S. Yen

Lifetime of 19 Ne * (4.03 MeV)

The Doppler-shift attenuation method was applied to measure the lifetime of the 4.03 MeV state in {sup 19}Ne. By utilizing a {sup 3}He-implanted Au foil as a target, the state was populated using the {sup 20}Ne({sup 3}He, {alpha}){sup 19}Ne reaction in inverse kinematics at a {sup 20}Ne beam energy of 34 MeV. De-excitation {gamma} rays were detected in coincidence with {alpha} particles. At the 1{sigma} level, the lifetime was determined to be 11{sub -3}{sup +4} fs and at the 95.45% confidence level the lifetime is 11{sub -7}{sup +8} fs.

Lifetimes of states in 19Ne above the 15O+α breakup threshold

The 15 O(α, γ) 19 Ne reaction plays a role in the ignition of type I x-ray bursts on accreting neutron stars. The lifetimes of states in 19 Ne above the 15 O+α threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in 19 Ne were populated in the 3 He( 20 Ne , α) 19 Ne reaction at a 20 Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler-shift attenuation method. The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise.