Analysis of complete, incomplete and total fusion data of 9Be +169Tm, 187Re, 209Bi reactions

2016 ◽  
Vol 31 (37) ◽  
pp. 1650201 ◽  
Author(s):  
Rajesh Kharab ◽  
Rajiv Chahal ◽  
Rajiv Kumar
Keyword(s):  
Cross Sections ◽  
Incident Beam ◽  
Incomplete Fusion ◽  
Selection Function ◽  
Complete Fusion ◽  
Relative Contribution ◽  
Fusion Data ◽  
Wong’S Formula ◽  
Incident Beam Energy ◽  
Total Fusion

We have analyzed the incomplete fusion (ICF), complete fusion (CF) and total fusion (TF) excitation functions for reactions induced by [Formula: see text] on [Formula: see text], [Formula: see text] and [Formula: see text] targets at near barrier energies using Wong’s formula in conjunction with the energy dependent Woods–Saxon potential. A phenomenological selection function is proposed to separate out the contribution of ICF and CF cross-sections in TF cross-section. The variation of relative contribution of ICF and CF in TF with respect to incident beam energy is very well reproduced through this approach.

Fragmentation analysis of 105Ag∗ nucleus governed via complete and incomplete fusion channels at Ec.m. = 89MeV

2020 ◽  
Vol 35 (12) ◽  
pp. 2050084
Author(s):  
Ishita Sharma ◽  
Manoj K. Sharma
Keyword(s):  
Cross Sections ◽  
Center Of Mass ◽  
Incident Beam ◽  
Heavy Ion ◽  
Incomplete Fusion ◽  
Cluster Decay ◽  
Complete Fusion ◽  
Center Of Mass Energy ◽  
Complete And Incomplete Fusion ◽  
Incident Beam Energy

A systematic study of dynamical aspects associated with heavy-ion-induced [Formula: see text] reaction is carried out at center-of-mass energy [Formula: see text] MeV. The complete fusion (CF) and incomplete fusion (ICF) contributions are estimated by using the dynamical cluster-decay model (DCM). The incomplete fusion component is examined by normalizing the incident beam energy for each of the breakup fragment. The fusion evaporation cross-sections that emerged from CF and ICF channels are duly addressed using the optimized value of neck-length parameter [Formula: see text]. Further, the mass yield of compound nuclei (CN) formed in the CF and ICF processes is analyzed with respect to angular momentum [Formula: see text] values. The DCM-based calculations indicate the possible contribution of deep inelastic collision (DIC) in the decay of [Formula: see text] at higher [Formula: see text] values, and DIC cross-sections are predicted which call for future validation.

Projectile breakup effects in the fusion dynamics of 6,7Li +144,152Sm reactions around Coulomb barrier

2020 ◽  
Vol 29 (05) ◽  
pp. 2050029
Author(s):  
Manjeet Singh Gautam ◽  
Sukhvinder Duhan ◽  
Rishi Pal Chahal ◽  
Hitender Khatri ◽  
Suman B. Kuhar ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Coulomb Barrier ◽  
Incomplete Fusion ◽  
Complete Fusion ◽  
Cross Section Data ◽  
Suppression Factor ◽  
Model Calculations ◽  
Section Data ◽  
Breakup Channel

This work emphasized the role of the projectile breakup channel by studying the complete fusion (CF) and incomplete fusion (ICF) dynamics of [Formula: see text] reactions. The theoretical calculations for the chosen reactions have been done by opting for the coupled channel approach and the energy dependent Woods–Saxon potential (EDWSP) model. The below barrier fusion enhancements of the studied reactions are reasonably addressed by the outcomes of the adopted models, which in turn can be attributed to the couplings of nuclear structure degrees of freedom of the collision partners to their relative motion. In contrast, at above barrier energies, the CF cross-section data of the chosen reactions are found to be suppressed significantly when compared with the predictions made by using the present models. Interestingly, the fusion suppression factors of the given reactions can be minimized considerably with respect to the reported value when it is analyzed within the framework of the EDWSP model. For instance, in case of [Formula: see text] ([Formula: see text] reaction, the magnitude of fusion suppression factor is minimized up to 7% (13%) relative to the reported value whereas for [Formula: see text] ([Formula: see text] reaction, the fusion suppression factor is found to be less by 7% (8%) with reference to the reported value. Such suppression effects can be correlated with the low breakup threshold of alpha breakup channel associated with the loosely bound projectile. The projectiles being weakly bound systems split into two charged fragments and either of the breakup components is absorbed by the target resulting in the reduction of incoming flux going into fusion channel. The flux lost from the CF channel appears in the form of ICF yields. For [Formula: see text], total fusion (TF) cross-sections that are sum of CF and ICF cross-sections are also analyzed in conjunction with the EDWSP model and thus reasonably explained by the model calculations. In order to identify the ICF contribution, the ratio of ICF/TF cross-section data of [Formula: see text] reaction has been examined and thus properly addressed by using the EDWSP model. The presence of ICF component in TF cross-section clearly pointed out the breakup of projectile due to its loosely bound nature prior to the Coulomb barrier. Although ICF data of other systems are not available in the literature, a similar behavior is expected for ICF and TF data for [Formula: see text] and [Formula: see text] reactions.

Mapping the Structure of a Hydrated Polymer Blend Using Energy-Loss Spectroscopy in the Cryo-STEM

2004 ◽  
Vol 839 ◽  
Author(s):  
Alioscka Sousa ◽  
Abdelaziz Aitouchen ◽  
Matthew Libera
Keyword(s):  
Spatial Distribution ◽  
Energy Loss ◽  
Polymer Blend ◽  
Cross Sections ◽  
Incident Beam ◽  
Two Phase ◽  
Electron Dose ◽  
Spatially Resolved ◽  
Incident Beam Energy ◽  
Scattering Cross Sections

ABSTRACTWe use electron energy-loss spectroscopy (EELS) in the cryo-STEM to determine the spatial distribution of water in a model frozen-hydrated two-phase polymer blend composed of hydrophilic poly(vinylpyrrolidone) (PVP) and hydrophobic poly(styrene) (PS). We demonstrate that it is possible to directly correlate the water spatial distribution with variations in the underlying polymer morphology. HAADF-STEM imaging of both dry and frozen-hydrated specimens shows weak contrast between the polymer phases but gives no information regarding the composition of these phases and no indication of where water might be localized. Spatially-resolved EELS spectra collected at 100 nm pixel size show that this system is composed of discrete PVP-rich domains dispersed in a continuous PS-rich matrix. The PVP-rich domains were found to be hydrated up to a level of ∼ 23 wt%. We have made our compositional maps fully quantitative, given as mass-fraction maps, by measuring the total inelastic scattering cross-sections per unit mass of water, PVP and PS. This is an important quantity which we have determined for an incident beam energy of 200 keV. Hydrated PVP gives rise to hydrogen evolution when irradiated above an electron dose of 1500 e/nm2 as evidenced from changes in the 13 eV region, and this effect gives rise to dose-limited resolution in these experiments.

INVESTIGATION OF INCOMPLETE FUSION IN 19F+159Tb REACTION AT BEAM ENERGY OF ~ 5 MeV/NUCLEON

2011 ◽  
Vol 20 (11) ◽  
pp. 2305-2315 ◽  
Author(s):  
AMIT KUMAR ◽  
K. SUDARSHAN ◽  
SUPARNA SODAYE ◽  
R. TRIPATHI ◽  
P. K. PUJARI
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Significant Contribution ◽  
Gamma Ray ◽  
Incomplete Fusion ◽  
Gamma Ray Spectrometry ◽  
Complete Fusion ◽  
Rule Model ◽  
Evaporation Residues ◽  
Critical Angular Momentum

Formation cross-sections of evaporation residues have been measured in 19 F +159 Tb reaction at E lab =83, 88, 93, 98 and 103 MeV using recoil catcher technique followed by off-line gamma-ray spectrometry. Significant contribution from incomplete fusion has been observed at these low beam energies indicating the contribution to incomplete fusion from collision trajectories with angular momentum (l) less than the critical angular momentum for complete fusion (l cr (CF)) . Incomplete fusion cross-sections could be explained using a modified sum-rule model which allows effective competition from incomplete fusion for collision trajectories with l<l cr (CF) .

Coupled channel analysis of fusion excitation function for 9Be+64Zn system at near and above barrier energies

2020 ◽  
Vol 35 (31) ◽  
pp. 2050257
Author(s):  
Chetna ◽  
Pardeep Singh ◽  
Rajesh Kharab
Keyword(s):  
Excitation Function ◽  
Neutron Capture ◽  
Incomplete Fusion ◽  
Complete Fusion ◽  
Breakup Threshold ◽  
Body System ◽  
Weakly Bound ◽  
Channel Analysis ◽  
Coupled Channel ◽  
Total Fusion

We have calculated excitation functions of incomplete fusion, complete fusion and total fusion processes for [Formula: see text] system at near and above barrier energies. In particular, breakup effects of weakly bound projectile [Formula: see text], which has been considered as a two body system [Formula: see text] with a breakup threshold of 1.667 MeV, have been studied. The calculations are performed by using the code FRESCO, which is based on Continuum Discretized Coupled Channel (CDCC) approach. The present analysis of the total fusion excitation function for the system [Formula: see text] shows that it is suppressed at above barrier energies and enhanced at sub barrier energies when the breakup effects are taken into account. In addition, the comparison of the probabilities of incomplete fusion from neutron capture and that from alpha capture shows the dominance of former over later.

scholarly journals Complete and incomplete fusion in 9Be+124Sn system

2011 ◽  
Vol 1 (1) ◽  
pp. 131-134
Author(s):  
V. V. Parkar ◽  
R. Palit ◽  
Sushil K. Sharma ◽  
B. S. Naidu ◽  
P. K. Joshi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Coulomb Barrier ◽  
Gamma Ray ◽  
Detection Technique ◽  
Incomplete Fusion ◽  
Complete Fusion ◽  
On Line ◽  
Complete And Incomplete Fusion

AbstractComplete and incomplete fusion cross-sections for the 9Be+124Sn system have been measured around the Coulomb barrier energies (ElabC.B=28 MeV) using the on-line gamma ray detection technique. The complete fusion cross-sections of this system have been compared with the two stable projectiles on the same 124Sn target to provide information on the projectile dependence. The brief comparison of the present 9Be+124Sn data with a comprehensive and recent study of the neighbouring system 9Be+144Sm is also given.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

LACBED with Quantitative Anomalous Absorption Corrections

1990 ◽  
Vol 48 (2) ◽  
pp. 528-529
Author(s):  
C.J. Rossouw ◽  
L.J. Allen ◽  
P.R. Miller
Keyword(s):  
Momentum Transfer ◽  
Scattering Amplitude ◽  
Incident Beam ◽  
Waller Factor ◽  
Beam Momentum ◽  
Anomalous Absorption ◽  
Quantitative Calculation ◽  
Ewald Sphere ◽  
Image Position ◽  
Incident Beam Energy

An Einstein model for thermal diffuse scattering (TDS) has enabled quantitative calculation of the absorptive potential V'(r). This allows anomalous absorption to be accounted for in LACBED contrast. Fourier coefficients Vg-h of the absorptive component from each atom α are calculated from integrals of the formwhere fα is the scattering amplitude and M(Q) the Debye-Waller factor. Integration over the Ewald sphere (dΩ) requires the momentum transfer q to have values up to 2ko (the incident beam momentum). Dynamical ‘dechannelling’ is accounted for by the terms g ≠ h. The crystal absorptive potential is obtained by coherently summing over these atomic absorptive potentials within the unit cell. Unlike the elastic potential, the absorptive potential is a strong function of incident beam energy Eo, since the range of momentum transfer q and associated solid angles dΩ change with the Ewald sphere radius.Fig. 1 shows a LACBED pattern of the zeroth order beam from Si aligned along a <001> zone axis.

Sign in / Sign up

Export Citation Format

Share Document