Determination of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>141</mml:mn></mml:msup></mml:math>Pr(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:mspace width="-0.16em" /><mml:mi>n</mml:mi></mml:mrow></mml:math>)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow /><mml:mn>144</mml:mn></mml:msup></mml:math>Pm cross sections at ener

Sauerwein, A.; Becker, Hans‐Werner; Dombrowski, H.; Elvers, M.; Endres, J.; Giesen, U.; Hasper, J.; Hennig, Andreas; Netterdon, L.; Rauscher, T.; Rogalla, Detlef; Zell, K. O.; Zilges, A.

doi:10.1103/physrevc.84.045808

Cited by 72 publications

(117 citation statements)

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“…This method makes it possible to investigate besides the total cross section the partial cross section for the direct population of several states in 75 As. This is an advantage compared to the widely used activation technique [28][29][30][31][32][33], which was not applicable anyway since the reaction product 75 As is stable.…”

Section: The Reactionmentioning

confidence: 99%

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
Self Cite
36
4
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0
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Background: Astrophysical models studying the origin of the neutron-deficient p nuclides require the knowledge of proton capture cross sections at low energy. The production site of the p nuclei is still under discussion but a firm basis of nuclear reaction rates is required to address the astrophysical uncertainties. Data at astrophysically relevant interaction energies are scarce. Problems with the prediction of charged particle capture cross sections at low energy were found in the comparisons between previous data and calculations in the Hauser-Feshbach statistical model of compound reactions.Purpose: A measurement of 74 Ge(p,γ) 75 As at low proton energies, inside the astrophysically relevant energy region, is important in several respects. The reaction is directly important as it is a bottleneck in the reaction flow which produces the lightest p nucleus 74 Se. It is also an important addition to the data set required to test reaction-rate predictions and to allow an improvement in the global p+nucleus optical potential required in such calculations.Method: An in-beam experiment was performed, making it possible to measure in the range 2.1 ≤ Ep ≤ 3.7 MeV, which is for the most part inside the astrophysically relevant energy window. Angular distributions of the γ-ray transitions were measured with high-purity germanium detectors at eight angles relative to the beam axis. In addition to the total cross sections, partial cross sections for the direct population of twelve levels were determined. Results:The resulting cross sections were compared to Hauser-Feshbach calculations using the code SMARAGD. Only a constant renormalization factor of the calculated proton widths allowed a good reproduction of both total and partial cross sections. The accuracy of the calculation made it possible to check the spin assignment of some states in 75 As. In the case of the 1075 keV state, a double state with spins and parities of 3/2 − and 5/2 − is needed to explain the experimental partial cross sections. A change in parity from 5/2 + to 5/2 − is required for the state at 401 keV. Furthermore, in the case of 74 Ge, studying the combination of total and partial cross sections made it possible to test the γ width, which is essential in the calculation of the astrophysical 74 As(n,γ) 75 As rate. Conclusions:Between data and statistical model prediction a factor of about two was found. Nevertheless, the improved astrophysical reaction rate of 74 Ge(p,γ) (and its reverse reaction) is only 28% larger than the previous standard rate. The prediction of the 74 As(n,γ) 75 As rate (and its reverse) was confirmed, the newly calculated rate differs only by a few percent from the previous prediction. The in-beam method with high efficiency detectors proved to be a powerful tool for studies in nuclear astrophysics and nuclear structure.

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Section: The Reactionmentioning

confidence: 99%

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
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36
4
40
0
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“…It has been found that especially at low energies huge discrepancies are found between predictions for α-induced reaction cross sections using different global α-nucleus optical potentials. This holds in particular for (α,γ) capture reactions for targets with masses above A ≈ 100 [1][2][3][4][5][6][7][8], but also the energy dependence of recent (α,n) data for 141 Pr was difficult to fit [9,10]. The total reaction cross section σ reac is related to the complex scattering matrix S L = η L exp (2iδ L ) by the well-known relation…”

Section: Introductionmentioning

confidence: 99%

Total reaction cross sectionσreacofα-induced reactions from elastic scattering: The example140Ce(
Mohr
¹

2013
Phys. Rev. C

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“…Some of the important experimental signatures of the PE emission are; (i) the presence of a larger number of high-energy particles as compared to the spectrum predicted by the CN theory, (ii) forward-peaked angular distribution of the emitted particles, (iii) slowly decreasing tails of the excitation functions (EFs) etc. The EFs data of low energy neutron capture are very useful in accurate determination of the astrophysical reaction rates for p and γ-processes [6,7]. With the motivation to study the reaction mechanism in a consistent and systematic way, the measurements and analysis of EFs for (α,n) reactions on various targets having odd Z and odd A nuclei have been undertaken.…”

Section: Introductionmentioning

confidence: 99%

Competition between the compound and the pre-compound emission processes in α-induced reactions at near astrophysical energy to well above it

Sharma¹,

Sharma

Yadav

et al. 2016

J. Phys.: Conf. Ser.

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Abstract. The study of pre-compound emission in α-induced reactions, particularly at the low incident energies, is of considerable interest as the pre-compound emission is more likely to occur at higher energies. With a view to study the competition between the compound and the pre-compound emission processes in α-induced reactions at different energies and with different targets, a systematics for neutron emission channels in targets 51 V, 55 Mn, 93 Nb, 121,123 Sb and 141 Pr at energy ranging from astrophysical interest to well above it, has been developed.The off-line γ-ray-spectrometry based activation technique has been adopted to measure the excitation functions. The experimental excitation functions have been analysed within the framework of the compound nucleus mechanism based on the Weisskopf-Ewing model and the pre-compound emission calculations based on the geometry dependent hybrid model. The analysis of the data shows that experimental excitation functions could be reproduced only when the pre-compound emission, simulated theoretically, is taken into account.The strength of pre-compound emission process for each system has been obtained by deducing the pre-compound fraction. Analysis of data indicates that in α-induced reactions, the pre-compound emission process plays an important role, particularly at the low incident energies, where the pure compound nucleus process is likely to dominate.

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Determination of141Pr(α,n)144Pm cross sections at ener

Cited by 72 publications

References 59 publications

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
Self Cite
36
4
40
0
View full text Add to dashboard Cite

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
Self Cite
36
4
40
0
View full text Add to dashboard Cite

Total reaction cross sectionσreacofα-induced reactions from elastic scattering: The example140Ce(
Mohr
¹

2013
Phys. Rev. C

Competition between the compound and the pre-compound emission processes in α-induced reactions at near astrophysical energy to well above it

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Determination of141Pr(α,n)144Pm cross sections at ener

Cited by 72 publications

References 59 publications

Investigation of the reaction74Ge(p,γ)75Sauerwein1, Endres2, Netterdon3 et al. 2012Phys. Rev. CSelf Cite364400View full textAdd to dashboardCite

Investigation of the reaction74Ge(p,γ)75Sauerwein1, Endres2, Netterdon3 et al. 2012Phys. Rev. CSelf Cite364400View full textAdd to dashboardCite

Total reaction cross sectionσreacofα-induced reactions from elastic scattering: The example140Ce(Mohr1 2013Phys. Rev. C

Competition between the compound and the pre-compound emission processes in α-induced reactions at near astrophysical energy to well above it

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About

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
Self Cite
36
4
40
0
View full text Add to dashboard Cite

Investigation of the reaction74Ge(p,γ)75
Sauerwein
¹
,
Endres
²
,
Netterdon
³

et al. 2012
Phys. Rev. C
Self Cite
36
4
40
0
View full text Add to dashboard Cite

Total reaction cross sectionσreacofα-induced reactions from elastic scattering: The example140Ce(
Mohr
¹

2013
Phys. Rev. C