A survey of new resonances in the <sup>15</sup>N(α,γ)<sup>19</sup>F reaction

Aitken, J.H.; Azuma, R.E.; Litherland, A.E.; Charlesworth, A.M.; Rogers, D. W. O.; Simpson, John

doi:10.1139/p70-203

Cited by 22 publications

(10 citation statements)

References 1 publication

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“…Thus we will disregard in the following discussion other resonances and the direct capture process. 2 During the near completion of the present work, we became aware of the recent measurement by Lotay et al [156]. They locate this particular resonance at E cm r = 68.3 ± 0.7 keV and find evidence that it is formed via d-waves rather than s-waves as assumed here.…”

Section: Rate Ofsupporting

confidence: 56%

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

et al. 2010

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Numerical values of charged-particle thermonuclear reaction rates for nuclei in the A=14 to 40 region are tabulated. The results are obtained using a method, based on Monte Carlo techniques, that has been described in the preceding paper of this series (Paper I). We present a low rate, median rate and high rate which correspond to the 0.16, 0.50 and 0.84 quantiles, respectively, of the cumulative reaction rate distribution. The meaning of these quantities is in general different from the commonly reported, but statistically meaningless expressions, "lower limit", "nominal value" and "upper limit" of the total reaction rate. In addition, we approximate the Monte Carlo probability density function of the total reaction rate by a lognormal distribution and tabulate the lognormal parameters µ and σ at each temperature. We also provide a quantitative measure (Anderson-Darling test statistic) for the reliability of the lognormal approximation. The user can implement the approximate lognormal reaction rate probability density functions directly in a stellar model code for studies of stellar energy generation and nucleosynthesis. For each reaction, the Monte Carlo reaction rate probability density functions, together with their lognormal approximations, are displayed graphically for selected temperatures in order to provide a visual impression. Our new reaction rates are appropriate for bare nuclei in the laboratory. The nuclear physics input used to derive our reaction rates is presented in the subsequent paper of this series (Paper III). In the fourth paper of this series (Paper IV) we compare our new reaction rates to previous results.

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Section: Rate Ofsupporting

confidence: 56%

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

et al. 2010

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“…A yield curve over the complete region of interest taken with a thick target is given in Aitken et al (1970). In order to separate the resonances at 2.61 and 2.63 MeV a thin (-7 keV thick to 2.7 MeV alphas) target was used to obtain the yield curve in Fig.…”

Section: Yield Curvementioning

confidence: 99%

“…3 have been obtained from these spectra and the angular distribution spectra. The limits on the weak feeds from the 2.04 MeV resonance have been taken from the data of Aitken et al (1970).…”

Section: Gamma Decays and Energy Calibrationsmentioning

confidence: 99%

Resonances in the ¹⁵N(α,γ)¹⁹F Reaction Between E_α = 1.68 and 2.72 MeV

Rogers¹,

Beukens²,

Diamond³

1972

Can. J. Phys.

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Using the '5N(u,y)'9F reaction, the properties of 6 levels between 5.3 and 6.2 MeV in ' 9~ have been studied. In conjunction wlth previously reported restrictions on spins for these levels, measurements of branching ratios, radiative widths, and angular distributions have been used to make the following spin-parity assignments; 5618 keV, 312-; 5938 keV, 112' ; 6070 keV, 712' ; 6088 keV, 312-; 6160 keV, 712-. The properties of these levels and that at 5336 keV have been compared in detail to the various shell model calculations done for I9F. The properties of the third J" = 712' level at 6.07 MeV can be used to clear up some of the confusion caused by the first two J" = 7/2+ levels in 19F and the properties of the J" = 312-levels confirm the fact that the weak coupling model does not explain the negative parity states outside the K = 112-band.On a etudie les proprittts de 6 niveaux du 19F entre 5.3 et 6.2 MeV en utilisant la reaction '5N(a,.1)'9F. En rapport avec les restrictions rapportees anttrieurement sur les spins de ces niveaux, les mesures des rapports de branchement, des largeurs de rayonnement et des distributions angulaires ont t t t utilisees pour en arriver aux attributions suivantes de spin et de parite: 5618 keV, 312-; 5938 keV, 112' ; 6070 keV, 712' ; 6088 keV, 312-; 6160 keV, 712-. Les proprietts de ces niveaux et celles du niveau s i t d B 5336 keV ont t t t comparees en detail aux differents calculs bases sur le modele en couche pour le 19F. Les proprittts du troisieme niveau J n = 7/2+, a 6.07 MeV, peuvent &tre utilisees pour eliminer une certaine confusion causie par les deux premiers niveaux J" = 712' du 19F; les proprittts des niveaux J" = 312-confirment le fait que le modele a couplage faible n'explique pas les ttats de parite negative en dehors de la bande K = 112-.

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“…Their value of the radiative width o y is 1.64 + 0.16 (which supersedes the value in Aitken et al 1970). The ratio of radiative widths of two resonances in the same reaction is given by where the stopping powers E were taken from the tables of Williamson et al (1966) and Y , the thick target yield per incident particle for each of these resonances, was determined using a 5 x 4 in.…”

Section: ( H ) Radiatice Width Measurementmentioning

confidence: 93%

“…The spins, parities and lifetimes of the first three states are well established (as summarized by Poletti et al 1969). Aitken et al (1968) have shown that the states at 4033 and 4000 keV are most likely 912-and 712-while the state at 5.42 MeV is definitely 712-. Middleton (1970) has observed strong triton groups in the 15N('Li,t)19F reaction corresponding to the first 5 negative parity states in 19F and also for states at 8.…”

Section: Introductionmentioning

confidence: 94%

The 5/2⁻ Resonance at 850 keV in ¹⁵N(α,γ)¹⁹F

Rogers¹,

Aitken²,

Litherland³

1972

Can. J. Phys.

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A weak resonance at 850 keV in 15N(a,y)19F corresponding to a level at 4681 f 1 keV in I9F has been found. Angular distributions and Doppler shifts have been measured for the primary decays to the 512-level at 1.35 MeV (63%), 312-level at 1.46 MeV (31%). and the 5/2+ level at 197 keV (6%). A spin of 512 has been assigned to the resonance level and negative parity is shown to be very likely. The lifetime of the resonance was measured by the Doppler shift attenuation method to be T = (15.4 f 3.0) x 10-l5 s or r = 42.8 + 8.5 meV. The measured value of my was 6.0 + 1.0 meV. These measurements together with previous -information on r , / r imply the observed MI transition strengths are a factor of 20 weaker than predicted for the 512 member of the K = 312-band in I9F which has previously been associated with this level. Une faible resonance a 850 keV dans 15N(a,y)LgF correspondant a un niveau a 4681 + I keV dans le IyF a ete trouvee. Les distributions angulaires et les effets Doppler ont Cte mesures pour les desintegrations primaires vers le niveau 512-a 1.35 MeV (63%), le niveau 312-a 1.46 MeV (31 %) et le niveau 5/2+ a 197 keV (6%).Un spin 512 a it6 attribuC au niveau de resonance et on montre qu'une parite negative est tris probable. La vie rnoyenne de la resonance a ete evaluk par la methode de I'atttnuation de I'effet Doppler a r = (15.4 f 3.0) x 10-l5 sou r = 42.8 + 8.5 MeV. La valeur rnesuree de wy est 6.0 + 1.0 meV. Ces mesures ainsi que I'inforrnation anterieurs sur T,/T irnpliquent que les forces de transition M1 observees sont plus faibles par un facteur 20 que celles predites pour le rnernbre 512 de la bande K = 312-dans le "F qui a ete anterieurement associe a ce niveau.

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A survey of new resonances in the ¹⁵N(α,γ)¹⁹F reaction

Abstract: Thirteen new resonances in the 15N(p,y)lgF reaction have been discovered in the region Em = 600-3150 keV. y-Decay schemes and radiative yields are reported for several of them. Spins and parities for 10 levels in 19F are also reported.

Cited by 22 publications

References 1 publication

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

Resonances in the ¹⁵N(α,γ)¹⁹F Reaction Between E_α = 1.68 and 2.72 MeV

The 5/2⁻ Resonance at 850 keV in ¹⁵N(α,γ)¹⁹F

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A survey of new resonances in the 15N(α,γ)19F reaction

Abstract: Thirteen new resonances in the 15N(p,y)lgF reaction have been discovered in the region Em = 600-3150 keV. y-Decay schemes and radiative yields are reported for several of them. Spins and parities for 10 levels in 19F are also reported.

Cited by 22 publications

References 1 publication

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

Resonances in the 15N(α,γ)19F Reaction Between Eα = 1.68 and 2.72 MeV

The 5/2− Resonance at 850 keV in 15N(α,γ)19F

Contact Info

Product

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A survey of new resonances in the ¹⁵N(α,γ)¹⁹F reaction

Resonances in the ¹⁵N(α,γ)¹⁹F Reaction Between E_α = 1.68 and 2.72 MeV

The 5/2⁻ Resonance at 850 keV in ¹⁵N(α,γ)¹⁹F