SPALLATION YIELDS FROM HIGH ENERGY PROTON BOMBARDMENT OF HEAVY ELEMENTS

1957 ◽  
Vol 35 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. D. Jackson
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Heavy Elements ◽  
Collective Effects ◽  
Comparison With Experiment ◽  
Energy Proton ◽  
Stringent Test ◽  
Neutron Evaporation ◽  
Nuclear Processes ◽  
Mev Protons

The Monte Carlo calculations of McManus and Sharp (unpublished) for the prompt nuclear processes occurring upon bombardment of heavy elements by 400 Mev. protons are combined with a description of the subsequent neutron evaporation to determine spallation cross sections for comparison with experiment. The model employed is a schematic one which suppresses the detailed characteristics of individual nuclei, but gives the over-all behavior to be expected. Many-particle and collective effects such as alpha particle emission and fission are ignored. The computed cross sections are presented in a variety of different graphical forms which illustrate quantitatively the qualitative picture of high energy reactions first given by Serber (1947). The calculations are in general agreement with existing data when fission is not an important effect, but the agreement does not imply a very stringent test of the various features of the model.

Measurements of Displacement Cross Section of Tungsten under 389-MeV Proton Irradiation and Thermal Damage Recovery

2021 ◽  
Vol 1024 ◽  
pp. 95-101
Author(s):  
Yosuke Iwamoto ◽  
Makoto Yoshida ◽  
Hiroki Matsuda ◽  
Shin Ichiro Meigo ◽  
Daiki Satoh ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Thermal Conduction ◽  
Thermal Damage ◽  
Proton Irradiation ◽  
High Energy ◽  
Wire Sample ◽  
Energy Proton ◽  
Measured Displacement ◽  
Mev Protons

For validating the number of displacements per atom (dpa) for tungsten under high-energy proton irradiation, we measured displacement cross sections related to defect-induced electrical resistivity changes in a tungsten wire sample under irradiation with 389-MeV protons under 10 K. The Gifford–McMahon cryocooler was used to cool the sample using a conductive coolant via thermal conduction plates of oxygen-free high-conductivity copper and electrical insulation sheets of aluminum nitride ceramic. In this experiment, the displacement cross section was 1612 ± 371 b for tungsten at 389 MeV. A comparison of the experimental displacement cross sections of tungsten with the calculated results obtained using Norgett–Robinson–Torrens (NRT) dpa and athermal recombination-corrected (arc) dpa cross sections indicates that arc-dpa was in better agreement with the experimental data than NRT-dpa; this is similar to the displacement cross sections of copper. From the measurements of damage recovery of the accumulated defects in tungsten through isochronal annealing, which is related to the defect concentration of the sample, approximately 20% of the damage was recovered at 60 K. This trend was similar to those observed in other experimental results for reactor neutrons.

Formation Cross Sections of Nucleides Produced from Heavy Elements by High-energy Proton Bombardment

1974 ◽  
Vol 29 (5) ◽  
pp. 822-825
Author(s):  
B. K. Gupta ◽  
S. Das
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Heavy Elements ◽  
Proton Bombardment ◽  
High Energy Proton ◽  
Energy Proton

Abstract Theoretical cross sections for the production of elements from 209Bi and natural copper by high-energy proton bombardment have been calculated.

A SCHEMATIC MODEL FOR (p, xn) CROSS SECTIONS IN HEAVY ELEMENTS

1956 ◽  
Vol 34 (8) ◽  
pp. 767-779 ◽  
Author(s):  
J. D. Jackson
Keyword(s):  
Cross Sections ◽  
Reaction Cross ◽  
Heavy Elements ◽  
Total Reaction Cross Section ◽  
Schematic Model ◽  
Nuclear Temperature ◽  
A Minor ◽  
Neutron Evaporation ◽  
Average Neutron ◽  
Evaporation Stage

A schematic model for the description of (p, xn) reactions in heavy elements is presented. Reactions are divided into two steps, a prompt multiple collision process, followed by an evaporation stage. The various prompt processes are given by the results of Monte Carlo calculations, while the evaporation processes are described by a simplified model assuming constant nuclear temperatures and only neutron evaporation. The resulting (p, xn), and to a minor degree (p, pxn), cross sections are compared with the experimental data of Bell and Skarsgard (1956) in the energy range up to 100 Mev. With an average neutron binding energy of around 7.3 Mev., a nuclear temperature of about 1.8 Mev., and a nuclear radius of 8.0 × 10−13 cm., a reasonable over-all fit can be made to the data for Pb206, Pb207, Pb208, and Bi209. Characteristic fluctuations in the experimental results for the (p, 2n), (p, 3n), and (p, 4n) reactions for all targets seem to be attributable to variations in the total reaction cross section, and are not reproduced by the present model.

scholarly journals Highest energy proton–nucleus cross-sections

2018 ◽  
Vol 33 (40) ◽  
pp. 1850242 ◽  
Author(s):  
L. Stodolsky
Keyword(s):  
Cosmic Rays ◽  
Cross Sections ◽  
High Energy ◽  
High Energy Proton ◽  
Proton Proton ◽  
Energy Proton ◽  
Black Disc ◽  
Simple Generalization ◽  
Very High Energy ◽  
Very High

The description of very high energy proton–proton cross-sections in terms of a “black disc” with an “edge” allows a simple generalization to highest energy proton–nucleus cross-sections. This results in a leading ln2W term and a ln W term whose coefficient depends linearly on the radius of the nucleus (W the c.m. energy). The necessary parameters are determined from the fits to p–p data. Since the coefficient of the ln W term is rather large, it is doubtful that the regime of ln2W dominance can be reached with available energies in accelerators or cosmic rays. However, the ln W term can be relevant for highest energy cosmic rays in the atmosphere, where a large increase for the cross-section on nitrogen is expected. Tests of the theory should be possible by studying the coefficient of ln W at p-nucleus colliders.

Proton-proton scattering at the C. E. R. N. Intersecting Storage Rings

1973 ◽  
Vol 335 (1603) ◽  
pp. 431-452 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Energy ◽  
Storage Rings ◽  
The Other ◽  
Proton Scattering ◽  
High Energy Proton ◽  
Proton Proton ◽  
Total Cross Sections ◽  
Energy Proton

The main features of the C. E. R. N. Intersecting Storage Rings (I. S. R.) are reviewed, together with results obtained in 1971 and 1972 on elastic scattering and total cross-sections. The main result is a 10% increase of the total proton-proton cross-section in the I. S. R. energy range. The simplest picture of high energy proton-proton scattering which emerges from this and the other data, is briefly discussed.

scholarly journals Defining Processing Times for Accelerator Produced 225Ac and Other Isotopes from Proton Irradiated Thorium

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1095 ◽  
Author(s):  
Jonathan Fitzsimmons ◽  
Justin Griswold ◽  
Dmitri Medvedev ◽  
Cathy Cutler ◽  
Leonard Mausner
Keyword(s):  
Cross Sections ◽  
Proton Irradiation ◽  
High Energy ◽  
Time Dependent ◽  
High Energy Proton ◽  
Processing Times ◽  
Energy Proton ◽  
Thorium Target

During the purification of radioisotopes, decay periods or time dependent purification steps may be required to achieve a certain level of radiopurity in the final product. Actinum-225 (Ac-225), Silver-111 (Ag-111), Astatine-211 (At-211), Ruthenium-105 (Ru-105), and Rhodium-105 (Rh-105) are produced in a high energy proton irradiated thorium target. Experimentally measured cross sections, along with MCNP6-generated cross sections, were used to determine the quantities of Ac-225, Ag-111, At-211, Ru-105, Rh-105, and other co-produced radioactive impurities produced in a proton irradiated thorium target at Brookhaven Linac Isotope Producer (BLIP). Ac-225 and Ag-111 can be produced with high radiopurity by the proton irradiation of a thorium target at BLIP.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

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