P. Aguer

New measurement and analysis of the7Be(p,γ)8B cross section

Cross sections for the 7Be(p,γ)8B reaction have heen measured for Ec.m. = 0.35-1.4 MeV using radioactive 7Be targets. Two independent measurements carried out with different beam conditions, different targets, and detectors are in excellent agreement. A statistical comparison of these measurements with previous results leads to a restricted set of consistent data. The deduced zero-energy S factor S(0) is found to be 15%-20% smaller than the previously recommended value. This implies a 8B solar neutrino flux lower than previously predicted in various standard solar models.

Low-energy measurement of the 7Be(p,gamma)8B cross section.

We have measured the cross section of the 7Be(p,gamma)8B reaction for E(c.m.) = 185.8, 134.7, and 111.7 keV using a radioactive 7Be target (132 mCi). Single and coincidence spectra of beta+ and alpha particles from 8B and 8Be* decay, respectively, were measured using a large acceptance spectrometer. The zero energy S factor inferred from these data is 18.5+/-2.4 eV b and a weighted mean value of 18.8+/-1.7 eV b (theoretical uncertainty included) is deduced when combining this value with our previous results at higher energies.

Hydrogen burning of O-17 in classical novae

We report on the observation of a previously unknown resonance at E{sub R}{sup lab}=194.1{+-}0.6 keV in the {sup 17}O(p,{alpha}){sup 14}N reaction, with a measured resonance strength {omega}{gamma}{sub p{alpha}}=1.6{+-}0.2 meV. We studied in the same experiment the {sup 17}O(p,{gamma}){sup 18}F reaction by an activation method and the resonance-strength ratio was found to be {omega}{gamma}{sub p{alpha}}/{omega}{gamma}{sub p{gamma}}=470{+-}50. The corresponding excitation energy in the {sup 18}F compound nucleus was determined to be 5789.8{+-}0.3 keV by {gamma}-ray measurements using the {sup 14}N({alpha},{gamma}){sup 18}F reaction. These new resonance properties have important consequences for {sup 17}O nucleosynthesis and {gamma}-ray astronomy of classical novae.

Experimental Study of 17O(p,α)14N and 17O(p,γ)18F for Classical Nova Nucleosynthesis

We investigated the proton‐capture reactions on 17O occuring in classical nova explosions. We observed a previously undiscovered resonance at ERlab=194.1±0.6u2009keV in the 17O(p,α)14N reaction, with a measured resonance strength ωγpα=1.6±0.2 meV. We studied in the same experiment the 17O(p,γ)18F reaction by an activation method and the resonance‐strength ratio was found to be ωγpα/ωγpγ=470±50. The corresponding excitation energy in the 18F compound nucleus was determined to be 5789.8±0.3 keV by γ‐ray measurements using the 14N(α,γ)18F reaction. These new resonance properties have important consequences for 17O nucleosynthesis and γ‐ray astronomy of classical novae.

Hydrogen Burning ofO17in Classical Novae

We report on the observation of a previously unknown resonance at E{sub R}{sup lab}=194.1{+-}0.6 keV in the {sup 17}O(p,{alpha}){sup 14}N reaction, with a measured resonance strength {omega}{gamma}{sub p{alpha}}=1.6{+-}0.2 meV. We studied in the same experiment the {sup 17}O(p,{gamma}){sup 18}F reaction by an activation method and the resonance-strength ratio was found to be {omega}{gamma}{sub p{alpha}}/{omega}{gamma}{sub p{gamma}}=470{+-}50. The corresponding excitation energy in the {sup 18}F compound nucleus was determined to be 5789.8{+-}0.3 keV by {gamma}-ray measurements using the {sup 14}N({alpha},{gamma}){sup 18}F reaction. These new resonance properties have important consequences for {sup 17}O nucleosynthesis and {gamma}-ray astronomy of classical novae.