A precision measurement of reaction thresholds

Parks, P. B.; Beard, Percy Morris; Bilpuch, E.G.; Newson, H.W.

doi:10.1016/0029-5582(66)90317-8

Cited by 22 publications

(2 citation statements)

References 18 publications

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“…This region of the 3TAr spectrum, after subtraction of an exponential background, is shown in the inset of Figure 1. We assign this peak as being due to protons from the 37Ar(nth,p)37C1 reaction, since the corresponding Qp value 1600_+ 12keV is in excellent agreement with the value 1597_+ 1 keV found by Parks et al [17] for the inverse reaction. From the contents of the proton peak, 4180_+400 counts, and of the alpha peak, 119460+_350 counts, the ratio of the alpha to proton widths for the 3BAr capturing state was determined to be FjFp=28.5 -+ 2.7.…”

Section: Irradiation Of 348d 3:arsupporting

confidence: 69%

Thermal neutron induced charged particle reactions in radioactive targets of37Ar,109Cd,125Xe,127Xe, and132Cs

et al. 1978

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Thermal neutron induced charged particle reactions in a radioactive target of 37Ar have been studied. Upper limits of the cross-sections for the (n,~) reaction in radioactive targets of l~ 125, 12 7Xe ' and 132Cs have been obtained. The isotopically pure targets were produced at the ISOLDE facility at CERN and irradiated with thermal neutrons at the high flux reactor of the Institute Laue-Langevin in Grenoble. Charged particles from (n,p) and (n,c% reactions in 3TAr were observed with cross-sections of 69_+ 14b and 1970 _+330b, respectively. The Q-values for these reactions were determined to be 1600 _+12keV and 4630_+7keV, in agreement with existing mass data. The branching ratio F~/F, of the 3VAr capturing state was found to be 28.5+_2.7. An upper limit of the crosssection for the (n,7a) reaction in 3TAr was obtained.Nuclear reactions 3VAr(n,p); 3VAt, 1~ 125, 12VXe ' 132Cs(n,~); E, = thermal ; measured Qp, Q~, FjF~, deduced G,p, a,,.~. Isotopically pure targets. Si surface barrier detector.

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Section: Irradiation Of 348d 3:arsupporting

confidence: 69%

Thermal neutron induced charged particle reactions in radioactive targets of37Ar,109Cd,125Xe,127Xe, and132Cs

et al. 1978

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“…In the context of the last two applications, studies on proton and neutron-induced reactions on 40 Ar at MeVscale energies, are useful in the development of diagnostics tools, for testing experimental setups [10], and for background characterization [11] in long-baseline experiments. Currently, the only available experimental data for the 40 Ar(p,n) 40 K reaction at energies below 20 MeV, come from low energy neutron yield measurements for the determination of reaction thresholds, Q-values, and Isobaric Analog States [12][13][14][15]. The energy resolution of some of these earlier works is comparable to the data presented here, but the absolute quantification of the crosssection was not a primary goal of the authors.…”

Section: Introductionmentioning

confidence: 68%

Constraining the destruction rate of $^{40}$K in stellar nucleosynthesis through the study of the $^{40}$Ar(p,n)$^{40}$K reaction

Gastis,

Perdikakis,

Dissanayake

et al. 2020

Preprint

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Background: 40 K plays a significant role in the radiogenic heating of earth-like exoplanets, which can affect the development of a habitable environment on their surfaces. The initial amount of 40 K in the interior of these planets depends on the composition of the interstellar clouds from which they formed. Within this context, nuclear reactions that regulate the production of 40 K during stellar evolution can play a critical role. Purpose: In this study, we constrain for the first time the astrophysical reaction rate of 40 K(n,p) 40 Ar, which is responsible for the destruction of 40 K during stellar nucleosynthesis. We provide to the nuclear physics community high-resolution data on the cross-section and angular distribution of the 40 Ar(p,n) 40 K reaction. These are important to various applications involving 40 Ar. The associated reaction rate of the 40 Ar(p,n) 40 K process addresses a reaction rate gap in the JINA REACLIB database in the region of intermediate-mass isotopes Methods: We performed differential cross-section measurements on the 40 Ar(p,n) 40 K reaction, for six energies in the center-of-mass between 3.2 and 4.0 MeV and various angles between 0 • and 135 • . The experiment took place at the Edwards Accelerator Laboratory at Ohio University using the beam swinger target location and a standard neutron time-of-flight technique. We extracted total and partial cross-sections by integrating the double differential cross-sections we measured. Results: The total and partial cross-sections varied with energy due to the contribution from isobaric analog states and Ericson type fluctuations. The energy-averaged neutron angular distributions were symmetrical relative to 90 • . Based on the experimental data, local transmission coefficients were extracted and were used to calculate the astrophysical reaction rates of 40 Ar(p,n) 40 K and 40 K(n,p) 40 Ar reactions. The new rates were found to vary significantly from the theoretical rates in the REACLIB library. We implemented the new rates in network calculations to study nucleosynthesis via the slow neutron capture process, and we found that the produced abundance of 40 K is reduced by up to 10% compared to calculations with the library rates. At the same time, the above result removes a significant portion of the previous theoretical uncertainty on the 40 K yields from stellar evolution calculations. Conclusions: Our results support that the destruction rate of 40 K in massive stars via the 40 K(n,p) 40 Ar reaction is larger compared to previous estimates. The rate of 40 K destruction via the 40 K(n,p) 40 Ar reaction now has a dramatically reduced uncertainty based on our measurement. This result directly affects the predicted stellar yields of 40 K from nucleosynthesis, which is a critical input parameter for the galactic chemical evolution models that are currently employed for the study of significant properties of exoplanets.

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19-Potassium

Sukhoruchkin

Soroko

Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms

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A precision measurement of reaction thresholds

Cited by 22 publications

References 18 publications

Thermal neutron induced charged particle reactions in radioactive targets of37Ar,109Cd,125Xe,127Xe, and132Cs

Thermal neutron induced charged particle reactions in radioactive targets of37Ar,109Cd,125Xe,127Xe, and132Cs

Constraining the destruction rate of $^{40}$K in stellar nucleosynthesis through the study of the $^{40}$Ar(p,n)$^{40}$K reaction

19-Potassium

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