First Results from the CARIBU Facility: Mass Measurements on the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>r</mml:mi></mml:math>-Process Path

Schelt, J. Van; Lascar, D.; Savard, G.; Clark, J. A.; Bertone, P. F.; Caldwell, S.; Chaudhuri, A.; Levand, A. F.; Li, G.; Morgan, G.; Orford, R.; Segel, R. E.; Sharma, K. S.; Sternberg, M.

doi:10.1103/physrevlett.111.061102

Cited by 75 publications

(61 citation statements)

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“…A large effort has been devoted to the measurement of masses, β -decay half-lives, and β -delayed neutron emission probabilities (e.g. recently [3][4][5]), however, the majority of the r-process nuclei are still not accessible. In addition, although in many environments the neutron-capture reaction rates do not play significant role in the r-process flow due to (n, γ)-(γ, n) equilib- * spyrou@nscl.msu.edu † liddick@nscl.msu.edu ‡ a.c.larsen@fys.uio.no rium, recent studies have shown significant sensitivity to the neutron-capture reaction rates in certain conditions [6].…”

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confidence: 99%

Novel technique for Constrainingr-Process (n,γ) Reaction Rates

et al. 2014

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A novel technique has been developed, which will open exciting new opportunities for studying the very neutron-rich nuclei involved in the r-process. As a proof-of-principle, the γ-spectra from the β -decay of 76 Ga have been measured with the SuN detector at the National Superconducting Cyclotron Laboratory. The nuclear level density and γ-ray strength function are extracted and used as input to Hauser-Feshbach calculations. The present technique is shown to strongly constrain the 75 Ge(n, γ) 76 Ge cross section and reaction rate.One of the most important questions in Nuclear Astrophysics is the origin of the elements heavier than iron. It is well known that there are three main processes responsible for the nucleosynthesis of the heavier elements: two neutroninduced processes (s-and r-process) that create the majority of these nuclei and a third process (p-process), which is called upon to produce the small number of neutron-deficient isotopes that are not reached by the other two processes. Although the general characteristics of these processes were proposed already more than fifty years ago [1], they are far from understood.Despite the fact that the r-process is responsible for producing roughly half of the isotopes of the heavy elements, its astrophysical site has not yet been unambiguously identified. Multiple sites have been proposed and investigated, however, to date, no firm conclusion has been drawn for where the rprocess takes place. Nevertheless, it is thought to occur in environments with a high density of free neutrons, where neutron capture reactions push the matter flow to very neutronrich nuclei, while subsequent β -decays bring the flow back to the final stable nuclei (e.g. [2]). One of the limiting factors in being able to determine the r-process site are the large uncertainties in the nuclear physics input. Because the nuclei involved in the r-process are many mass units away from the valley of stability, it is difficult, and sometimes even impossible to measure the relevant quantities directly. A large effort has been devoted to the measurement of masses, β -decay half-lives, and β -delayed neutron emission probabilities (e.g. recently [3][4][5]), however, the majority of the r-process nuclei are still not accessible. In addition, although in many environments the neutron-capture reaction rates do not play significant role in the r-process flow due to (n, γ)-(γ, n) equilib- * spyrou@nscl.msu.edu † liddick@nscl.msu.edu ‡ a.c.larsen@fys.uio.no rium, recent studies have shown significant sensitivity to the neutron-capture reaction rates in certain conditions [6]. A major recognized challenge in the field is the measurement of the relevant neutron-capture reactions since all of the participating nuclei are unstable with short half-lives. The direct determination of the (n, γ) cross sections that dominate in many cases the astrophysical r-process is not currently possible. It is therefore of paramount importance to develop indirect techniques to extract these critical reaction rates.Many differ...

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Novel technique for Constrainingr-Process (n,γ) Reaction Rates

et al. 2014

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“…Daniel Lascar played a significant role in getting the CPT moved to CARIBU and then used the facility to measure the masses of some 24 nuclei in the r-process path. These measurements, along with other mass measurements done at CARIBU, have shown that previous determinations from beta-decay data and from models are inaccurate by as much as hundreds of keV [9]. Dr. Lascar completed his PhD in 2012 and is now working in industry.…”

Section: Nuclear Mass Measurementsmentioning

confidence: 95%

Physics with Rare Isotope Beams

Segel¹

2013

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“…The highlights after AME2012 are mass measurements of very neutron rich nuclides by the ISOLTRAP group [9,16] and the first results from the CARIBU facility [17]. At the RI Beam Factory at RIKEN, many new nuclides very rich in neutron were discovered.…”

Section: Mass Measurements After Ame2012mentioning

confidence: 99%

The 2012 Atomic Mass Evaluation and Future

Wang¹,

Audi²,

Kondev³

et al. 2015

Proceedings of the Conference on Advances in Radioactive Isotope Science (ARIS2014)

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The Atomic Mass Evaluation (AME) contains the most reliable and comprehensive information for the values of the atomic masses and their uncertainties. A wealth of new, high-precision experimental data were included in the new version, AME2012, published in December 2012, and masses of many nuclides were improved significantly. The AME2012 is described and compared with the previous AME2003 evaluation. Perspectives about the future are given.

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First Results from the CARIBU Facility: Mass Measurements on ther-Process Path

Cited by 75 publications

References 46 publications

Novel technique for Constrainingr-Process (n,γ) Reaction Rates

Novel technique for Constrainingr-Process (n,γ) Reaction Rates

Physics with Rare Isotope Beams

The 2012 Atomic Mass Evaluation and Future

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