine has only one stable isotope, F19. If neutrons are produced by the F19(α, n)Na22 reaction the neutron output can be calculated from the yield of the resulting radioactive Na22. The growth of Na22 (half-life, 2.58 years) has been measured in a neutron source consisting originally of 1.6 curies Po210 mixed with CaF2 powder. Since Na22 is a positron emitter, discrimination against γ-rays from Po210 and from nuclear reactions could be achieved by detecting the two positron annihilation quanta in coincidence. The Na22 growth has been followed over 20 months and is in agreement with the theoretical growth curve. Comparison with a calibrated Na22 source yielded a neutron emission rate of (10.70 ± 0.25) × 104 sec−1. This resulted in a neutron emission rate of (3.16 ± 0.10) × 106 sec−1 for the Ra-α-Be source of the National Research Council, in good agreement with (3.22 ± 0.05) × 106 sec−1 obtained by a neutron thermalization method.

scholarly journals The nuclear photoelectric effect

1935 ◽  
Vol 151 (873) ◽  
pp. 479-493 ◽  
Author(s):  
James Chadwick ◽  
M. Goldhaber
Keyword(s):  
Heavy Particle ◽  
Photoelectric Effect ◽  
Necessary Condition ◽  
Mass Defect ◽  
Radioactive Elements ◽  
Negative Mass ◽  
Photo Effect ◽  
Sufficient Intensity ◽  
Γ Rays ◽  
Α Particles

Some time ago we reported in ‘Nature’ the observation of a nuclear photo-effect, the disintegration of the deutron by γ-rays. An effect of y-rays upon complex nuclei might be expected to occur from analogy with the phenomena of excitation and ionization of atoms by light, and such an effect has been looked for from time to time by various investigators. A necessary condition to make disintegration possible is that the energy of the γ-ray quantum must be greater than the binding energy of the particle which is to be removed from the nucleus. The most energetic γ-rays which are readily available in sufficient intensity are those of thorium C", which have an energy hv — 2·62 x 10 6 electron volts. One can hope, therefore, using these γ-rays, to produce disintegration with the emission of a heavy particle, such as a neutron, proton, etc., only in those nuclei which have a small or negative mass defect, such as the nuclei of deuterium, beryllium, and those radioactive elements which emit α-particles. In fact, only the nuclei of deuterium and beryllium have so far been disintegrated in this way. The disintegration of beryllium by the γ-rays of radium was first reported by Szilard and Chalmers. No evidence of a photo-electric disintegration amongst the radioactive elements has yet been found.

scholarly journals Advances at TRIUMF-ISAC and decay of neutron-rich Cd studied with GRIFFIN

2018 ◽  
Vol 193 ◽  
pp. 04011
Author(s):  
P.E. Garrett ◽  
N. Bernier ◽  
R. Dunlop ◽  
A.D. MacLean ◽  
V. Bildstein ◽  
...  
Keyword(s):  
Time Distribution ◽  
Ground States ◽  
Neutron Number ◽  
Current Status ◽  
Neutron Decay ◽  
Delayed Neutron ◽  
Abundance Peak ◽  
Γ Rays ◽  
Γ Ray

The β-decay half lives of nuclei near the r-process path are critical information required for abundance calculations, especially those near neutron number N = 82. Specifically, the nuclei below doubly-magic 132Sn are key, and play an important role in the formation and shape of the second r-process abundance peak. The half lives in this region are challenging to measure due to the significant β-delayed neutron decay branches and the population of isomeric states with half lives comparable to the ground states. However, by measuring the time distribution of γ rays, these complications can be eliminated. This requires, however, a very effcient γ-ray spectrometer since the production of isotopes in this region is very limited. The new GRIFFIN array at TRIUMF-ISAC provides the high effciency required for these measurements. Recent improvements in the quality of the beams produced at TRIUMF, employing the IG-LIS device, are outlined, as well as the current status of the ARIEL facility. The GRIFFIN spectrometer and its use are briefly described. The experiment to measure the half lives of 128-130Cd is outlined and the results given, and some examples of the power of GRIFFIN to expand decay schemes, specifically for the decay of 128Cd to 128In, are given.

Sign in / Sign up

Export Citation Format

Share Document