R. M. Chasteler

Energy levels of light nuclei A = 18-19

Compilation of energy levels of A = 18 and 19 nuclei, with emphasis on the review of material leading to information about the structure of the A = 18 and 19 systems.

Correction factors for γ-ray relative intensities in the 66Ga radioisotope

Abstract We present here strong evidence that recently published values for the relative intensities of γ-ray lines in the 66 Ga(β + + EC) 66 Zn decay are incorrect at the higher energies (∼ 30% too low at 4.8 MeV). In particular, we find that our current results are consistent with a set of correction factors which were first suggested 20 years ago, but have gone largely ignored until now. Our validation of these little known correction factors will have bearing on experiments which use the 66 Ga radioisotope to extrapolate absolute detector efficiencies to higher energies. In particular, we discuss the conclusions of a recent D(p, γ ) 3 He experiment which will be strongly affected by our current results. The astrophysical S -factor data derived from this D(p, γ ) 3 He experiment are now seen to be systematically too low by ∼ 30%.

Observation of p-wave capture strength in the 2H(d, γ)4He reaction at Ed= 80−0 keV

Abstract The 2 H ( d , γ 4 He reaction has been studied using tensor polarized deuterons having an incident energy of E d (lab) = 80 keV, which were stopped in the target. The angular distributions of the cross section σ ( θ )/ A 0 , vector analyzing power A y ( θ ), and tensor analyzing power A yy ( θ ) were measured and were interpreted using a model independent transition-matrix element analysis. These results lead to the conclusion that over 50% of the cross section strength at these low energies is due to p-wave E1 and M2 capture, is sharp contrast to previous assumptions of dominant s-wave E2 capture.

A portable 17.3 MeV gamma-ray source

Abstract The 7 Li(p, γ) 8 Be reaction at low beam energies, ≤ 100 keV, is considered for use as a high energy gamma-ray source. Production rates indicate that this reaction would yield a reasonable intensity of 17.3 and 14.3 MeV gamma rays with inexpensive and readily available proton ion sources.

Effects of non-nucleonic degrees of freedom in the {ital D}({ital p{searrow}{bold ,}}{bold {gamma}}){sup {bold 3}}{ital H}{ital e} and {ital p}({ital d{searrow}{bold ,{gamma}}}{bold )}{sup {bold 3}}{ital H}{ital e} reactions

Measurements of the D({ital p}{searrow},{gamma}){sup 3}He and {ital p}({ital d}{searrow},{gamma}){sup 3}He reactions below {ital E}{sub {ital p},{ital d}}=80 keV are compared to the results of calculations based on correlated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and a nuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interaction currents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an {ital S}-factor value of {ital S}({ital E}=0)=0.165{plus_minus}0.014 eVb, in reasonable agreement with theory. {copyright} {ital 1996 The American Physical Society.}Measurements of the D(p-->, gamma )3He and p(d-->, gamma )3He reactions below Ep,d = 80 keV are compared to the results of calculations based oncorrelated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and anuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interactioncurrents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an S-factor value of S(E= 0) = 0.165z0.014 eV b, in reasonable agreement with theory.

Effects of non-nucleonic degrees of freedom in the D(p

Measurements of the D({ital p}{searrow},{gamma}){sup 3}He and {ital p}({ital d}{searrow},{gamma}){sup 3}He reactions below {ital E}{sub {ital p},{ital d}}=80 keV are compared to the results of calculations based on correlated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and a nuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interaction currents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an {ital S}-factor value of {ital S}({ital E}=0)=0.165{plus_minus}0.014 eVb, in reasonable agreement with theory. {copyright} {ital 1996 The American Physical Society.}Measurements of the D(p-->, gamma )3He and p(d-->, gamma )3He reactions below Ep,d = 80 keV are compared to the results of calculations based oncorrelated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and anuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interactioncurrents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an S-factor value of S(E= 0) = 0.165z0.014 eV b, in reasonable agreement with theory.

Effects of Non-nucleonic Degrees of Freedom in theD(p→,γ)H3eandp(d→,γ)H3eReactions

Measurements of the D({ital p}{searrow},{gamma}){sup 3}He and {ital p}({ital d}{searrow},{gamma}){sup 3}He reactions below {ital E}{sub {ital p},{ital d}}=80 keV are compared to the results of calculations based on correlated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and a nuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interaction currents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an {ital S}-factor value of {ital S}({ital E}=0)=0.165{plus_minus}0.014 eVb, in reasonable agreement with theory. {copyright} {ital 1996 The American Physical Society.}Measurements of the D(p-->, gamma )3He and p(d-->, gamma )3He reactions below Ep,d = 80 keV are compared to the results of calculations based oncorrelated hyperspherical harmonic wave functions obtained from realistic interactions with full inclusion of Coulomb distortion in the initial continuum state, and anuclear current operator with one- and two-body components. Dramatic effects due to the tensor force and the associated two-body (meson-exchange) interactioncurrents are observed in the vector and, to some extent, tensor analyzing powers for the first time. The extrapolation to zero energy leads to an S-factor value of S(E= 0) = 0.165z0.014 eV b, in reasonable agreement with theory.

A polarimeter for low-energy protons

Abstract A polarimeter is described for proton beam energies below 100 keV using the 7 Li(p, γ) 8 Be reaction. Measurements indicate an analyzing power near 0.4 with yields that would allow a 10% measurement of beam polarization in 1 h for sources producing beam currents on the order of 30 μA.

Observation of substantial p-wave capture strength in the 7Li(p

The [sup 7]Li([ital [rvec p]],[gamma])[sup 8]Be reaction has been studied using polarized protons having an incident energy in the range [ital E][sub [ital p]](lab)=80--0 keV. The measured angular distributions of the cross section [sigma]([theta])/[ital A][sub 0] and analyzing power [ital A][sub [ital y]]([theta]) were interpreted using a model independent transition-matrix element analysis. The large ([similar to]40%) analyzing power at 90[degree] indicates the presence of an appreciable [ital p]-wave capture strength at these energies. The direct capture model is used to show that this could reduce the astrophysical [ital S] factor by as much as 40%.

Observation of Substantialp-Wave Capture Strength in theLi7(p→,γ)8BeReaction forEp=80−0keV and Implications for AstrophysicalSFactors

The [sup 7]Li([ital [rvec p]],[gamma])[sup 8]Be reaction has been studied using polarized protons having an incident energy in the range [ital E][sub [ital p]](lab)=80--0 keV. The measured angular distributions of the cross section [sigma]([theta])/[ital A][sub 0] and analyzing power [ital A][sub [ital y]]([theta]) were interpreted using a model independent transition-matrix element analysis. The large ([similar to]40%) analyzing power at 90[degree] indicates the presence of an appreciable [ital p]-wave capture strength at these energies. The direct capture model is used to show that this could reduce the astrophysical [ital S] factor by as much as 40%.