X-ray burst studies with the JENSA gas jet target

K Schmidt ,Orlando Gomez,Eunji Lee,Sara Ayoub,Rebecca Toomey,U Greife ,K Y Chae ,K Smith ,M R Hall ,K L Jones ,Z Meisel ,Natã F Soares De ,R L Kozub ,P D O’malley ,D W Bardayan ,C M Deibel ,L E Linhardt ,Wei Jia Ong,P Thompson ,A Sachs ,K T Schmitt ,K A Chipps ,Sung‐Hoon Ahn ,H Schatz ,S D Pain ,J C Blackmon ,M S Smith ,D Blankstein ,A Kontos ,F Montes ,A Lepailleur ,E Deleeuw ,J Allen ,J A Cizewski ,J Browne ,S.m Cha ,U Hager ,M Matoš ,D Walter

doi:10.1051/epjconf/201716501043

Abstract

When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the α p-process as a break out mechanism from the hot CNO cycle. Model calculations predict ( α , p) reaction rates significantly affect both the light curves and elemental abundances in the burst ashes. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target enables the direct measurement of previously inaccessible ( α ,p) reactions with radioactive beams provided by the rare isotope re-accelerator ReA3 at the National Superconducting Cyclotron Laboratory (NSCL), USA. JENSA is going to be the main target for the Recoil Separator for Capture Reactions (SECAR) at the Facility for Rare Isotope Beams (FRIB). Commissioning of JENSA and first experiments at Oak Ridge National Laboratory (ORNL) showed a highly localized, pure gas target with a density of ∼10 19 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34 Ar( α , p) 37 K reaction at NSCL.

Highlights

A type I X-ray burst occurs when a neutron star accretes material from the outer layers of its binary companion
In order to investigate discrepancies between theoretical calculations and indirect measurements, a direct study of the 34Ar(α, p)37K reaction in inverse kinematics has been performed at the National Superconducting Cyclotron Laboratory (NSCL)
Upstream SuperORRUBA is composed of six single Micron style BB15 silicon detectors of 1-mm thickness

Summary

Introduction

A type I X-ray burst occurs when a neutron star accretes material from the outer layers of its binary companion. In order to study the influence of the 34Ar(α, p)37K reaction, its nominal rate has been decreased and increased by a factor 100 in a single-zone X-ray burst calculation with an initial hydrogen abundance of 0.5.

Results

Conclusion