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

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.

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SPALLATION YIELDS FROM HIGH ENERGY PROTON BOMBARDMENT OF HEAVY ELEMENTS

Canadian Journal of Physics ◽

10.1139/p57-003 ◽

1957 ◽

Vol 35 (1) ◽

pp. 21-37 ◽

Cited By ~ 15

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The Monte Carlo calculations of McManus and Sharp (unpublished) for the prompt nuclear processes occurring upon bombardment of heavy elements by 400 Mev.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.

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

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1973.0135 ◽

1973 ◽

Vol 335 (1603) ◽

pp. 431-452 ◽

Cited By ~ 1

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.

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

Molecules ◽

10.3390/molecules24061095 ◽

2019 ◽

Vol 24 (6) ◽

pp. 1095 ◽

Cited By ~ 3

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.

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High Energy Proton Irradiation of Pure Titanium

MRS Proceedings ◽

10.1557/proc-650-r3.1 ◽

2000 ◽

Vol 650 ◽

Cited By ~ 1

Author(s):

Teresa Leguey ◽

Claude Bailat ◽

Nadine Baluc ◽

Max Victoria

Keyword(s):

Proton Irradiation ◽

Tensile Deformation ◽

Pure Titanium ◽

High Energy ◽

Significant Loss ◽

Fcc Metals ◽

Defect Clusters ◽

Energy Proton ◽

Transmission Electron ◽

Mev Protons

ABSTRACTPolycrystalline specimens of hcp pure titanium have been irradiated at 300-320 K with 590 MeV protons to doses ranging between 10-3 and 3×10-2 dpa. Combination of tensile deformation experiments and transmission electron microscopy observations revealed that irradiation produces slight hardening of the material, related to the irradiation-induced formation of defect clusters, but not significant loss of ductility. Plastic deformation of irradiated titanium is homogeneous. It occurs via propagation of dislocations through a cloud of defect clusters, leading to their annihilation and the formation of a cellular dislocation structure together with twins. This mechanical behavior is similar to what was previously observed for pure fcc metals, the formation of twins being however intrinsic to deformation of hcp titanium.

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Total cross sections of eγ → $$ eX\overline{X} $$ processes with X = μ, γ, e via multiloop methods

Journal of High Energy Physics ◽

10.1007/jhep01(2021)144 ◽

2021 ◽

Vol 2021 (1) ◽

Author(s):

Roman N. Lee ◽

Alexey A. Lyubyakin ◽

Vyacheslav A. Stotsky

Keyword(s):

Cross Section ◽

Cross Sections ◽

Elliptic Integral ◽

High Energy ◽

Calculation Methods ◽

Complete Elliptic Integral ◽

Total Cross Sections ◽

Multiloop Calculation ◽

The Cross ◽

Analytical Expressions

Abstract Using modern multiloop calculation methods, we derive the analytical expressions for the total cross sections of the processes e−γ →$$ {e}^{-}X\overline{X} $$ e − X X ¯ with X = μ, γ or e at arbitrary energies. For the first two processes our results are expressed via classical polylogarithms. The cross section of e−γ → e−e−e+ is represented as a one-fold integral of complete elliptic integral K and logarithms. Using our results, we calculate the threshold and high-energy asymptotics and compare them with available results.

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Saturation effects in SIDIS at very forward rapidities

Journal of High Energy Physics ◽

10.1007/jhep07(2021)196 ◽

2021 ◽

Vol 2021 (7) ◽

Author(s):

E. Iancu ◽

A. H. Mueller ◽

D. N. Triantafyllopoulos ◽

S. Y. Wei

Keyword(s):

Inelastic Scattering ◽

Cross Section ◽

Cross Sections ◽

Virtual Photon ◽

Large Fraction ◽

Quark Distribution ◽

High Energy ◽

Longitudinal Momentum ◽

Black Disk ◽

Gluon Saturation

Abstract Using the dipole picture for electron-nucleus deep inelastic scattering at small Bjorken x, we study the effects of gluon saturation in the nuclear target on the cross-section for SIDIS (single inclusive hadron, or jet, production). We argue that the sensitivity of this process to gluon saturation can be enhanced by tagging on a hadron (or jet) which carries a large fraction z ≃ 1 of the longitudinal momentum of the virtual photon. This opens the possibility to study gluon saturation in relatively hard processes, where the virtuality Q2 is (much) larger than the target saturation momentum $$ {Q}_s^2 $$ Q s 2 , but such that z(1 − z)Q2 ≲ $$ {Q}_s^2 $$ Q s 2 . Working in the limit z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we predict new phenomena which would signal saturation in the SIDIS cross-section. For sufficiently low transverse momenta k⊥ ≪ Qs of the produced particle, the dominant contribution comes from elastic scattering in the black disk limit, which exposes the unintegrated quark distribution in the virtual photon. For larger momenta k⊥ ≳ Qs, inelastic collisions take the leading role. They explore gluon saturation via multiple scattering, leading to a Gaussian distribution in k⊥ centred around Qs. When z(1 − z)Q2 ≪ Q2, this results in a Cronin peak in the nuclear modification factor (the RpA ratio) at moderate values of x. With decreasing x, this peak is washed out by the high-energy evolution and replaced by nuclear suppression (RpA< 1) up to large momenta k⊥ ≫ Qs. Still for z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we also compute SIDIS cross-sections integrated over k⊥. We find that both elastic and inelastic scattering are controlled by the black disk limit, so they yield similar contributions, of zeroth order in the QCD coupling.

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Study of the 232Th(n,f) Cross section at NCSR ‘Demokritos’ using Micromegas Detectors

HNPS Proceedings ◽

10.12681/hnps.2994 ◽

2020 ◽

Vol 27 ◽

pp. 106

Author(s):

Sotirios Chasapoglou ◽

A. Tsantiri ◽

A. Kalamara ◽

M. Kokkoris ◽

V. Michalopoulou ◽

...

Keyword(s):

Cross Section ◽

Cross Sections ◽

Nuclear Reactions ◽

Detection Efficiency ◽

High Energy ◽

Tandem Accelerator ◽

Line Detector ◽

Accelerator Driven Systems ◽

The Masses

The accurate knowledge of neutron-induced fission cross sections in actinides, is of great importance when it comes to the design of fast nuclear reactors, as well as accelerator driven systems. Specifically for the 232Th(n,f) case, the existing experimental datasets are quite discrepant in both the low and high energy MeV regions, thus leading to poor evaluations, a fact that in turn implies the need for more accurate measurements.In the present work, the total cross section of the 232Th(n,f) reaction has been measured relative to the 235U(n,f) and 238U(n,f) ones, at incident energies of 7.2, 8.4, 9.9 MeV and 14.8, 16.5, 17.8 MeV utilizing the 2H(d,n) and 3H(d,n) reactions respectively, which generally yield quasi-monoenergetic neutron beams. The experiments were performed at the 5.5 MV Tandem accelerator laboratory of N.C.S.R. “Demokritos”, using a Micromegas detector assembly and an ultra thin ThO2 target, especially prepared for fission measurements at n_ToF, CERN during its first phase of operations, using the painting technique. The masses of all actinide samples were determined via α-spectroscopy. The produced fission yields along with the results obtained from activation foils were studied in parallel, using both the NeusDesc [1] and MCNP5 [2] codes, taking into consideration competing nuclear reactions (e.g. deuteron break up), along with neutron elastic and inelastic scattering with the beam line, detector housing and experimental hall materials. Since the 232Th(n,f) reaction has a relatively low energy threshold and can thus be affected by parasitic neutrons originating from a variety of sources, the thorough characterization of the neutron flux impinging on the targets is a prerequisite for accurate cross-section measurements, especially in the absence of time-of-flight capabilities. Additional Monte-Carlo simulations were also performed coupling both GEF [3] and FLUKA [4] codes for the determination of the detection efficiency.

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