Publisher’s Note: Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>Ne</mml:mi><mml:mprescripts /><mml:none /><mml:mn>18</mml:mn></mml:mmultiscripts><mml:mo stretchy="false">(</mml:mo><mml:mi>α</mml:mi><mml:mo>,</mml:mo><mml:msub><mml:mi>p</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:mo stretchy="false">)</mml:mo><mml:mmultiscripts><mml:mi>Na</mml:mi><mml:mprescripts /><mml:none /><mml:mn>21</mml:mn></mml:mmultiscripts></mml:math>Reaction Cr

Salter, P.; Aliotta, M.; Davinson, T.; Falou, H. Al; Chen, A.; Davids, B.; Fulton, Benjamin J.; Galinski, N.; Howell, Debra; Lotay, G.; Machule, P.; Murphy, A. St. J.; Ruiz, C.; Sjue, Sky; Taggart, M.P.; Walden, P.; Woods, P. J.

doi:10.1103/physrevlett.109.069902

Cited by 13 publications

(41 citation statements)

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“…cross section. Both available data sets (6 data points in [7] and 2 data points and 3 upper limits in [8]) are in reasonable agreement with each other. As expected, the experimental ground state contribution is lower than the present total S-factor.…”

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confidence: 74%

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Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
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The18 Ne(α,p) 21 Na reaction impacts the break-out from the hot CNO-cycles to the rp-process in type I X-ray bursts. We present a revised thermonuclear reaction rate, which is based on the latest experimental data. The new rate is derived from Monte-Carlo calculations, taking into account the uncertainties of all nuclear physics input quantities. In addition, we present the reaction rate uncertainty and probability density versus temperature. Our results are also consistent with estimates obtained using different indirect approaches.PACS numbers: 25.60.-t,25.55.-e,26.30.-k I. INTRODUCTIONThere has been much interest recently in the thermonuclear rate of the 18 Ne(α,p) 21 Na reaction at temperatures of type I X-ray bursts [1,2]. Because of the high temperatures of several Giga-Kelvin (in usual notation: T 9 ≈ 1 − 2), the reaction rate is essentially defined by the cross section at energies between 1 and 3 MeV. This corresponds to excitation energies of E * ≈ 9 − 11 MeV in the compound nucleus 22 Mg. The latest studies have focused on indirect determinations of the 18 Ne(α,p) 21 Na reaction rate. Matic et al.[3] obtained excitation energies, E * , of many levels in the 22 Mg compound nucleus by measuring the 24 Mg(p,t) 22 Mg reaction. These energies define the resonance energies, E, in the 18 Ne(α,p) 21 Na reaction, which enter exponentially into the expression for the reaction rate and are thus the most important ingredient. From the same experiment, total widths Γ of these states were derived [4]. In addition, spins and parities, J π , of several states in 22 Mg have been measured recently by resonant proton scattering using the 21 Na(p,p) 21 Na reaction in inverse kinematics [5,6]. Furthermore, the reverse 21 Na (p,α) 18 Ne reaction has been used in two independent experiments [7,8] to determine a lower limit of the forward 18 Ne(α,p) 21 Na reaction cross section. Mohr and Matic [4] found a dramatic disagreement between the earlier forward 18 Ne(α,p) 21 Na reaction data obtained by Groombridge et al. [9] and the reverse reaction data [7,8]. Consequently, the data of Ref. [9] were excluded from the determination of the reaction rate in Ref. [4].Two different approaches have been used in Ref.[4] to determine the 18 Ne(α,p) 21 Na reaction rate from the available data. In the first approach, the experimental resonance energies from the 24 Mg(p,t) 22 Mg reaction [3], together with α-transfer data for the mirror compound nucleus 22 Ne [3], were employed for calculating * Email: WidmaierMohr@t-online.de the required resonance strengths, ωγ αp . In the second approach, the experimental reverse reaction data [7,8] were corrected for thermal target excitations by using a Hauser-Feshbach model and the forward rate was obtained using the reciprocity theorem. It was shown in Ref.[4] that the reaction rates obtained by these two methods differ by a factor of ≈3. Taking into account estimated uncertainties of a factor of ≈2 for both approaches, the geometric mean value has been recommended in Ref. [4]. The present st...

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confidence: 74%

“…As expected, the experimental ground state contribution is lower than the present total S-factor. 18 Ne reaction [7,8] …”

Section: Determination Of Resonance Strengthsmentioning

confidence: 99%

Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
View full text Add to dashboard Cite

show abstract

“…In a comparison of the new recommended rate factor N A < σv > recommended with the SAL result (see Table II in [5]) it has to be kept in mind that SAL provide the rate factor for the ground-state contribution 18 Ne(α,p 0 ) 21 Na g.s. which is derived from their experimental data; the given upper and lower limits are calculated from their experimental uncertainties, but do not include the additional contributions of the (α,p i =0 ) channels and the corresponding uncertainties.…”

Section: Recommended Reaction Ratementioning

confidence: 99%

“…However, experiments remain very difficult because of the short-living 18 Ne nucleus (T 1/2 = 1.67 s) and the limited intensity of radioactive beam facilities. Thus, besides the direct approach of measuring the 18 Ne(α,p) 21 Na reaction cross section [3,4], the reverse 21 Na(p,α) 18 Ne reaction has been studied very recently [5] and in an earlier unpublished experiment [6], and the resonance energies have been determined from various transfer experiments populating states in the compound 22 Mg nucleus [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Examination and experimental constraints of the stellar reaction rate factorNA〈σv〉of the18Ne(
Matić
¹
,
Mohr
²

2013
Phys. Rev. C

168

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The18 Ne(α,p) 21 Na reaction is one key for the break-out from the hot CNO-cycles to the rpprocess. Recent papers have provided reaction rate factors NA < σv > which are discrepant by at least one order of magnitude. The compatibility of the latest experimental results is tested, and a partial explanation for the discrepant NA < σv > is given. A new rate factor is derived from the combined analysis of all available data. The new rate factor is located slightly below the higher rate factor by Matic et al. at low temperatures and significantly below at higher temperatures whereas it is about a factor of five higher than the lower rate factor recently published by Salter et al.

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“…However, a recent effort at the ISAC-II facility of TRIUMF led by the University of Edinburgh group to measure the cross section of the timereversed reaction p( 21 Na,α) 18 Ne has allowed a reliable determination of the 18 Ne(α, p 0 ) 21 Na reaction cross section from 1.2-2.6 MeV. 50 The experimental cross section was found to be up to a factor of two smaller than theoretical predictions based on Hauser-Feshbach calculations, suggesting that the breakout via this reaction occurs at higher temperatures and later times than previously believed. Direct measurements with an intense 18 Ne beam will be required in order to make further progress.…”

Section: Cataclysmic Binary Systems Compact Objects and Supernovaementioning

confidence: 99%

Outstanding problems in nuclear astrophysics: recent progress at TRIUMF

Davids

2014

AIP Advances

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Publisher’s Note: Measurement of theNe18(α,p0)Na21Reaction Cr

Cited by 13 publications

References 0 publications

Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
View full text Add to dashboard Cite

Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
View full text Add to dashboard Cite

Examination and experimental constraints of the stellar reaction rate factorNA〈σv〉of the18Ne(
Matić
¹
,
Mohr
²

2013
Phys. Rev. C

Outstanding problems in nuclear astrophysics: recent progress at TRIUMF

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Publisher’s Note: Measurement of theNe18(α,p0)Na21Reaction Cr

Cited by 13 publications

References 0 publications

Thermonuclear reaction rate ofNe18(α,p)Na21Mohr1, Longland2, Iliadis3 2014Phys. Rev. C2618932View full textAdd to dashboardCite

Thermonuclear reaction rate ofNe18(α,p)Na21Mohr1, Longland2, Iliadis3 2014Phys. Rev. C2618932View full textAdd to dashboardCite

Examination and experimental constraints of the stellar reaction rate factorNA〈σv〉of the18Ne(Matić1, Mohr2 2013Phys. Rev. C

Outstanding problems in nuclear astrophysics: recent progress at TRIUMF

Contact Info

Product

Resources

About

Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
View full text Add to dashboard Cite

Thermonuclear reaction rate ofNe18(α,p)Na21
Mohr¹,
Longland²,
Iliadis³
2014
Phys. Rev. C
26
18
93
2
View full text Add to dashboard Cite

Examination and experimental constraints of the stellar reaction rate factorNA〈σv〉of the18Ne(
Matić
¹
,
Mohr
²

2013
Phys. Rev. C