Estimation of the NiCu Cycle Strength and Its Impact on Type I X-Ray Bursts

Type I X-ray bursts (XRBs) are powered by thermonuclear burning on proton-rich unstable nuclides. The construction of burst models with accurate knowledge of nuclear physics is required to properly interpret burst observations. Numerous studies that have investigated the sensitivities of burst models to nuclear inputs have commonly extracted the strength of the NiCu cycle in the rp process, determined by the Cu-59(p,alpha)Ni-56 and Cu-59(p,gamma)Zn-60 thermonuclear reaction rates, as critical in the determination of reaction flow in the burst. In this study, the strength of the cycle at the XRB temperature range was estimated based on published experimental data. The nuclear properties of the compound nucleus Zn-60 were evaluated for the Cu-59(p,alpha)Ni-56 and Cu-59(p,gamma)Zn-60 reaction rate calculations. Monte Carlo rate calculations were conducted to include the large uncertainties of nuclear properties in the calculations. In the current work, a weak NiCu cycle is expected, whereas the rates adopted by the previous studies suggest a strong NiCu cycle. Model simulations were performed with the new rates to assess the impact on Type I XRBs. The results show that the estimated cycle strength does not strongly influence the model predictions of the burst light curve or synthesized abundances

Study on the application of SiPM to γ ray and charged particle measurement using scintillation crystals

The characteristics of a Silicon Photo Multiplier (SiPM)-based scintillation detector system were studied. The influence of the bias voltage and the number of SiPMs on the energy resolution was identified. The single SiPM energy spectra in the multi-SiPM system showed their dependency on the position of the 60Co radiation source. The application of geometric mean on the multi-SiPM system was also considered to bypass single channel calibrations. Preliminary results on the performances of developing scintillation detectors with a CsI(Tl) crystal or a plastic scintillator are demonstrated. The capability of charged particle measurement for CsI(Tl) crystal and sub-nanosecond timing resolution of plastic scintillator were identified. © 2023 Elsevier B.V.11Nsciescopu

Development and characterization of new position-sensitive silicon strip detectors

Direct reaction experiments in inverse kinematics are one of the best experimental tools to study a wide range of nuclear properties, providing a great probe into the nuclear structure of exotic nuclei and enabling the measurement of reactions relevant to many astrophysical scenarios. In order to fully exploit the next generation of radioactive ion beam facilities, a large amount of effort was devoted to developing nuclear detectors specially designed for direct reaction experiments. An instrumental part of these detector devices is the Micron X6 position-sensitive double sided silicon strip detector. This custom-made detector is segmented in 4 strips on its ohmic side and 8 resistive charge-splitting strips on its junction side, providing excellent position measurement of charged particles with a much smaller number of signals than traditional DSSSD with similar position resolution. © 2023 Elsevier B.V.11Nsciescopu

Development of the STARK detector for nuclear reaction studies

Silicon Telescope Array for Reaction studies in inverse Kinematics, STARK, is under development at the Center for Exotic Nuclear Studies to perform nuclear reaction experiments including elastic scattering and neutron transfer reaction. The array consists of 40 double-sided, resistive silicon strip detectors and 12 single-sided, non-resistive strip detectors, and they form three rings covering a large angular range. The expected angular resolution is less than 1°, and the angular coverage of polar angles is 43–78° and 105–150° in the lab frame. The GET (General Electronics for Time projection chamber project) electronics system is used to handle about 1000 channels from detectors. Several elastic scattering experiments are considered as the commissioning of the STARK at KoBRA in the early stage of RAON. © 2023 Elsevier B.V.11Nsciescopu

TexAT detector upgrade for 14O(α,p)17F cross section measurement

A direct cross-section measurement of the 14O(α,p)17F reaction is important to understand the light curves of x-ray bursts. The measurement will be performed using the Texas Active Target TPC version 2 (TexAT_v2). The TexAT_v2 aims at measuring lower energy protons from the reaction than the original TexAT. Newly developed silicon and CsI(Tl) detector arrays are added at the left, right and bottom of a modified field cage to increase its detection efficiency. This paper describes the overall specifications and two commissioning experiments performed at Texas A&M University.11Nsciescopu

Direct measurement of the

Several (α, p) reactions with radioactive-ions (RI) in the αp-process are important to characterize X-ray bursts. However, some of them do not have sufficient experimental data, and the 26Si(α, p)29P reaction is one of such reactions. We performed a direct measurement of the reaction in inverse kinematics with a thick target at the CNS RI beam separator (CRIB).We used a multiplexer circuit, Mesytec MUX, to acquire data from many channels of silicon detectors. In this experimental setup, a resonant elastic scattering was measured simultaneously. The details of the experimental conditions and the preliminary results of the analysis are discussed

X-ray burst studies with the JENSA gas jet target

When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the αp-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 ∼1019 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34Ar(α, p)37 K reaction at NSCL

X-ray Burst Studies with the JENSA Gas Jet Target

When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the αp-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 ∼1019 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34Ar(α, p)37 K reaction at NSCL

X-ray burst studies with the JENSA gas jet target

When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the αp-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 ∼1019 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34Ar(α, p)37 K reaction at NSCL