Combined Magnetic Spectrograph and Spectrometer

Enge, H.A.

doi:10.1063/1.1716028

Cited by 66 publications

(87 citation statements)

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“…[6] was determined solely based on Hauser-Feshbach calculations, which introduced 4 orders of magnitude uncertainty in the reaction rate. Consequently, variations of factors of ∼25, 136 and 58 were found in the predicted 38 Ar, 39 K and 40 Ca final abundances, respectively [6].…”

Section: Introductionmentioning

confidence: 92%

“…Whereas, nova models [18] predict such abundances to be generally close to the solar values. A sensitivity study performed by Iliadis et al [6] * ksetood@ncsu.edu identified the 38 K(p, γ) 39 Ca reaction as one of the few reactions affecting the simulated nova abundances for Ar and Ca.…”

Section: Introductionmentioning

confidence: 99%

“…The 38 K(p, γ) 39 Ca reaction rate of Ref. [6] was determined solely based on Hauser-Feshbach calculations, which introduced 4 orders of magnitude uncertainty in the reaction rate.…”

Section: Introductionmentioning

confidence: 99%

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Excited states of Ca39 and their significance in nova nucleosynthesis

et al. 2018

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Background: Discrepancies exist between the observed abundances of argon and calcium in oxygen-neon nova ejecta and those predicted by nova models. An improved characterization of the 38 K(p, γ) 39 Ca reaction rate over the nova temperature regime (∼ 0.1-0.4 GK), and thus the nuclear structure of 39 Ca above the proton threshold (5770.92(63) keV), is necessary to resolve these contradictions. Purpose: The present study was performed to search for low-spin proton resonances in the 38 K + p system, and to improve the uncertainties in energies of the known astrophysically significant proton resonances in 39 Ca. Method: The level structure of 39 Ca was investigated via high-resolution charged-particle spectroscopy with an Enge split-pole spectrograph using the 40 Ca(3 He, α) 39 Ca reaction. Differential cross sections were measured over 6 laboratory angles at 21 MeV. Distorted-wave Born approximation calculations were performed to constrain the spin-parity assignments of observed levels with special attention to those significant in determination of the 38 K(p, γ) 39 Ca reaction rate over the nova temperature regime. Results: The resonance energies corresponding to two out of three astrophysically important states at 6154(5) and 6472.2(24) keV are measured with better precision than previous charged-particle spectroscopy measurements. A tentatively new state is discovered at 5908(3) keV. The spinparity assignments of a few of the astrophysically important resonances are determined. Conclusions: The present 38 K(p, γ) 39 Ca upper limit thermonuclear reaction rate at 0.1-0.4 GK is higher than that determined in [Physical Review C 97 (2018) 025802] by at most a factor of 1.4 at 0.1 GK.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Excited states of Ca39 and their significance in nova nucleosynthesis

et al. 2018

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“…Also, a quadrupole lens improves the solid angle of the instrument when it is operated as a spectrometer. 12 The spectrograph was calibrated with alpha particles from a Po 210 source prepared in the manner described by Browne et al u The alpha-particle energy was taken to be 5.3045 MeV. The resolution width of the spectrograph is smaller than 0.1% in energy at a solid angle of 3X 10~4 sr.…”

Section: Methodsmentioning

confidence: 99%

Level Structure ofBi208as Observed at High Resolution with theBi209
Erskine
¹

1964
Phys. Rev.
57
1
3
0
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“…In this experiment, a ' C beam interacted in a thin (nominally 25 pg/cm ) isotopically enriched ' C target. Alpha particles emitted at 0' signaling the formation of excited levels in Ne were focused by a quadrupole singlet with an effective solid angle of approximately 8 msr and dispersed in momentum by a 65 cm Spectromagnetic Industries magnetic spectrometer [37] and detected by a position sensitive silicon surface barrier detector [24]. Coincidences between a particles in the forward direction and the electron detector described above were used to identify those events which involve the first excited state of ' O. Bombarding energies of 36.3 and 61 MeV were used in the ' C+' C experiment.…”

Section: Results and Analysismentioning

confidence: 99%

[16O(02+)+α] parentage of continuum levels in
Laymon
¹
,
Brown
²
,
Balamuth
³

1992
Phys. Rev. C
7
0
3
0
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A search for continuum levels in ' Ne with a large [' O(Oz+ )+a] parentage has been conducted using both resonant and direct production processes. The differential cross section for the ' 0(a, al)' 0 (02+) reaction has been measured at 13 to 26 angles for bombarding energies from E = 10.2 to 18 MeV, mostly in 25 keV steps. Events leading to the first excited state in ' 0 were identified by requiring the coincident observation of an a particle and an electron or positron from the internal pair decay of the ' 0 first excited state. Amplitudes of individual partial waves were extracted from the data by parametrizing the angular distributions in terms of the complex zeros of the scattering amplitudes. An R-matrix analysis of the data reveals a J =2+ level at E =13.1 MeV with a spectroscopic factor 8 )63%. 1 Several individual levels, a region of overlapping J =4+ levels from E, =13.69 to 14.93 MeV and a region of J =6+ levels from E"=16.73 to 18.73 MeV, have also been analyzed in detail. Branching ratios of Ne levels to the first excited state in ' 0 have been measured by populating the levels with the reaction ' C(' C, n) Ne* and observing their subsequent a decay to the 02+ state of ' 0. A J"=6+ level at E"=15. 16 MeV and a J =8+ level at E"=18. 54 MeV, which had previously been suggested as members of a rotational band based on the J =0+ level in Ne at E"=12. 44 MeV are shown to have small values of 6,arguing against this identification.

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Combined Magnetic Spectrograph and Spectrometer

Cited by 66 publications

References 1 publication

Excited states of Ca39 and their significance in nova nucleosynthesis

Excited states of Ca39 and their significance in nova nucleosynthesis

Level Structure ofBi208as Observed at High Resolution with theBi209
Erskine
¹

1964
Phys. Rev.
57
1
3
0
View full text Add to dashboard Cite

[16O(02+)+α] parentage of continuum levels in
Laymon
¹
,
Brown
²
,
Balamuth
³

1992
Phys. Rev. C
7
0
3
0
View full text Add to dashboard Cite

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Combined Magnetic Spectrograph and Spectrometer

Cited by 66 publications

References 1 publication

Excited states of Ca39 and their significance in nova nucleosynthesis

Excited states of Ca39 and their significance in nova nucleosynthesis

Level Structure ofBi208as Observed at High Resolution with theBi209Erskine1 1964Phys. Rev.57130View full textAdd to dashboardCite

[16O(02+)+α] parentage of continuum levels inLaymon1, Brown2, Balamuth3 1992Phys. Rev. C7030View full textAdd to dashboardCite

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About

Level Structure ofBi208as Observed at High Resolution with theBi209
Erskine
¹

1964
Phys. Rev.
57
1
3
0
View full text Add to dashboard Cite

[16O(02+)+α] parentage of continuum levels in
Laymon
¹
,
Brown
²
,
Balamuth
³

1992
Phys. Rev. C
7
0
3
0
View full text Add to dashboard Cite