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 isomer production via fast fragmentation

Chipps, K. A.; Kozub, R. L.; Sumithrarachchi, C.; Ginter, T. N.; Baumann, T.; Lund, K.; Lapierre, A.; Villari, A. C. C.; Montes, F.; Jin, S. L.; Schmidt, K.; Ayoub, Sara; Pain, S. D.; Blankstein, D.

doi:10.1103/physrevaccelbeams.21.121301

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…Other well-known nuclei with astromers include 34 Cl (possibly visible in nova bursts, isomer at 146 keV [24,34]) and 85 Kr (in the slow neutron capture (s) process a branch point, in the r process a β-decay accelerant and possible electromagnetic source; isomer at 305 keV [35,36]). Isomers, including the 130 keV isomer in 38 K, may play a role in the rapid proton capture process (rp process) [37][38][39][40]. 176 Lu can be an s-process thermometer [41], and geochemists use it as a chronometer [42][43][44][45], both of which are influenced by its isomer at 123 keV.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

et al. 2021

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Nuclear isomers are populated in the rapid neutron capture process (r process) of nucleosynthesis. The r process may cover a wide range `of temperatures, potentially starting from several tens of GK (several MeV) and then cooling as material is ejected from the event. As the r-process environment cools, isomers can freeze out of thermal equilibrium or be directly populated as astrophysically metastable isomers (astromers). Astromers can undergo reactions and decays at rates very different from the ground state, so they may need to be treated independently in nucleosythesis simulations. Two key behaviors of astromers—ground state ↔ isomer transition rates and thermalization temperatures—are determined by direct transition rates between pairs of nuclear states. We perform a sensitivity study to constrain the effects of unknown transitions on astromer behavior. Detailed balance ensures that ground → isomer and isomer → ground transitions are symmetric, so unknown transitions are equally impactful in both directions. We also introduce a categorization of astromers that describes their potential effects in hot environments. We provide a table of neutron-rich isomers that includes the astromer type, thermalization temperature, and key unmeasured transition rates.

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Section: Introductionmentioning

confidence: 99%

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

et al. 2021

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“…129 Sn: Second r-process peak (A ∼ 130) nuclide. 34 126 Sb: Second r-process peak (A ∼ 130) nuclide. 6 measured levels, 6 in this calculation.…”

Section: Resultsmentioning

confidence: 99%

“…The ground state of 26 Al has a β-decay half-life of ∼700 kyr, while its isomer decays with a half-life of ∼6 s. This nuclide-the first radioisotope to be observed in the heavens-is an important tracer of star formation [26][27][28]. Other well-known nuclei with astromers include 34 Cl (possibly visible in nova bursts, isomer at 146 keV [20,29]) and 85 Kr (in the slow neutron capture (s) process a branch point, in the r process a β-decay accelerant and possible electromagnetic source; isomer at 305 keV [30,31]). Isomers, including the 130 keV isomer in 38 K, may play a role in the rapid proton capture process (rp process) [32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

“…Other well-known nuclei with astromers include 34 Cl (possibly visible in nova bursts, isomer at 146 keV [20,29]) and 85 Kr (in the slow neutron capture (s) process a branch point, in the r process a β-decay accelerant and possible electromagnetic source; isomer at 305 keV [30,31]). Isomers, including the 130 keV isomer in 38 K, may play a role in the rapid proton capture process (rp process) [32][33][34][35]. 176 Lu can be an s-process thermometer [36], and geochemists use it as a chronometer [37][38][39][40], both of which are influenced by its isomer at 123 keV.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

Misch¹,

Sprouse²,

Mumpower³

et al. 2021

Preprint

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Nuclear isomers are populated in the rapid neutron capture process (r process) of nucleosynthesis. The r process may cover a wide range of temperatures, potentially starting from several tens of GK (several MeV) and then cooling as material is ejected from the event. As the r-process environment cools, isomers can freeze out of thermal equilibrium or be directly populated as astrophysical isomers (astromers). Two key behaviors of astromers-ground state ↔ isomer transition rates and thermalization temperatures-are determined by direct transition rates between pairs of nuclear states. We perform a sensitivity study to constrain the effects of unknown transitions on astromer behavior. We also introduce a categorization of astromers that describes their potential effects in hot environments. We provide a table of neutron-rich isomers that includes the astromer type, thermalization temperature, and key unmeasured transition rates.

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“…A few applications of this approach are detailed in Refs. [1,2,3,4,5,6,7,8,9,10,11]. One reaction method that has shown promise for producing 16 N reaction from the DWBA approach at reaction energies of (a) 7.9 MeV/u and (b) 13.2 MeV/u.…”

Section: Introductionmentioning

confidence: 99%

In-flight production of an isomeric beam of $^{16}$N

Hoffman,

Tang,

Avila

et al. 2022

Preprint

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An in-flight beam of 16 N was produced via the single-neutron adding (d,p) reaction in inverse kinematics at the recently upgraded Argonne Tandem Linear Accelerator System (ATLAS) in-flight system. The amount of the 16 N beam which resided in its excited 0.120-MeV J π = 0 − isomeric state (T 1/2 ≈ 5 µs) was determined to be 40(5)% at a reaction energy of 7.9(3) MeV/u, and 24(2)% at a reaction energy of 13.2(2) MeV/u. The isomer measurements took place at an experimental station ≈ 30 m downstream of the production target and utilized an Al beam-stopping foil and a HPGe Clover detector. Composite 16 N beam rate determinations were made at the experimental station and the focal plane of the Argonne in-flight radioactive ion-beam separator (RAISOR) with Si ∆E-E telescopes. A Distorted Wave Born Approximation (DWBA) approach was coupled with the known spectroscopic information on 16 N in order to estimate the relative 16 N isomer yields and composite 16 N beam rates. In addition to the observed reaction-energy dependence of the isomer fraction, a large sensitivity to angular acceptance of the recoils was also observed.

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K38 isomer production via fast fragmentation

Cited by 8 publications

References 21 publications

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

In-flight production of an isomeric beam of $^{16}$N

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