[en] The single-neutron adding (d,p) reaction has been performed on ¹³⁶Xe in inverse kinematics at 10 MeV/u. The position, time-of-flight, and energy of the outgoing protons were analyzed by the new helical orbit spectrometer, HELIOS, at Argonne National Laboratory. An excitation-energy resolution of ≤ 100 keV was obtained in the outgoing proton spectra. The experimental setup is described, along with a technique of extracting absolute cross sections. Data are shown which illustrate the performance of the device. This measurement clearly demonstrates the potential of HELIOS for future heavy radioactive-beam studies.

[en] We have studied the nucleus "1"4B using the "1"3B(d,p)"1"4B and "1"5C(d,"3He)"1"4B reactions in inverse kinematics using HELIOS. HELIOS (helical orbit spectrometer) is a device specifically designed to study reactions in inverse kinematics at the ATLAS facility at Argonne National Laboratory. The two reactions provide complementary information about the negative-parity 1s_1_/_2 and 0d_5_/_2 neutron single-particle states in "1"4B. The results indicate that the ground and first-excited states are largely dominated by 1s_1_/_2 neutron configuration. The data from the (d,p) reaction give neutron-spectroscopic strengths for 1s_1_/_2 and 0d_5_/_2 levels, and the (d,"3He) results confirm the existence of a broad 2"- excited state suggested in the literature. Together these results provide estimates of the sd-shell neutron effective single-particle energies in "1"4B

[en] Type I X-ray bursts are the most common explosions in the Galaxy; however, the nucleosynthesis that occurs during the thermonuclear runaway and explosion is poorly understood. In this proceedings we discuss current experimental efforts and techniques that are being used to study X-ray burst nucleosynthesis in the laboratory. Specifically, radioactive ion beam techniques that have recently been developed have allowed the study of some of the most important (α, p) reactions in X-ray bursts for the first time.

[en] The helical orbit spectrometer, HELIOS, at Argonne National Laboratory has been developed to measure transfer reactions in inverse kinematics with good Q-value resolution. The technique is discussed alongside examples of measurements with medium-mass beams, the first exploration of reactions in the the forward hemisphere, and a future outlook.

[en] The single-neutron properties of the N=83 nucleus ¹³⁷Xe have been studied using the ¹³⁶Xe(d,p) reaction in inverse kinematics at a beam energy of 10 MeV/u. The helical-orbit spectrometer, HELIOS, at Argonne National Laboratory was used to analyze the outgoing protons, achieving an excitation-energy resolution of ∼100 keV. Extraction of absolute cross sections, angular distributions, and spectroscopic factors has led to a more complete understanding of the single-neutron strength in ¹³⁷Xe. In particular, the centroids of the νh_9/2 and νi_13/2 strengths appear to evolve through the N=83 isotones in a manner consistent with the action of the tensor force.

[en] The structure of ¹⁵C, with an s_1/2 neutron weakly bound to a closed-neutron shell nucleus ¹⁴C, makes it a prime candidate for a one-neutron halo nucleus. We have for the first time studied the cross section for the fusion-fission reaction ¹⁵C+²³²Th at energies in the vicinity of the Coulomb barrier and compared it to the yield of the neighboring ¹⁴C+²³²Th system measured in the same experiment. At sub-barrier energies, an enhancement of the fusion yield by factors of 2-5 was observed for ¹⁵C, while the cross sections for ¹⁴C match the trends measured for ^12,13C.

[en] We have for the first time studied the fusion-fission excitation functions for the systems ^14,15C + ²³²Th at energies in the vicinity of the Coulomb barrier. At energies below the barrier, the fusion cross section of the halo nucleus ¹⁵C showed an enhancement by a factor of 2-5, while the fusion cross section for ¹⁴C shows a similar trend to that of ^12,13C. The fusion-fission cross section below the Coulomb barrier shows an enhancement by a factor of 5 compared to ^12,13,14C. A measurement of the transfer cross sections in ¹⁵C + Th²³² may help in understanding the effects which lead to the observed enhancement