MEASUREMENTS OF SPECTRAL AND ANGULAR DISTRIBUTIONS OF SECONDARY GAMMA-RAYS IN MATTER

1955 ◽  
Vol 33 (2) ◽  
pp. 96-109 ◽  
Author(s):  
G. N. Whyte
Keyword(s):  
Gamma Rays ◽  
Pulse Height ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Barrier Thickness ◽  
Crystal Spectrometer ◽  
Theoretical Predictions ◽  
The Face ◽  
Concrete Barrier ◽  
Secondary Gamma Radiation

The distribution in energy and angle of the secondary gamma radiation emerging from the face of a concrete barrier containing a point source of cobalt-60 has been measured as a function of barrier thickness. Results on energy spectra and angular distributions are presented, and some of their features are compared with theoretical predictions. The operation of the two-crystal spectrometer and the photographic system for recording pulse-height distributions are described in some detail.

Gamma rays and high-energy neutrons in the atmosphere

1968 ◽  
Vol 46 (10) ◽  
pp. S1030-S1033 ◽  
Author(s):  
M. V. K. Apparao ◽  
R. R. Daniel ◽  
George Joseph ◽  
G. S. Gokhale ◽  
P. J. Lavakare ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Counting Rate ◽  
Plastic Scintillator ◽  
Pulse Height ◽  
Growth Curves ◽  
High Energy ◽  
Cutoff Rigidity ◽  
Energy Formula ◽  
Γ Rays ◽  
Γ Ray

In continuation of our earlier experiments studying the emission of solar neutrons, we have now developed detector systems which respond to γ rays of energy 1–5 MeV and neutrons of energy [Formula: see text]. The two detectors are almost identical. Each consists of a CsI (Na) crystal (B) of diameter 3.8 cm, completely enclosed in a tapered cylinder of plastic scintillator (A) operated in anticoincidence; the crystals have thicknesses of 2.4 and 1.2 cm respectively. A balloon carrying these detectors was flown on March 16, 1967 over Hyderabad, India (vertical cutoff rigidity 16.9 GV) and floated at a ceiling altitude of 6.0 mb for 1 hour. In addition to γ-ray and neutron events (AB), events A and AB were also continuously monitored throughout the flight. Pulses corresponding to 1–5 MeV in the 2.4-cm crystal (γ rays) and 6–40 MeV in the 1.2-cm crystal (high-energy neutrons) were analyzed by a 64-channel pulse-height analyzer. On the basis of the pulse-height distributions and γ-ray efficiencies in the two crystals, we attribute events of 1–5 MeV energy from the thicker crystal to γ rays and those > 10 MeV in energy from the thinner one to stars produced by high-energy neutrons [Formula: see text] in the crystal. Atmospheric growth curves for γ rays and neutrons have been obtained; these growth curves as well as those for events A and AB show the normal features of the Pfotzer maximum, steady decreases up to the ceiling altitude, and a constant counting rate at ceiling. The atmospheric counting rates at ceiling altitude give for γ rays of energy 1–5 MeV a flux of ~1 photon per cm2 s and for neutrons of energy [Formula: see text] a flux of ~0.1 neutron per cm2 s. No evidence for a solar component in either channel was found.

Nuclear g Factors in 55Fe

1973 ◽  
Vol 51 (7) ◽  
pp. 707-712 ◽  
Author(s):  
P. G. Kerr ◽  
A. W. Gibb ◽  
J. A. Cameron
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Target Material ◽  
Internal Field ◽  
Angular Distributions ◽  
Mixing Ratios ◽  
Decay Gamma ◽  
G Factors

The (α,n) reaction on natural chromium has been used to study levels in 55Fe up to 2.5 MeV excitation. Intensities and angular distributions of the decay gamma rays were measured, yielding branching and E2/M1 mixing ratios. In a magnetized target of the alloy Cr20Fe80, the rotation of the angular distributions was observed. Using recently determined lifetimes for the excited states and the average internal field of 277 kOe measured in the target material by Mössbauer absorption, the following g factors are obtained:[Formula: see text]

Spectroscopic Study of 32S Through the 31P(d,n)32S Reaction

1974 ◽  
Vol 52 (14) ◽  
pp. 1288-1294 ◽  
Author(s):  
A. H. Hussein ◽  
G. C. Neilson ◽  
W. J. McDonald ◽  
W. K. Dawson
Keyword(s):  
Spectroscopic Study ◽  
Shell Model ◽  
Cross Sections ◽  
Differential Cross ◽  
Time Of Flight ◽  
Angular Distributions ◽  
Absolute Differential ◽  
Spectroscopic Factors ◽  
Model Predictions ◽  
Theoretical Predictions

The 31P(d,n)32S reaction has been studied at deuteron energies of 4.0 and 5.45 MeV. Neutron energies were measured by time of flight. Absolute differential cross sections of seven levels in 32S have been measured and compared with the theoretical predictions of both the DWBA and compound statistical theories. Analysis of the angular distributions yielded lP values and absolute spectroscopic factors. These results have been compared with those from other experiments and shell model predictions.

A STUDY OF THE Be9(He3, n)C11 REACTION

1963 ◽  
Vol 41 (7) ◽  
pp. 1036-1046 ◽  
Author(s):  
L. van der Zwan ◽  
A. T. Stewart ◽  
J. Y. Park ◽  
E. Merzbacher
Keyword(s):  
Compound Nucleus ◽  
Cross Sections ◽  
Interaction Mechanism ◽  
Direct Interaction ◽  
Particle Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Proton Recoil ◽  
The Cross ◽  
Photographic Emulsions

The energy spectra and angular distributions of the emergent neutrons from the Be9(He3, n)C11 reaction have been obtained for an incident He3-particle energy of 2 Mev with the technique of observing proton recoil in photographic emulsions. The cross sections were normalized to Be9(He3, p)B11 data observed simultaneously at 90° to the beam. The lack of similarity in the (He3, n) and (He3, p) mirror reactions to some residual states suggests a direct interaction mechanism rather than compound nucleus. An attempt to analyze some of the data in terms of double particle stripping has been made.

scholarly journals Nuclear disintegrations produced by cosmic rays

1949 ◽  
Vol 196 (1046) ◽  
pp. 325-343 ◽  
Keyword(s):  
Cosmic Radiation ◽  
High Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Wide Range ◽  
High Energy Tail ◽  
Energy And Angular Distributions ◽  
Photographic Emulsions ◽  
Α Particles

Measurements have been made on the energy and angular distributions of the charged particles from disintegration ‘stars’ produced in the silver and bromine nuclei of photographic emulsions exposed to cosmic radiation. The observations extended over a wide range of excitation energies (100 to 700 MeV). The energy spectra and angular distributions of the protons can be explained in all cases by simple evaporation theory. This energy distribution shows also a high-energy tail consisting of direct knock-on protons and slow mesons. At high excitation energies the α-particles exhibit collimation effects which are probably due to localized ‘boiling’ or a form of fission.

Sign in / Sign up

Export Citation Format

Share Document