scholarly journals Gamma Ray Transitions following keV Neutron Capture in 2s-1d Shell Nuclei

1974 ◽  
Vol 27 (6) ◽  
pp. 759 ◽  
Author(s):  
MJ Kenny ◽  
PW Martin ◽  
LE Carlson ◽  
JA Biggerstaff
Keyword(s):  
Neutron Capture ◽  
Gamma Ray ◽  
Negative Parity ◽  
Mass Region ◽  
P Wave ◽  
S Wave

A Ge(Li) detector has been used to observe y-ray transitions after the capture of keV neutrons in natural samples of F, AI, Si, Sand Ar. Transitions to positive and negative parity states show that there are strong p-wave resonances as well as s-wave resonances in this mass region. The even-Z nuclei decay more by El transitions than by Ml. Odd-Z nuclei decay by strong Ml transitions.

scholarly journals keV Neutron Resonance Capture in Barium-137

1976 ◽  
Vol 29 (3) ◽  
pp. 157 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Allen ◽  
JW Boldeman ◽  
RL Macklin
Keyword(s):  
Cross Section ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
Strength Function ◽  
P Wave ◽  
Neutron Resonance ◽  
Resonance Capture ◽  
Level Spacing ◽  
S Wave ◽  
Radiative Width

The neutron capture cross section of 137Ba has been measured to high resolution (AE/E ~ o� 2 %) below En = 60 keY. Average values of resonance parameters, extracted for resonances in the range 2�7 < En < 12 keY, are as follows: s-wave level spacing <D) = 380� 70 eV; s-wave radiative width <Tv). = 80�15meV; s-wave neutron strength function 104 So = 0'57�0'2; and p-wave neutron strength function 104 S1 = 0�45�0�2. The s-wave radiative width and the s-wave neutron strength function appear to be lower for 137Ba than for the other barium isotopes.

scholarly journals Measurement of the angular distribution of γ-rays after neutron capture by 139La for a T-violation search

2019 ◽  
Vol 219 ◽  
pp. 09001 ◽  
Author(s):  
Takuya Okudaira ◽  
Hirohiko M. Shimizu ◽  
Masaaki Kitaguchi ◽  
Katsuya Hirota ◽  
Christopher C. Haddock ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Neutron Capture ◽  
Germanium Detector ◽  
P Wave ◽  
S Wave ◽  
Proton Proton ◽  
Wave Resonance ◽  
T Violation ◽  
Γ Rays ◽  
Neutron Width

Parity violating effects enhanced by up to 106 times compared to proton-proton scattering have been observed in several neutron capture induced compound nuclei. This enhancement is explained as an interference between an s-wave and a p-wave amplitude (s-p mixing). Theory predicts that this mechanism can also enhance T-violating effects. For estimation of this enhancement in a promising candidate nucleus, we measured the angular distribution of γ-rays in the (n,γ) reaction induced in a 139La target. Experiments were performed at J-PARC, using a germanium detector array at an intense neutron beam. Analysis of the observed angular dependence around the 0.74 eV p-wave resonance allowed us to determine the ratio of the partial p-wave neutron width to the total neutron width in the entrance channel of the compound nucleus. We also report our development of a 3He spin filter needed as an epithermal-neutron polarizer for the T-violation search.

scholarly journals ANALYSIS OF HIGH ENERGY K+K- PHOTOPRODUCTION ON HYDROGEN

2005 ◽  
Vol 20 (02n03) ◽  
pp. 581-583
Author(s):  
Ł. BIBRZYCKI ◽  
L. LEŚNIAK ◽  
A. P. SZCZEPANIAK
Keyword(s):  
Effective Mass ◽  
Cross Section ◽  
Good Description ◽  
Mass Range ◽  
High Energy ◽  
Mass Region ◽  
P Wave ◽  
S Wave ◽  
Mass Distributions ◽  
Scalar Resonances

We have analyzed the γp→pK+K- reaction in the K+K- effective mass region around the mass of the ϕ(1020) meson. The interference of the S-wave contribution with the P-wave has been studied. Both scalar resonances f0(980) and a0(980) have been taken into account. We obtained a good description of the available experimental data, in particular the mass distributions and the moments of the kaon angular distribution. Our calculations give values of the integrated S-wave total photoproduction cross section between 4 and 7 nb for the K+K- effective mass range around the ϕ(1020) mass and at the laboratory photon energy near 5 GeV. These numbers favor lower experimental estimates obtained at DESY.

scholarly journals Resonant Neutron Capture in 45Sc Below 100 keV

1977 ◽  
Vol 30 (6) ◽  
pp. 605 ◽  
Author(s):  
MJ Kenny ◽  
BJ Allen ◽  
RL Macklin
Keyword(s):  
Cross Section ◽  
Energy Resolution ◽  
Neutron Capture ◽  
Capture Cross Section ◽  
P Wave ◽  
Capture Cross ◽  
Neutron Capture Cross Section ◽  
S Wave ◽  
Standard Deviations

The neutron capture cross section of 45SC has been measured with 0�2 % energy resolution in the range 2�S-100keV. Many new I> 0 resonances are observed and the average s- and p-wave radiative widths and standard deviations are <Γγ>s = 0�84�0�46eV and <Γγ>p = 0�S�0�3eV. No significant correlation is observed between the reduced neutron widths and radiative widths of the s-wave resonances.

scholarly journals Resonance Neutron Capture in 138Ba and 140Ce and the Prompt Neutron Correction to ?-ray Detectors

1979 ◽  
Vol 32 (3) ◽  
pp. 213 ◽  
Author(s):  
AR de L Musgrove ◽  
BJ Alien ◽  
RL Macklin
Keyword(s):  
Cross Sections ◽  
Neutron Capture ◽  
High Energy ◽  
P Wave ◽  
Prompt Neutron ◽  
High Energy Resolution ◽  
Capture Cross ◽  
S Wave ◽  
Strength Functions ◽  
Capture Cross Sections

The neutron capture cross sections of 138Ba and 140Ce have been measured with high energy resolution between 3 and 100 keY using the capture cross section facility at the 40 m station of the Oak Ridge Electron Linear Accelerator. The average s-wave level spacings are <D)s = 6�3 � 1 �7 and 3�2 � 0�8 keY for 138Ba and 140Ce respectively. The deduced s-wave neutron strength functions are 104So = 1�0�0�4 and 1�54�0�53 respectively, and the average s-wave radiative widths are <r,)s = 55�20 and 35�9meY. The p-wave neutron strength functions are 104S1 ~ 0�03 and 0�32�0�12 respectively. The average 30 keY Maxwellian capture cross sections are 3�9�0�8mb for 138Ba and 7�7 � 0�9 mb for 140Ce. A more rigorous treatment of the prompt neutron correction for l'-ray detectors is described, and it is shown that previously published results for 138Ba have underestimated this correction. The 140Ce data provide excellent corroboration for the calculated magnitude and time dependence of the prompt neutron correction.

DESCRIPTION OF SU(3) S-WAVE AND P-WAVE BARYONS

2003 ◽  
Vol 18 (02n06) ◽  
pp. 362-365
Author(s):  
MIKITO FURUICHI ◽  
KIYOTAKA SHIMIZU ◽  
Sachiko Takeuchi
Keyword(s):  
Quark Model ◽  
Excited States ◽  
Negative Parity ◽  
Nucleon Resonance ◽  
P Wave ◽  
Meson Exchange ◽  
Exchange Potential ◽  
Chiral Quark Model ◽  
S Wave ◽  
Quark System

We investigate the structure of the SU(3) octet and decuplet baryons employing a constituent chiral quark model. We study the ground, s-wave and p-wave excited states of the three-quark system with many range gaussian bases. The method, which we employ here, is shown to work quite well in describing the structure of the SU(3) s-wave and p-wave baryons. It is found that the mass differences between positive and negative parity states are well reproduced. It is also found that the pseudoscalar (ps) meson exchange potential plays a very important role in describing the mass of the nucleon resonance N*(1440) (roper). We also discuss how the semirelativistic approach works in the chiral quark model, and how to treat the potential terms in the semirelativistic approach.

scholarly journals Post-collisional mantle delamination in the Dinarides implied from staircases of Oligo-Miocene uplifted marine terraces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philipp Balling ◽  
Christoph Grützner ◽  
Bruno Tomljenović ◽  
Wim Spakman ◽  
Kamil Ustaszewski
Keyword(s):  
Balkan Peninsula ◽  
Receiver Functions ◽  
P Wave ◽  
S Wave ◽  
Slab Geometry ◽  
Surface Uplift ◽  
River Incision ◽  
Marine Terraces ◽  
Convergence System ◽  
Internal Dinarides

AbstractThe Dinarides fold-thrust belt on the Balkan Peninsula resulted from convergence between the Adriatic and Eurasian plates since Mid-Jurassic times. Under the Dinarides, S-wave receiver functions, P-wave tomographic models, and shear-wave splitting data show anomalously thin lithosphere overlying a short down-flexed slab geometry. This geometry suggests a delamination of Adriatic lithosphere. Here, we link the evolution of this continental convergence system to hitherto unreported sets of extensively uplifted Oligocene–Miocene (28–17 Ma) marine terraces preserved at elevations of up to 600 m along the Dinaric coastal range. River incision on either side of the Mediterranean-Black Sea drainage divide is comparable to the amounts of terrace uplift. The preservation of the uplifted terraces implies that the most External Dinarides did not experience substantial deformation other than surface uplift in the Neogene. These observations and the contemporaneous emplacement of igneous rocks (33–22 Ma) in the internal Dinarides suggest that the Oligo-Miocene orogen-wide uplift was driven by post-break-off delamination of the Adriatic lithospheric mantle, this was followed by isostatic readjustment of the remaining crust. Our study details how lithospheric delamination exerts an important control on crustal deformation and that its crustal signature and geomorphic imprint can be preserved for millions of years.

scholarly journals S-wave experiments for the exploration of a deep geothermal carbonate reservoir in the German Molasse Basin

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Britta Wawerzinek ◽  
Hermann Buness ◽  
Hartwig von Hartmann ◽  
David C. Tanner
Keyword(s):  
Upper Jurassic ◽  
Carbonate Reservoir ◽  
P Wave ◽  
Seismic Survey ◽  
Seismic Exploration ◽  
Molasse Basin ◽  
S Wave ◽  
Induced Earthquakes ◽  
Conversion Point ◽  
Facies Classification

AbstractThere are many successful geothermal projects that exploit the Upper Jurassic aquifer at 2–3 km depth in the German Molasse Basin. However, up to now, only P-wave seismic exploration has been carried out. In an experiment in the Greater Munich area, we recorded S-waves that were generated by the conventional P-wave seismic survey, using 3C receivers. From this, we built a 3D volume of P- to S-converted (PS) waves using the asymptotic conversion point approach. By combining the P-volume and the resulting PS-seismic volume, we were able to derive the spatial distribution of the vp/vs ratio of both the Molasse overburden and the Upper Jurassic reservoir. We found that the vp/vs ratios for the Molasse units range from 2.0 to 2.3 with a median of 2.15, which is much higher than previously assumed. This raises the depth of hypocenters of induced earthquakes in surrounding geothermal wells. The vp/vs ratios found in the Upper Jurassic vary laterally between 1.5 and 2.2. Since no boreholes are available for verification, we test our results against an independently derived facies classification of the conventional 3D seismic volume and found it correlates well. Furthermore, we see that low vp/vs ratios correlate with high vp and vs velocities. We interpret the latter as dolomitized rocks, which are connected with enhanced permeability in the reservoir. We conclude that 3C registration of conventional P-wave surveys is worthwhile.

Inverse design of layered periodic wave barriers based on deep learning

2021 ◽  
pp. 146442072110168
Author(s):  
Chen-Xu Liu ◽  
Gui-Lan Yu
Keyword(s):  
Deep Learning ◽  
Activation Function ◽  
Periodic Wave ◽  
P Wave ◽  
Soil Parameters ◽  
S Wave ◽  
Output Frequency ◽  
Great Generality ◽  
Typical Range ◽  
Deep Learning Model

This study presents an approach based on deep learning to design layered periodic wave barriers with consideration of typical range of soil parameters. Three cases are considered where P wave and S wave exist separately or simultaneously. The deep learning model is composed of an autoencoder with a pretrained decoder which has three branches to output frequency attenuation domains for three different cases. A periodic activation function is used to improve the design accuracy, and condition variables are applied in the code layer of the autoencoder to meet the requirements of practical multi working conditions. Forty thousand sets of data are generated to train, validate, and test the model, and the designed results are highly consistent with the targets. The presented approach has great generality, feasibility, rapidity, and accuracy on designing layered periodic wave barriers which exhibit good performance in wave suppression in targeted frequency range.

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