scholarly journals Underground Nuclear Astrophysics in China

2015 ◽  
Vol 11 (A29A) ◽  
pp. 333-336
Author(s):  
Liu WeiPing ◽  
Keyword(s):  
Stellar Evolution ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
High Current ◽  
Low Background ◽  
Set Up ◽  
Ecr Source

AbstractUnderground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors will be set up. We plan to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies, such as 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O.

Underground nuclear astrophysics experiment JUNA in China

2019 ◽  
Vol 15 (S350) ◽  
pp. 313-320
Author(s):  
LIU WeiPing ◽  
LI ZhiHong ◽  
HE JiangJun ◽  
TANG XiaoDong ◽  
LIAN Gang ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
High Current ◽  
Low Background ◽  
Direct Measurements ◽  
Ecr Source

AbstractUnderground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

scholarly journals Felsenkeller 5 MV underground accelerator: Towards the Holy Grail of Nuclear Astrophysics 12C(α, γ)16O

2018 ◽  
Vol 178 ◽  
pp. 01008 ◽  
Author(s):  
Daniel Bemmerer ◽  
Thomas E. Cowan ◽  
Marcel Grieger ◽  
Sebastian Hammer ◽  
Thomas Hensel ◽  
...  
Keyword(s):  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Ion Beams ◽  
High Current ◽  
Construction Work ◽  
Present Contribution ◽  
Low Background ◽  
The Status ◽  
Carbon Burning ◽  
Pelletron Accelerator

Low-background experiments with stable ion beams are an important tool for putting the model of stellar hydrogen, helium, and carbon burning on a solid experimental foundation. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso, using a 0.4 MV accelerator. The present contribution reviews the status of the project for a higher-energy underground accelerator in Felsenkeller, Germany. Results from γ-ray, neutron, and muon background measurements in the Felsenkeller underground site in Dresden, Germany, show that the background conditions are satisfactory. Two tunnels of the Felsenkeller site have recently been refurbished for the installation of a 5MV high-current Pelletron accelerator. Civil construction work has completed in March 2018. The accelerator will provide intense, 50 μA, beams of 1H+, 4He+, and 12C+ ions, enabling research on astrophysically relevant nuclear reactions with unprecedented sensitivity.

scholarly journals Global predictions for astrophysics applications

2020 ◽  
Vol 13 ◽  
pp. 18
Author(s):  
P. Demetriou
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Reaction Network ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Hartree Fock ◽  
Microscopic Models ◽  
The Stability

Nuclear reaction rates play a crucial role in nuclear astrophysics. In the last decades there has been an enormous effort to measure reaction cross sections and extensive experimental databases have been compiled as a result. In spite of these efforts, most nuclear reaction network calculations still have to rely on theoretical predic- tions of experimentally unknown rates. In particular, in astrophysics applications such as the s-, r- and p-process nucleosynthesis involving a large number of nuclei and nuclear reactions (thousands). Moreover, most of the ingredients of the cal- culations of reaction rates have to be extrapolated to energy and/or mass regions that cannot be explored experimentally. For this reason it is important to develop global microscopic or semi-microscopic models of nuclear properties that give an accurate description of existing data and are reliable for predictions far away from the stability line. The need for more microscopic input parameters has led to new devel- opments within the Hartree-Fock-Bogoliubov method, some of which are presented in this paper.

scholarly journals Nuclear Reactions in the Later Stage of the Stellar Evolution

1956 ◽  
Vol 16 (4) ◽  
pp. 389-415 ◽  
Author(s):  
Kimiko Nakagawa ◽  
Takashi Ohmura ◽  
Hisao Takebe ◽  
Shinya Obi
Keyword(s):  
Stellar Evolution ◽  
Nuclear Reactions

scholarly journals Low-background, digital gamma-ray spectrometer with BEGe detector and active shield: commissioning, optimisation and software development

2019 ◽  
Vol 322 (3) ◽  
pp. 1311-1321
Author(s):  
Krzysztof Gorzkiewicz ◽  
Jerzy Wojciech Mietelski ◽  
Renata Kierepko ◽  
Kamil Brudecki
Keyword(s):  
Gamma Ray ◽  
Germanium Detector ◽  
Low Background ◽  
Gamma Ray Spectrometer ◽  
Annihilation Peak ◽  
The Mean ◽  
Plastic Scintillators ◽  
Set Up ◽  
Active Shield ◽  
Broad Energy

Abstract This paper presents results of the development process of low-background, digital gamma-rays spectrometer equipped with Broad Energy Germanium detector (CANBERRA BE5030), multi-layer passive shield and cosmic veto system that consists of five plastic scintillators (SCIONIX EJ-200). Data acquisition is performed using digitizer CAEN DT5725 with CoMPASS software. Output data analysis is carried out with purposely written and developed code VETO. On the basis of conducted tests, acquisition parameters were set up and tuned as well as time delays between all detectors were established. As a result of the configuration process, the mean background counts reduction of 64% in the whole spectrum and 65% in annihilation peak were achieved. This procedure allowed diminishing detection limits of selected isotopes 37% on average.

scholarly journals Physical mechanisms of mixing in stellar interiors

1984 ◽  
Vol 105 ◽  
pp. 491-512
Author(s):  
Evry Schatzman
Keyword(s):  
Diffusion Equation ◽  
Stellar Evolution ◽  
Turbulent Mixing ◽  
Nuclear Reactions ◽  
Chemical Elements ◽  
Solar Neutrinos ◽  
Stellar Structure ◽  
Physical Mechanisms ◽  
Nitrogen Abundance ◽  
Stellar Interiors

The different mechanisms by which mixing can take place in stellar interiors are considered : the classical Rayleigh-Benard instability with penetrative convection and over-shooting, semi-convection, gravitationnal and radiative settling, turbulent mixing. The latter mechanism is thoroughly described, from the driving force of turbulent mixing to its influence on stellar structure, stellar evolution and the analysis of the corresponding observationnal data.Turbulent mixing has to be considered each time the building up of a concentration gradient takes place, either by gravitationnal or radiative settling or by nuclear reactions. Turbulent mixing, as a first approximation, can be described by an isotropic diffusion coefficient. The process is then governed by a diffusion equation. The behaviour of the solution of the diffusion equation needs some explanation in order to be well understood.A number of examples concerning surface abundances of chemical elements are given (3He, 7Li, Be, 12C, 13C, 14N), as well as a discussion of the solar neutrinos problem.The building up of a µ-barrier, which stops the turbulence allows stellar evolution towards the giant branch and explains nitrogen abundance at the surface of giants of the first ascending branch.Turbulent mixing is also of some importance for the transfer of angular momentum and has to be taken into account for explaining the abundance of the elements in Wolf-Rayet stars.

scholarly journals Possibility for nuclear physics study based on Pelletron accelerator at Hanoi, Vietnam

2019 ◽  
Vol 206 ◽  
pp. 08004
Author(s):  
Cuong Phan Viet ◽  
Anh Le Tuan ◽  
Chung Le Xuan ◽  
Ha Nguyen Hong ◽  
Thao Ho Thi ◽  
...  
Keyword(s):  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Simulation Results ◽  
Set Up ◽  
Pelletron Accelerator

In this report, overview of the new installed Pelletron 5SDH-2 accelerator at Hanoi University of Science, Vietnam and possibilities for performing astrophysics-related nuclear reactions based on this accelerator will be described. In addition to that, some preliminary simulation results for designing and optimizing the experimental set-up in studying reactions 10B(α, p)13C with projectile energies in the Gamow-window will be shown.

scholarly journals 26Mg target for nuclear astrophysics measurements

2018 ◽  
Vol 184 ◽  
pp. 02014
Author(s):  
I. Siváček ◽  
J. Mrázek ◽  
V. Kroha ◽  
V. Burjan ◽  
V. Glagolev ◽  
...  
Keyword(s):  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Asymptotic Normalization ◽  
Physics Institute ◽  
Astrophysical Interest ◽  
Target Composition ◽  
Czech Academy ◽  
Academy Of Sciences ◽  
Nuclear Physics Institute

Two nuclear reactions of astrophysical interest, 26Mg(3He,d)27Al and 26Mg(d,p)27Mg, were measured for extraction of the Asymptotic Normalization Coefficients. Investigation of the target composition is presented, as well as the effects that showed up during analysis of the in-beam data obtained on CANAM accelerators in the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS).

scholarly journals Role of nuclear reactions on stellar evolution of intermediate-mass stars

2018 ◽  
Vol 940 ◽  
pp. 012050
Author(s):  
H Möller ◽  
S Jones ◽  
T Fischer ◽  
G Martínez-Pinedo
Keyword(s):  
Stellar Evolution ◽  
Nuclear Reactions ◽  
Intermediate Mass ◽  
Intermediate Mass Stars
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