Radiation Defect Study in the P-Type Copper Seleind

1991 ◽  
Vol 234 ◽  
Author(s):  
N. D. Marchuk ◽  
A. P. Dolgolenko
Keyword(s):  
Fast Neutron ◽  
Nuclear Reaction ◽  
Radiation Defect ◽  
Neutron Fluence ◽  
Fast Neutrons ◽  
Thermal Neutrons ◽  
Reactor Irradiation ◽  
Defect Clusters ◽  
High Fluences ◽  
P Type

ABSTRACTP-Cu2-δ Se(δ=0.025) samples, self-doped through a departure from the stoichiometry(po= 4.8·1020) and cadmium-doped up to a concentration po= 5.6·1020cm−3 were studied in the course of their irradiation in a reactor up to a fluance of -6·1020 n·cm−2 of fast neutrons at a temperature of -500-550° C. The dependence of the resistivity and thermo-emf on the fast neutron fluence is described in terms of the theory of effective medium and representation of defect clusters as dielectric inclusions in a conducting matrix of p-Cu2Se(Cd) and p-Cu2_δSe samples.Defect clusters of a mean radius of -27 Å are shown to appear not only because of scattering of the fast pile neutrons on copper and selenium atoms, but also due to a nuclear reaction 112Cd(n,γ)114Cd on thermal neutrons with an efficiency of 3.43 cm−1. Increase of the conductivity in the process of the reactor irradiation of p-Cu2-δSe at small fluences of fast neutrons and appearance of a whitish deposit of selenium on the surface of samples after high fluences of fast neutrons were observed.

scholarly journals Computer Modeling of Displacement Cascades in Beryllium Irradiated with Intensive Neutron Flux

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
T. Troev ◽  
N. Nankov ◽  
L. Petrov ◽  
E. Popov
Keyword(s):  
Neutron Flux ◽  
Fast Neutron ◽  
Computer Modeling ◽  
Computer Simulations ◽  
Neutron Fluence ◽  
Fast Neutrons ◽  
Radiation Defects ◽  
Helium Concentration ◽  
Vacancy Clusters ◽  
Displacement Cascades

Computer simulations of the radiation defects created in beryllium irradiated by fast neutrons (E>0.1 MeV) using the Geant4 and SRIM packages were carried out. The atom cascade displacements in Be at a neutron fluence of 1.6×1020 n/cm2 were determined to be 0.06 dpa and the helium concentration was calculated to be 168 appm. The concentration of 6Li has been estimated to be 5% in comparison to the He concentration. Nanoscale calculations were done in 30×30×30 nm cube of fast neutron-irradiated Be. A correlation between the Be primary knock-on atom (PKA) energies and the damage cascades has been established. The final defect distributions of single vacancies, divacancies, and small vacancy clusters were examined. Our results indicate that the damages caused by He atoms are about 3 times less than damages caused by Be primary knock-on atoms (PKAs).

scholarly journals Feasibility Study of Copper-64 Radioisotope Production by Secondary Fast Neutron Bombardment

2021 ◽  
Vol 927 (1) ◽  
pp. 012034
Author(s):  
I Kambali ◽  
I R Febrianto
Keyword(s):  
Neutron Flux ◽  
Fast Neutron ◽  
Nuclear Reaction ◽  
Target Thickness ◽  
Total Radioactivity ◽  
Radioactive Isotopes ◽  
Fast Neutrons ◽  
Fast Neutron Flux ◽  
Section Data ◽  
Theranostic Agent

Abstract As a beta and positron emitter, copper-64 (Cu-64) has been coined a theranostic agent in nuclear medicine. Copper-64 is generally produced by bombarding a nickel-64 target with a proton beam via 64Ni(p,n)64Cu nuclear reaction. In this work, secondary fast neutrons are proposed to produce Cu-64 radioisotope via 64Zn(n,p)64Cu nuclear reaction. The secondary fast neutrons were produced by a 10 MeV proton-irradiated primary titanium (Ti) target simulated using the PHITS 3.16 code. In the simulation, the Ti target thickness was varied from 0.01 to 0.1 cm to obtain the optimum secondary fast neutron flux, which was calculated in the rear, radial, and front directions. The Cu-64 radioactivity yield was then computed using the TENDL 2019 nuclear cross-section data. Also, the expected radioactive impurities during Cu-64 production were predicted. The simulation results indicated that the total fast neutron flux resulted from the 10-MeV proton bombarded Be target was 1.70x1012 n/cm2s. The maximum integrated Cu-64 radioactivity yield was 2.33 MBq/µAh when 0.03 cm thick Ti target was shot with 10-MeV protons. The most significant impurities predicted during the bombardment were radioactive isotopes e.g., Co-61, and Zn-65, with the total radioactivity yield estimated to be 0.28 Bq/µAh.

ELECTRIC CONDUCTIVITY OF ALUMINUM ALLOYS DEPENDING ON FAST NEUTRON FLUENCE

2020 ◽  
Vol 4 (1) ◽  
pp. 65-72
Author(s):  
Davronbek Tojiboev ◽  
◽  
Fakhrulla Kungurov ◽  
Sapar Baitelesov ◽  
Ilkhom Hikmatov ◽  
...  
Keyword(s):  
Solid Solution ◽  
Aluminum Alloys ◽  
Fast Neutron ◽  
Electric Conductivity ◽  
Neutron Fluence ◽  
Nonlinear Dependence ◽  
Fast Neutrons ◽  
X Ray ◽  
Order Of Magnitude ◽  
Good Agreement

The nonlinear dependence of the resistivity on the dose and temperature was determined. On the basis of X-ray structure of the alloy is shown that the alloy SAV-1 is a solid solution in which the average static mixing of atoms in order of magnitude compared with their dynamic displacements caused by thermal motion. It was investigated structure and conductivity of the reactor structural alloys SAV-1 irradiated with fast neutrons ata fluence of 1016–1021nsm-2in the temperature range290 -490 K. It is shown that for unirradiated alloySAV-1 calculated value of the resistivity of the alloy is in good agreement with the experimental value in studied temperature range.

Annealing Of Radiation Damage in Tungsten

1970 ◽  
Vol 28 ◽  
pp. 412-413
Author(s):  
Robert C. Rau ◽  
John Moteff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Neutron Fluence ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Polycrystalline Tungsten ◽  
Transmission Electron ◽  
Radiation Induced

Transmission electron microscopy has been used to study the thermal annealing of radiation induced defect clusters in polycrystalline tungsten. Specimens were taken from cylindrical tensile bars which had been irradiated to a fast (E > 1 MeV) neutron fluence of 4.2 × 1019 n/cm2 at 70°C, annealed for one hour at various temperatures in argon, and tensile tested at 240°C in helium. Foils from both the unstressed button heads and the reduced areas near the fracture were examined.Figure 1 shows typical microstructures in button head foils. In the unannealed condition, Fig. 1(a), a dispersion of fine dot clusters was present. Annealing at 435°C, Fig. 1(b), produced an apparent slight decrease in cluster concentration, but annealing at 740°C, Fig. 1(C), resulted in a noticeable densification of the clusters. Finally, annealing at 900°C and 1040°C, Figs. 1(d) and (e), caused a definite decrease in cluster concentration and led to the formation of resolvable dislocation loops.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

scholarly journals A Fast Neutron Fluence Reduction Strategy for Pressure Vessel Lifetime Extension

2000 ◽  
Vol 37 (sup1) ◽  
pp. 120-124 ◽  
Author(s):  
Jong Kyung Kim ◽  
Chang Ho Shin ◽  
Bo Kyun Seo ◽  
Myung Hyun Kim ◽  
Goung Jin Lee
Keyword(s):  
Fast Neutron ◽  
Pressure Vessel ◽  
Neutron Fluence ◽  
Reduction Strategy ◽  
Lifetime Extension

scholarly journals A Method to Estimate the Fast-Neutron Fluence for the Hiroshima Atomic Bomb

1994 ◽  
Vol 63 (10) ◽  
pp. 3546-3547 ◽  
Author(s):  
Tokushi Shibata ◽  
Mineo Imamura ◽  
Seiichi Shibata ◽  
Yoshitomo Uwamino ◽  
Tohru Ohkubo ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Atomic Bomb ◽  
Neutron Fluence

3D Calculations of PWR Vessels Neutron Fluence With EFLUVE 3D Code

2013 ◽  
Author(s):  
Cécile-Aline Gosmain ◽  
Sylvain Rollet ◽  
Damien Schmitt
Keyword(s):  
Monte Carlo ◽  
Fast Neutron ◽  
Pressure Vessel ◽  
Reaction Rate ◽  
Neutron Fluence ◽  
Neutron Transport ◽  
Reaction Rates ◽  
Surveillance Program ◽  
Monte Carlo Code ◽  
Neutron Sources

In the framework of surveillance program dosimetry, the main parameter in the determination of the fracture toughness and the integrity of the reactor pressure vessel (RPV) is the fast neutron fluence on pressure vessel. Its calculated value is extrapolated using neutron transport codes from measured reaction rate value on dosimeters located on the core barrel. EDF R&D has developed a new 3D tool called EFLUVE3D based on the adjoint flux theory. This tool is able to reproduce on a given configuration the neutron flux, fast neutron fluence and reaction rate or dpa results of an exact Monte Carlo calculation with nearly the same accuracy. These EFLUVE3D calculations does the Source*Importance product which allows the calculation of the flux, the neutronic fluence (flux over 1MeV integrated on time) received at any point of the interface between the skin and the pressure vessel but also at the capsules of the pressurized water reactor vessels surveillance program and the dpa and reaction rates at different axial positions and different azimuthal positions of the vessel as well as at the surveillance capsules. Moreover, these calculations can be carried out monthly for each of the 58 reactors of the French current fleet in challenging time (less than 10mn for the total fluence and reaction rates calculations considering 14 different neutron sources of a classical power plant unit compared to more than 2 days for a classic Monte Carlo flux calculation at a given neutron source). The code needs as input: - for each reaction rate, the geometric importance matrix produced for a 3D pin by pin mesh on the basis of Green’s functions calculated by the Monte Carlo code TRIPOLI; - the neutron sources calculated on assemblies data (enrichment, position, fission fraction as a function of evolution), pin by pin power and irradiation. These last terms are based on local in-core activities measurements extrapolated to the whole core by use of the EDF core calculation scheme and a pin by pin power reconstruction methodology. This paper presents the fundamental principles of the code and its validation comparing its results to the direct Monte Carlo TRIPOLI results. Theses comparisons show a discrepancy of less than 0,5% between the two codes equivalent to the order of magnitude of the stochastic convergence of Monte Carlo results.

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