The ¹⁷F(α, p)²⁰Ne Reaction Rate in Type I X-Ray Bursts from the Inverse Reaction

The ¹⁷F(α, p)²⁰Ne reaction has been identified as an alternate pathway for

breakout from the hot-CNO cycle that can be important in some X-ray burst

scenarios. We have previously measured the ²⁰Ne(p, α)¹⁷F cross section at low

center-of-mass energies ranging from 4.80 to 7.60 MeV via activation

measurements with a proton beam on a ²⁰Ne gas cell at the Fox Accelerator

Laboratory at Florida State University. We subsequently measured the same

reaction through inverse kinematics with a ²⁰Ne beam on a methylene target

at Argonne National Lab’s ATLAS facility. We used an annular Si strip

detector for alpha-particle detection with recoiling heavy ions detected in the

Enge spectrograph by the MONICA focal plane detector. Studying the

reaction in inverse kinematics allows us to distinguish alpha particles emitted

to the first-excited state of ¹⁷F which do not contribute to the reverse (α, p)

reaction on the ¹⁷F ground state. Cross section comparisons and preliminary

results from an R-matrix analysis constraining properties of states in ²¹Na will

be presented.