GAMMA RADIATION FROM THE PROTON BOMBARDMENT OF BORON TEN

1956 ◽  
Vol 34 (4) ◽  
pp. 381-388 ◽  
Author(s):  
G. B. Chadwick ◽  
T. K. Alexander ◽  
J. B. Warren
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Gamma Rays ◽  
Lower Energy ◽  
Sodium Iodide ◽  
Scintillation Counter ◽  
Proton Bombardment ◽  
Broad Resonance ◽  
Energy Formula ◽  
Cascade Transitions

The gamma rays resulting from the bombardment of B10 with protons of energies from 0.5 to 2.0 Mev. have been observed with a sodium iodide scintillation counter. Capture radiation, of energy[Formula: see text]showed a broad resonance at Ep = 1135 ± 15 kev. At this energy, the radiation had an angular distribution of the form 1 + (0.50 ± 0.05)cos2θ and a total cross section (3.5 ± 1.0)10−30 cm.2 Several lower energy radiations were also observed and assigned tentatively to cascade transitions in C11.The cross section for the 430 kev. radiation from the reaction B10(p, αγ)Be7 was found to be 0.21 ± 0.05 barn at Ep = 1.52 Mev. This radiation was found to be isotropic.

The Angular Distribution of 12-Mev Gamma Rays from Proton Bombardment ofB11

1953 ◽  
Vol 91 (4) ◽  
pp. 915-917 ◽  
Author(s):  
G. L. Jenkins ◽  
L. W. Cochran ◽  
B. D. Kern ◽  
T. M. Hahn
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Proton Bombardment

Prompt gamma rays and X rays from supernovae

1968 ◽  
Vol 46 (10) ◽  
pp. S476-S480 ◽  
Author(s):  
Stirling A. Colgate
Keyword(s):  
Surface Layer ◽  
Gamma Rays ◽  
Lower Energy ◽  
Mean Free Path ◽  
Prompt Gamma ◽  
X Rays ◽  
Energy Factor ◽  
The Earth ◽  
Photon Pulse ◽  
Energy Formula

The hydrodynamic origin of cosmic rays (Colgate and Johnson 1960) depends upon the shock ejection of the outer layers of the supernova. The increase in energy of the shock to c2 per gram occurs relatively deep within the star where the fraction, F, of mass external to this layer is 10−4. The relativistic shock wave continues to increase in strength in the decreasing density of the envelope. When the shock "breaks through" the surface denned as one Compton scattering mean free path at radius R, then the energy factor [Formula: see text]. The temperature in the proper frame of the shock is determined by the condition aT4 = 2γs2ρ0, where ρ0 is the initial rest density ahead of the shock. For a typical presupernova star, [Formula: see text], and polytrope of index 3, the temperature becomes (1.7–2) × 105 eV at the surface layer. Photons emitted from the moving surface layer will be Doppler-shifted from their mean proper frame value of 3kT to a final energy [Formula: see text].Photons originating in, and emitted from, the surface layer before the layer expands adiabatically will have the upper limiting energy. As adiabatic expansion of subsequent layers takes place, photons diffusing from greater depths will be emitted at sequentially lower energy. The total energy in the photon pulse from the surface layer becomes [Formula: see text] ergs, or 50 ergs/cm2 at the earth for a supernova within our galaxy. The time of emission becomes [Formula: see text] (Petschek 1967).

CAPTURE RADIATION AND NEUTRONS FROM THE BOMBARDMENT OF C14 WITH PROTONS

1955 ◽  
Vol 33 (8) ◽  
pp. 441-456 ◽  
Author(s):  
G. A. Bartholomew ◽  
F. Brown ◽  
H. E. Gove ◽  
A. E. Litherland ◽  
E. B. Paul
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Total Yield ◽  
Isotopic Spin ◽  
Proton Bombardment ◽  
Neighboring State ◽  
Γ Rays ◽  
Γ Ray

The yield and angular distribution of ground state γ-rays and of neutrons resulting from the proton bombardment of C14 have been studied for proton energies from 0.2 to 2.5 Mev. Assignments of spin and parity are made to most of the resonances observed in this range. A single particle proton state which may have isotopic spin 3/2 has been observed. The interference of this state, which has spin 1/2+, with a neighboring state of the same spin and parity is observed in the total yield of the ground state γ-ray. Three states below the neutron threshold which have been observed previously in the N14(d, p)N15 reaction are also observed in the C14(p, γ)N15 reaction. The N14(n, p)C14 cross section at thermal energies can be accounted for by a resonance observed in this experiment, but another resonance below the neutron threshold must be assumed to account for the thermal (n, n) and (n, γ) cross sections.

Angular Distribution of 12- and 16-Mev Gamma Rays from the Proton Bombardment of a Thin Boron Target

1954 ◽  
Vol 96 (5) ◽  
pp. 1337-1339 ◽  
Author(s):  
H. H. Givin ◽  
G. K. Farney ◽  
T. M. Hahn ◽  
B. D. Kern
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Proton Bombardment

THE CAPTURE OF PROTONS BY DEUTERONS

1962 ◽  
Vol 40 (4) ◽  
pp. 402-411 ◽  
Author(s):  
G. M. Griffiths ◽  
E. A. Larson ◽  
L. P. Robertson
Keyword(s):  
Angular Distribution ◽  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section ◽  
Gamma Rays ◽  
Proton Energy ◽  
P Wave ◽  
S Wave ◽  
Proton Capture ◽  
The Cross

The cross section and angular distribution of gamma rays for the reaction D(p,γ)He3 have been measured for proton energies from 275 kev to 1.75 Mev. For 275-kev protons the total cross section is 0.97 ± 0.11 microbarns and for 985-kev protons it is 3.5 ± 0.38 microbarns. The angular distribution has the form (sin2θ+b) where b is small. b is found to increase with decreasing proton energy, contrary to some previous results from this laboratory, and the energy dependence of b and of the cross section suggests that the sin2 θ part of the cross section is due to the capture of p-wave protons and the b part is due to s-wave proton capture.

scholarly journals On the scattering of fast neutrons by protons

1947 ◽  
Vol 191 (1025) ◽  
pp. 195-209 ◽  
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Cosmic Ray ◽  
Fast Neutrons ◽  
Meson Mass ◽  
Nuclear Forces ◽  
Total Scattering ◽  
Empirical Results ◽  
Meson Theory ◽  
Total Scattering Cross Section

The features of the scattering of fast neutrons by protons are calculated using the Møller- Rosenfeld version of the meson theory of nuclear forces. The experimental results of Occhialini & Powell are used to check the predicted angular distribution of the scattered particles and to determine the mass of the meson; the meson mass indicated is about 215 electronic masses, which agrees with the mass of cosmic ray mesons. The total scattering cross-section predicted by the theory agrees with the empirical results.

Evidence for the Photoemission Nature of Gd 4f Resonant Photoemission

1998 ◽  
Vol 524 ◽  
Author(s):  
S. R. Mishra ◽  
T. R. Cummins ◽  
W. J. Gammon ◽  
G. D. Waddill ◽  
G. Van der-Laan ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Photon Energy ◽  
Photoelectron Spectroscopy ◽  
Emission Cross Section ◽  
Linear Dichroism ◽  
Constructive Interference ◽  
Resonant Photoemission ◽  
Magnetic Linear Dichroism ◽  
Spectroscopy Experiment

ABSTRACTThe constructive interference between direct and indirect channels above the absorption threshold of a core level leads to a massive increase in the emission cross section leading to a phenomenon called “resonant photoemission”. Using novel magnetic linear dichroism in angular distribution photoelectron spectroscopy experiment we have tried to understand the nature of the resonant photoemission process in Gd metal. The presence of dichroism in Gd 4f photoemission intensity at a photon energy corresponding to resonant photoemission clearly demonstrates the photoemission-like nature of the resonant photoemission process.

GAMMA-RAY BURSTS AS VHE-UHE SOURCES

2008 ◽  
Vol 17 (09) ◽  
pp. 1319-1332
Author(s):  
PETER MÉSZÁROS
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Lower Energy ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Model Parameters ◽  
Fundamental Interaction ◽  
Acceleration Mechanism ◽  
Inverse Compton ◽  
Tev Gamma Rays

Gamma-ray bursts are capable of accelerating cosmic rays up to GZK energies Ep ~ 1020 eV, which can lead to a flux at Earth comparable to that observed by large EAS arrays such as Auger. The semi-relativistic outflows inferred in GRB-related hypernovae are also likely sources of somewhat lower energy cosmic rays. Leptonic processes, such as synchrotron and inverse Compton, as well as hadronic processes, can lead to GeV-TeV gamma-rays measurable by GLAST, AGILE, or ACTs, providing useful probes of the burst physics and model parameters. Photo-meson interactions also produce neutrinos at energies ranging from sub-TeV to EeV, which will be probed with forthcoming experiments such as IceCube, ANITA and KM3NeT. This would provide information about the fundamental interaction physics, the acceleration mechanism, the nature of the sources and their environment.

Scintillation Counter Study of Gamma Rays from Proton Capture in Sodium

1954 ◽  
Vol 94 (5) ◽  
pp. 1311-1316 ◽  
Author(s):  
R. R. Carlson ◽  
E. H. Geer ◽  
E. B. Nelson
Keyword(s):  
Gamma Rays ◽  
Scintillation Counter ◽  
Proton Capture
Sign in / Sign up

Export Citation Format

Share Document