Mass measurement of light neutron-rich fragmentation products

doi:10.1016/0370-2693(86)90171-1

Physics Letters B

Volume 176, Issues 3–4, 28 August 1986, Pages 317-321

https://doi.org/10.1016/0370-2693(86)90171-1 Get rights and content

Abstract

Direct mass measurements of nitrogen, oxygen and fluorine neutron-rich isotopes were performed using the GANIL facility and the new magnetic spectrometer SPEG. A 116 m flight path allowed to achieve an accuracy down to a few 10⁻⁵.

References (11)

M. Langevin
Phys. Lett. B
(1985)
D. Guillemaud-Mueller
Z. Phys.
(1985)
G. Audi
A.M. Wapstra et al.
The 1983 Atomic Mass Evaluation
Nucl. Phys.
(1985)
J.A. Musser et al.
Phys. Rev. Lett.
(1984)
F. Pougheon
P. Birien and S. Valero, Note CEA No....

There are more references available in the full text version of this article.

Cited by (72)

Nuclear Data Sheets for A=24
2022, Nuclear Data Sheets
Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for ²⁴N, ²⁴O, ²⁴F, ²⁴Ne, ²⁴Na, ²⁴Mg, ²⁴Al, and ²⁴Si. This evaluation for A=24 supersedes the earlier one by R. B. Firestone (2007Fi14).
Highlights of this evaluation are the following:
In ²⁴O, the 7.4- and 7.65-MeV groups reported in ¹H(²⁴O,p′) (2012Ts03) and ⁹Be(²⁶F,nX) (2011Ho05), respectively, are considered as separate states in this evaluation, since the former one was observed to decay by only one neutron emission to ²³O, while the latter one by two sequential neutrons to ²²O. Based on assigned configurations, the 7.4- and 7.6-MeV groups are tentatively assigned negative and positive parities, respectively. Additional study would be useful to determine if these states are same or different.
In ²⁴Na, 2014Fi01 (n,γ) proposed J^π=(0,1,2)⁻ for 4048.8 keV level based on weaker population from the capture state (J^π=1⁺,2⁺) and mentioned to reexamine the J^π=0⁺ assignment, suggested in earlier evaluations (1990En08, 2007Fi02).
This evaluation includes the first observation of E0 transition, strength ρ²(E0)=0.380 70, for the 6432 keV transition from 0⁺ state at 6432 to 0⁺ g.s. in ²⁴Mg reported in 2020Do10. Authors proposed the first-excited 0⁺ state of ²⁴Mg to be superdeformed.
In ²⁴Al, the excited level energies deduced from (³He,t) measurements reported by different research groups vary significantly and it was not clear if some of those levels were same or different. Additional measurements are needed.
Current status of r-process nucleosynthesis
2019, Progress in Particle and Nuclear Physics
The rapid neutron capture process ( $r$ process) is believed to be responsible for about half of the production of the elements heavier than iron and contributes to abundances of some lighter nuclides as well. A universal pattern of $r$ -process element abundances is observed in some metal-poor stars of the Galactic halo. This suggests that a well-regulated combination of astrophysical conditions and nuclear physics conspires to produce such a universal abundance pattern. The search for the astrophysical site for $r$ -process nucleosynthesis has stimulated interdisciplinary research for more than six decades. There is currently much enthusiasm surrounding evidence for $r$ -process nucleosynthesis in binary neutron star mergers in the multi-wavelength follow-up observations of kilonova/gravitational-wave GRB170807A/GW170817. Nevertheless, there remain questions as to the contribution over the history of the Galaxy to the current solar-system $r$ -process abundances from other sites such as neutrino-driven winds or magnetohydrodynamical ejection of material from core-collapse supernovae. In this review we highlight some current issues surrounding the nuclear physics input, astronomical observations, galactic chemical evolution, and theoretical simulations of $r$ -process astrophysical environments with the goal of outlining a path toward resolving the remaining mysteries of the $r$ process.
Time-of-flight mass spectrometry of very exotic systems
2013, International Journal of Mass Spectrometry
Citation Excerpt :
The SPEG TOF set-up, pictured in Fig. 2, has achieved a 350 ps time resolution and 200 keV mass uncertainty. For more details see Refs. [19,22]. TOFI, pictured in Fig. 3, employs spallation via a 1 mA proton beam impinging with 800 MeV on a 1 mg/cm2 thorium target to produce neutron-rich nuclei.
Mass measurements of exotic nuclei provide critical information about their nuclear structure. Furthermore mass values are important input parameters to model various stellar processes. Though tremendous efforts in the production and mass spectrometry of nuclides far away from β-stability have been made over the past decades, most of the nuclei involved e.g. in the rapid neutron-capture process or in neutron star crust processes are not yet investigated. Moreover the general nuclear structure towards the edges of the nuclear chart remains unknown. Mass models cannot solve the ambiguity due to their diverging predictions. The time-of-flight-magnetic-rigidity (TOF-Bρ) technique discussed in this article offers the opportunity to measure the masses of nuclei in exotic regions of the nuclear chart. The precision of this experimental technique is sufficient to investigate nuclear structure, address questions of stellar nucleosynthesis, and test the predictive power of mass models.
Nuclear Data Sheets for A = 24
2007, Nuclear Data Sheets
This evaluation of A = 24 has been updated from previous evaluations published in 1998En04, 1990En08, and 1978En02. Coverage includes properties of adopted levels and γ rays, decay-scheme data (energies, intensities and placement of radiations), and cross reference entries. The following tables continue the tradition of showing the systematic relationships between levels in A = 24. These assignments are based on energy differences for states with the same J^π values, γ-ray strengths, spectroscopic factors in analog single particle (T = 1) or two particle (T = 2) transfer reactions. Isospin is not a perfect quantum number and the adopted T-value may correspond to a small component in the wavefunction.
Reaction cross-section and reduced strong absorption radius measurements of neutron-rich nuclei in the vicinity of closed shells N = 20 and N = 28
2006, Nuclear Physics A
The energy-integrated reaction cross-sections of several neutron-rich nuclei (¹⁷⁻²²N, ¹⁹⁻²⁴O, ²¹⁻²⁷F, ²³⁻³⁰Ne, ²⁶⁻³³Na, ²⁸⁻³⁵Mg, ³¹⁻³⁸Al, ³³⁻⁴⁰Si, ³⁶⁻⁴²P, ³⁹⁻⁴⁴S, ⁴²⁻⁴⁵Cl, ^45,46Ar), measured at intermediate energy (30–65 A MeV), via direct method, are presented. Silicon detectors have been used as the active target as well as for particles identification. The reduced strong absorption radii $r_{0}^{2}$ are extracted and compared to the data available from the literature. New measurements for 19 nuclei (²⁷F, ^27,30Ne, ³³Na, ^28,34–35Mg, ³⁶⁻³⁸Al, ³⁸⁻⁴⁰Si, ⁴¹⁻⁴²P, ⁴²⁻⁴⁴S, ⁴⁵Cl) are revealed. From the study of the isospin dependence of the reduced strong absorption radius, a new quadratic parameterisation of the nuclear radii in the closed shell regions $N = 8$ and $N = 28$ , is proposed. According to this parameterisation, the proton/neutron rich nuclei skin effect is well described and a new anomalous structure: halo-structure or large deformation is suggested for ³⁵Mg and ⁴⁴S nuclei.
Experimental approaches to nuclear reactions involved in explosive stellar binaries
2006, Nuclear Physics A
Explosive stellar environments such as novae and X-ray bursts are currently among the most exciting topics in nuclear astrophysics. Reactions on unstable nuclei play a crucial role in energy generation and nucleosynthesis due to the high temperatures and short reaction time scales in these events, but substantial uncertainties exist in nuclear reaction rates on unstable nuclei resulting from limited experimental data. In recent years some remarkable developments in radioactive ion beam production and experimental techniques have allowed many key reaction rates to be experimentally determined with reasonable accuracy for the first time. In this paper we review experimental methods that have recently been exploited to study reactions important in explosive binaries, highlight some key examples of recent results, and outline remaining experimental challenges.

View all citing articles on Scopus

View full text

Mass measurement of light neutron-rich fragmentation products

Abstract

Phys. Lett. B

Z. Phys.

Nucl. Phys.

Phys. Rev. Lett.