R.B. Vogelaar

Constraining 26Al+p resonances using 26Al(3He,d)27Si.

The {sup 26}Al({sup 3}He,{ital d}){sup 27}Si reaction was measured from 0{degree}{le}{theta}{sub c.m.}{le}35{degree} at {ital E}({sup 3}He)=20 MeV using a quadrupole-dipole-dipole-dipole magnetic spectrometer. States in {sup 27}Si were observed above the background at 7652 and 7741 keV and upper limits were set for the state at 7592 keV. Implications for the {sup 26}Al({ital p},{gamma}){sup 27}Si stellar reaction rate are discussed. {copyright} {ital 1996 The American Physical Society.}

The Princeton separator, past and future

Abstract Some past research applications of the Princeton separator are reviewed. The future program envisaged includes fundamental β decay studies, low temperature nuclear orientation and nuclear astrophysics.

Investigating the astrophysically important Ex = 2.646 MeV state in 20Na

Abstract Observations of neon lines in the spectra of energetic novae have prompted a renewed look at explosive hydrogen burning. The 19Ne(p, γ)20Na reaction is expected to play a major role in the breakout of the hot CNO cycle to the rp-process, which can process CNO nuclei to heavier elements. The reaction rate is dominated by the lowest resonance in the 19Ne + p system, corresponding to the Ex = 2.646 MeV state in 20Na. A large variety of nuclear experimental techniques have been used to study this state; e.g. charge exchange reactions, β-delayed proton decay and radioactive beams. Their results have lead to a Jπ = 3+ assignment for this state [B. Brown et al., Phys. Rev. C 48 (1993) 1456], allowing an estimate of the proton width (Γp). This leaves the gamma width (Γγ) to be determined. We have performed 20Ne(3He, experiments to measure the branching ratio ( Γ γ Γ ) of the Ex = 2.646 MeV excited state in 20Na.

Measurement of the Γγ/Γtot of the Ex=2.646 MeV state in 20Na

In energetic nova events, breakout of the hot CNO cycle may proceed via the reaction chain 15O(α,γ)19Ne(p,γ)20Na. This triggers a sequence of rapid proton captures and beta decays which can process CNO nuclei to heavier elements (rp‐process). The rate of the 19Ne(p,γ)20Na reaction is sensitive to resonances in the 19Ne+p system. The first excited state above the proton threshold of 2.199 MeV in 20Na (at Ex=2.646 MeV) is expected to be the most important in determining the reaction rate. The gamma width (Γγ) of this state is still unknown and the Jπ assignment of this state is currently the subject of debate (1). We have performed 20Ne(3He,tγ) experiments to determine the branching ratio Γγ/Γ of the Ex=2.646 MeV excited state in 20Na. Some preliminary results of these experiments will be presented.

Constraining {sup 26}Al+{ital p} resonances using {sup 26}Al({sup 3}He,{ital d}){sup 27}Si

The {sup 26}Al({sup 3}He,{ital d}){sup 27}Si reaction was measured from 0{degree}{le}{theta}{sub c.m.}{le}35{degree} at {ital E}({sup 3}He)=20 MeV using a quadrupole-dipole-dipole-dipole magnetic spectrometer. States in {sup 27}Si were observed above the background at 7652 and 7741 keV and upper limits were set for the state at 7592 keV. Implications for the {sup 26}Al({ital p},{gamma}){sup 27}Si stellar reaction rate are discussed. {copyright} {ital 1996 The American Physical Society.}

Constraining Al-26 + p resonances using Al-26 (He-3, d) Si-27

The {sup 26}Al({sup 3}He,{ital d}){sup 27}Si reaction was measured from 0{degree}{le}{theta}{sub c.m.}{le}35{degree} at {ital E}({sup 3}He)=20 MeV using a quadrupole-dipole-dipole-dipole magnetic spectrometer. States in {sup 27}Si were observed above the background at 7652 and 7741 keV and upper limits were set for the state at 7592 keV. Implications for the {sup 26}Al({ital p},{gamma}){sup 27}Si stellar reaction rate are discussed. {copyright} {ital 1996 The American Physical Society.}