The d + d reactions at low energies II. Comparison of angular distributions of outgoing nucleon polarizations for the charge symmetric reactions2H(d,p)3H and2H(d,n)3He

1987 ◽  
Vol 37 (6) ◽  
pp. 694-697
Author(s):  
P. Kozma
Keyword(s):  
Angular Distributions ◽  
Outgoing Nucleon ◽  
Low Energies

scholarly journals Precision measurements on oxygen formation in stellar helium burning with gamma-ray beams and a Time Projection Chamber

2021 ◽  
Author(s):  
Robin Smith ◽  
Moshe Gai ◽  
Sarah Stern ◽  
Deran Schweitzer ◽  
Mohammad Ahmed
Keyword(s):  
Time Projection Chamber ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Angular Distributions ◽  
Helium Burning ◽  
Low Energies ◽  
Important Input ◽  
Novel Method ◽  
Time Projection ◽  
First Time

Abstract Stellar Evolution theory relies on our knowledge of nuclear reactions, with the carbon/oxygen (C/O) ratio, at the end of helium burning, being the single most important input. However, the C/O ratio is still not known with sufficient accuracy, due to large uncertainties in the cross section for the fusion of helium with 12C to form 16O, denoted as the 12C(α,γ)16O reaction. We present initial results at moderately low energies using a novel method, which is significantly different from the experimental efforts of the past four decades. Precise angular distributions of the 12C(α,γ)16O reaction were obtained by measuring the inverse 16O(γ,α)12C reaction with gamma-beams and a Time Projection Chamber detector. These allowed us to measure, for the first time, the interference angle of the l = 1 and 2 partial waves contributing to this reaction (φ12), which agrees with predictions based on the unitarity of the scattering matrix.

scholarly journals On the Experimental Investigation of the Angular Distributions in the Reaction 112Cd(p,γ)113In

2019 ◽  
Vol 26 ◽  
pp. 188
Author(s):  
A. Zyriliou ◽  
A. Khaliel ◽  
T. J. Mertzimekis
Keyword(s):  
Cross Sections ◽  
Nuclear Physics ◽  
Gamma Ray ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Special Focus ◽  
Tandem Accelerator ◽  
Section Data ◽  
Hpge Detectors ◽  
Low Energies

Some of the mid–weight nuclei lie in the region of the isotopic chart where the astrophysical p-process has a prominent role in the nucleosynthetic scenarios. Experimentally deduced reaction cross section data can provide stringent tests for the astrophysical models, especially at low energies. In this framework, the reaction 112Cd(p,γ)113In has been studied experimentally at four proton beam energies 2.8 ≤ Ep≤ 3.4 MeV, partly inside the astrophysically interesting Gamow window. Proton beams were provided by the 5.5 MV T11 Van de Graaff Tandem Accelerator of the Institute of Nuclear Physics of the National Center for Scientific Research (NCSR) “Demokritos”. In–beam spectroscopy was carried out with an array of four HPGe detectors sitting on a rotating table. In total, eight (8) different angles were used to record gamma–ray spectra. Special focus was given on constructing the angular distribution of each gamma–ray feeding the ground state of 113In directly, so as to determine the reaction cross sections from the in–beam data, exclusively. The resulting cross sections were compared to Hauser–Feshbach calculations using the code TALYS v1.9.

scholarly journals Pairing effects on neutron elastic scattering at low-energies

2020 ◽  
Vol 129 (1B) ◽  
pp. 57-61
Author(s):  
N. Hoang Tung ◽  
T. Dieu Thuy ◽  
D. Quang Tam ◽  
T. Ngoc Quynh Tran ◽  
T. V. Nhan Hao
Keyword(s):  
Elastic Scattering ◽  
Ground State ◽  
Open Shell ◽  
Angular Distributions ◽  
Microscopic Calculation ◽  
Energy Neutron ◽  
Low Energies ◽  
Pairing Correlations ◽  
Vibration Coupling ◽  
First Time

For the first time, a realistic microscopic calculation for low-energy neutron-nucleus elastic scattering off open-shell nuclei is carried out within the framework of particle-vibration coupling (PVC). In this study, the pairing correlations of the ground state are taken into account. The dependence of the angular distributions on the pairing gaps is discussed.

scholarly journals THE DYNAMICAL DIPOLE RADIATION IN DISSIPATIVE COLLISIONS WITH EXOTIC BEAMS

2008 ◽  
Vol 17 (01) ◽  
pp. 110-119 ◽  
Author(s):  
M. DI TORO ◽  
M. COLONNA ◽  
C. RIZZO ◽  
V. BARAN
Keyword(s):  
Nuclear Interaction ◽  
Heavy Ion ◽  
Angular Distributions ◽  
Radioactive Beams ◽  
Dipole Radiation ◽  
Nuclear Equation Of State ◽  
Ion Collisions ◽  
Low Energies ◽  
Isovector Part ◽  
Exotic Beams

Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this work we present a selection of reaction observables in dissipative collisions particularly sensitive to the isovector part of the interaction, i.e. to the symmetry term of the nuclear Equation of State (EoS). At low energies the behavior of the symmetry energy around saturation influences dissipation and fragment production mechanisms. We will first discuss the recently observed Dynamical Dipole Radiation, due to a collective neutron-proton oscillation during the charge equilibration in fusion and deep-inelastic collisions. We will review in detail all the main properties, yield, spectrum, damping and angular distributions, revealing important isospin effects. Reactions induced by unstable 132Sn beams appear to be very promising tools to test the sub-saturation Isovector EoS. Predictions are also presented for deep-inelastic and fragmentation collisions induced by neutron rich projectiles. The importance of studying violent collisions with radioactive beams at low and Fermi energies is finally stressed.

Angular distributions of charge exchange collisions at very low energies

1993 ◽  
Vol 79 (1-4) ◽  
pp. 52-54
Author(s):  
N. Keller ◽  
R.D. Miller ◽  
M. Westerlind ◽  
L.R. Andersson ◽  
S.B. Elston ◽  
...  
Keyword(s):  
Charge Exchange ◽  
Angular Distributions ◽  
Low Energies

scholarly journals Pairing effects on neutron elastic scattering at low-energies

2020 ◽  
Vol 129 (1B) ◽  
Author(s):  
Trần Viết Nhân Hào ◽  
Hoàng Tùng Nguyễn ◽  
Diệu Thùy Trần ◽  
Quang Tâm Đỗ ◽  
Ngọc Quỳnh Trân Trần ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Ground State ◽  
Open Shell ◽  
Angular Distributions ◽  
Microscopic Calculation ◽  
Energy Neutron ◽  
Low Energies ◽  
Pairing Correlations ◽  
Vibration Coupling ◽  
First Time

For the first time, a realistic microscopic calculation for low-energy neutron-nucleus elastic scattering off open-shell nuclei is carried out within the framework of particle-vibration coupling (PVC). In this study, the pairing correlations of the ground state are taken into account. The dependence of the angular distributions on the pairing gaps have been discussed.

scholarly journals Analysis of Angular Distributions of Heavy-ion Transfer Reactions

1980 ◽  
Vol 33 (6) ◽  
pp. 965
Author(s):  
CBO Mohr
Keyword(s):  
Elastic Scattering ◽  
Heavy Ions ◽  
Heavy Ion ◽  
Critical Value ◽  
Transfer Reactions ◽  
Angular Distributions ◽  
Ion Transfer ◽  
S Matrix ◽  
Low Energies ◽  
Nuclear Phases

Proceeding as in our earlier analysis of elastic scattering, but with a form for the S matrix appropriate for transfer, peaked at the critical value Ie and with width parameter .d, it is shown how to analyse the angular distribution of transfer reactions of heavy ions to obtain.d. The effect of the nuclear phases is found not to be of such fundamental importance as in elastic scattering. Analysis of theexperimental data reveals an increase of.d with nuclear size especially at low energies, but an increase of nuclear penetration for transfer collisions of the lightest nuclei. The circumstances in which strong coupling might occur between elastic scattering and transfer are examined.

scholarly journals Angular distributions of γ rays from theLi7(p,γ) reaction at low energies

1996 ◽  
Vol 53 (3) ◽  
pp. 1273-1277 ◽  
Author(s):  
K. I. Hahn ◽  
C. R. Brune ◽  
R. W. Kavanagh
Keyword(s):  
Angular Distributions ◽  
Low Energies ◽  
Γ Rays

Fresnel interference in point-projection imaging of purple membrane

1995 ◽  
Vol 53 ◽  
pp. 846-847
Author(s):  
X. Zhang ◽  
J. Spence ◽  
W. Qian ◽  
D. Taylor ◽  
K. Taylor
Keyword(s):  
Detection Efficiency ◽  
Mean Free Path ◽  
Purple Membrane ◽  
Unit Cell Dimension ◽  
Experimental Point ◽  
Membrane Thickness ◽  
Low Energies ◽  
Channel Plate ◽  
Point Projection ◽  
Inelastic Mean Free Path

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

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