scholarly journals Origin of the drastic decrease of fusion probability in superheavy mass region

2006 ◽  
Vol 764 ◽  
pp. 149-159 ◽  
Author(s):  
Yoshihiro Aritomo ◽  
Masahisa Ohta
Keyword(s):  
Mass Region ◽  
Drastic Decrease ◽  
Fusion Probability

scholarly journals Detection capability of Migdal effect for argon and xenon nuclei with position sensitive gaseous detectors

2020 ◽  
Author(s):  
Kiseki D Nakamura ◽  
Kentaro Miuchi ◽  
Shingo Kazama ◽  
Yutaro Shoji ◽  
Masahiro Ibe ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Experimental Approach ◽  
Isotope Separation ◽  
Mass Region ◽  
Background Rate ◽  
Argon Gas ◽  
Low Mass ◽  
Position Sensitive ◽  
Set Up ◽  
Direct Dark Matter

Abstract Migdal effect is attracting interests because of the potential to enhance the sensitivities of direct dark matter searches to the low mass region. In spite of its great importance, the Migdal effect has not been experimentally observed yet. A realistic experimental approach towards the first observation of the Migdal effect in the neutron scattering was studied with Monte Carlo simulations. In this study, potential background rate was studied together with the event rate of the Migdal effect by a neutron source. It was found that a table-top sized ~ (30cm)3 position-sensitive gaseous detector filled with argon or xenon target gas can detect characteristic signatures of the Migdal effect with sufficient rates (O(102 ~ 103) events/day). A simulation result of a simple experimental set-up showed two significant background sources, namely the intrinsic neutrons and the neutron induced gamma-rays. It is found that the intrinsic neutron background rate for the argon gas is acceptable level and some future study for the reduction of the gamma-rays from the laboratory would make the observation of the Migdal effect possible. The background for the xenon gas, on the other hand, is found to be much more serious than for the argon gas. Future works on the isotope separation as well as the reduction of the gamma-rays from the detector and laboratory will be needed before the Migdal effect observation for xenon gas case.

scholarly journals Small Mass but Strong Information: Diagnostic Ions Provide Crucial Clues to Correctly Identify Histone Lysine Modifications

Proteomes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Alaa Hseiky ◽  
Marion Crespo ◽  
Sylvie Kieffer-Jaquinod ◽  
François Fenaille ◽  
Delphine Pflieger
Keyword(s):  
Amino Acid ◽  
Small Mass ◽  
Mass Region ◽  
Amino Acid Sequences ◽  
Lysine Modification ◽  
Lysine Residues ◽  
Two Factors ◽  
Low Mass ◽  
Diagnostic Ions

(1) Background: The proteomic analysis of histones constitutes a delicate task due to the combination of two factors: slight variations in the amino acid sequences of variants and the multiplicity of post-translational modifications (PTMs), particularly those occurring on lysine residues. (2) Methods: To dissect the relationship between both aspects, we carefully evaluated PTM identification on lysine 27 from histone H3 (H3K27) and the artefactual chemical modifications that may lead to erroneous PTM determination. H3K27 is a particularly interesting example because it can bear a range of PTMs and it sits nearby residues 29 and 31 that vary between H3 sequence variants. We discuss how the retention times, neutral losses and immonium/diagnostic ions observed in the MS/MS spectra of peptides bearing modified lysines detectable in the low-mass region might help validate the identification of modified sequences. (3) Results: Diagnostic ions carry key information, thereby avoiding potential mis-identifications due to either isobaric PTM combinations or isobaric amino acid-PTM combinations. This also includes cases where chemical formylation or acetylation of peptide N-termini artefactually occurs during sample processing or simply in the timeframe of LC-MS/MS analysis. Finally, in the very subtle case of positional isomers possibly corresponding to a given mass of lysine modification, the immonium and diagnostic ions may allow the identification of the in vivo structure.

Charge exchange reactions on medium and heavy mass targets at intermediate energies

2019 ◽  
Vol 35 (08) ◽  
pp. 2050045
Author(s):  
Pardeep Singh ◽  
Monika Singh ◽  
Neha Rani
Keyword(s):  
Charge Exchange ◽  
Cross Sections ◽  
Energy Charge ◽  
Impulse Approximation ◽  
Mass Region ◽  
Intermediate Energy ◽  
Exchange Reactions ◽  
Plane Wave Impulse Approximation ◽  
Text Type ◽  
Intermediate Energies

The nuclear isotopic structure can be understood easily via the intermediate-energy charge exchange reactions of (p, n) and [Formula: see text]He, [Formula: see text] type. In the current contribution, we present some results for charge exchange reactions induced by 3He on targets lying in mass region [Formula: see text] within the theoretical framework of plane wave impulse approximation (PWIA) and distorted wave impulse approximation (DWIA). Here, the recoil effects in PWIA have also been considered. Particularly, the angular distributions and the unit cross-sections have been calculated and compared with the available data. Further, the importance of inclusion of the exchange contribution in these reactions is also considered, which eventually enhance the matching with data.

EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR
Keyword(s):  
Shell Structure ◽  
Crucial Role ◽  
Field Model ◽  
Mean Field ◽  
Mass Region ◽  
The Other ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Shell Closures ◽  
Low Mass

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

Cumulative yields of stable and long-lived isotopes of tin in neutron-induced fission

1983 ◽  
Vol 61 (11) ◽  
pp. 1490-1497 ◽  
Author(s):  
K. J. R. Rosman ◽  
J. R. De Laeter ◽  
J. W. Boldeman ◽  
H. G. Thode
Keyword(s):  
Stable Isotopes ◽  
Fine Structure ◽  
Fission Product ◽  
Mass Spectrometer ◽  
Smooth Curve ◽  
Mass Region ◽  
Neutron Fission ◽  
Source Mass ◽  
Induced Fission ◽  
Fission Yields

The relative cumulative fission yields of the six stable isotopes of tin (117Sn,118Sn, 119Sn, 120Sn, 122Sn, and 124Sn) and the long-lived isotope 126Sn have been measured in the thermal and epicadium neutron fission of 233U and 235U, and the epicadium neutron fission of 238U. Nanogram-sized fission product tin samples were extracted from irradiated uranium samples and analyzed in a solid source mass spectrometer. In each case a smooth curve can be drawn through the yield points of the seven isotopes of tin. There is, therefore, no evidence of "fine structure" in the 117 ≤ A ≤ 126 portion of the symmetric mass region.

RELIABILITY ASSESSMENT OF AXIALLY COMPRESSED COMPOSITE CYLINDRICAL SHELLS WITH RANDOM IMPERFECTIONS

2011 ◽  
Vol 11 (02) ◽  
pp. 215-236 ◽  
Author(s):  
MATTEO BROGGI ◽  
ADRIANO CALVI ◽  
GERHART I. SCHUËLLER
Keyword(s):  
Mathematical Models ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Reliability Assessment ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Experimental Results ◽  
Drastic Decrease ◽  
Different Types ◽  
Probability And Statistics

Cylindrical shells under axial compression are susceptible to buckling and hence require the development of enhanced underlying mathematical models in order to accurately predict the buckling load. Imperfections of the geometry of the cylinders may cause a drastic decrease of the buckling load and give rise to the need of advanced techniques in order to consider these imperfections in a buckling analysis. A deterministic buckling analysis is based on the use of the so-called knockdown factors, which specifies the reduction of the buckling load of the perfect shell in order to account for the inherent uncertainties in the geometry. In this paper, it is shown that these knockdown factors are overly conservative and that the fields of probability and statistics provide a mathematical vehicle for realistically modeling the imperfections. Furthermore, the influence of different types of imperfection on the buckling load are examined and validated with experimental results.

Analysis of fusion–fission dynamics in superheavy mass region by pre-scission neutron multiplicities

2004 ◽  
Vol 738 ◽  
pp. 221-225 ◽  
Author(s):  
Y. Aritomo ◽  
M. Ohta ◽  
T. Materna ◽  
F. Hanappe ◽  
L. Stuttge
Keyword(s):  
Mass Region ◽  
Neutron Multiplicities

Superheavy nuclei IX: 1300 ≤ A < 1400 systems

2021 ◽  
Vol 34 (1) ◽  
pp. 54-60
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Mass Region ◽  
Binding Energies ◽  
Superheavy Nuclei ◽  
Enhanced Stability

Binding energies of nuclei are calculated in the mass region 1300 ≤ A < 1400. The calculations are performed using the adjusted Rost interaction, which suggests that a new island of stability exists for Z = 382 and in neighboring systems. Enhanced stability occurs in the <mml:math display="inline"> <mml:mrow> <mml:msubsup> <mml:mrow/> <mml:mn mathvariant="bold"> 382</mml:mn> <mml:mn mathvariant="bold">1344</mml:mn> </mml:msubsup> <mml:msub> <mml:mi mathvariant="bold">X</mml:mi> <mml:mrow> <mml:mn mathvariant="bold">962</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> system.

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