Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNeutron inelastic scattering measurements on $^{136}$Xe at $E_{n}$ = 0.7 to 100 MeV
98
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Experiments searching for neutrinoless double beta decay ($0 ubetabeta$) require precise energy calibration and extremely low backgrounds. One of the most popular isotopes for $0 ubetabeta$ experiments is $^{136}$Xe. In support of these experiments, the neutron inelastic scattering properties of this isotope have been measured at the GErmanium Array for Neutron Induced Excitations (GEANIE) at the Los Alamos Neutron Science Center. Time-of-flight techniques are utilized with high-purity germanium detectors to search for inelastic scattering $gamma$ rays for neutron energies between 0.7 and 100 MeV. Limits are set on production of yet-unobserved $gamma$ rays in the energy range critical for $0 ubetabeta$ studies, and measurements are made of multiple $gamma$-ray production cross sections. In particular, we have measured the production of the 1313 keV $gamma$ ray which comes from the transition of the first-excited to ground state of $^{136}$Xe. This neutron-induced $gamma$ line may be useful for a novel energy calibration technique, described in this paper.
rate research
Read More
The $ u0h_{9/2}$ and $ u0i_{13/2}$ strength at $^{137}$Xe, a single neutron outside the $N=82$ shell closure, has been determined using the $^{136}$Xe($alpha$,$^3$He)$^{137}$Xe reaction carried out at 100 MeV. We confirm the recent observation of the second 13/2$^+$ state and reassess previous data on the 9/2$^-$ states, obtaining spectroscopic factors. These new data provide additional constraints on predictions of the same single-neutron excitations at $^{133}$Sn.
Moller scattering is one of the most fundamental processes in QED. Understanding it to high precision is necessary for a variety of modern nuclear and particle physics experiments. In a recent calculation, existing soft-photon radiative corrections were combined with new hard-photon bremsstrahlung calculations to take into account the effect of photon emission at any photon energy, where the electron mass was included at all steps. To test the calculation, an experiment was carried out using the 3 MV Van de Graaff electrostatic accelerator at the MIT High Voltage Research Laboratory. Momentum spectra at three scattering angles at an incident electron energy of 2.5 MeV are reported here, and compared to the simulated radiative Moller spectra, based on our previous calculation. Good agreement between the measurements and our calculation is observed in the momentum spectrum at the three angles.
Background: Double charge exchange (DCE) nuclear reactions have recently attracted much interest as tools to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-beta decay. In this framework, a good description of the reaction mechanism and a complete knowledge of the initial and final-state interactions are mandatory. Presently, not enough is known about the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for future DCE studies. Among these, the 20Ne + 76Ge DCE reaction is particularly relevant due to its connection with 76Ge double-beta decay. Purpose: We intend to characterize the initial-state interaction for the 20Ne + 76Ge reactions at 306 MeV bombarding energy and determine the optical potential and the role of the couplings between elastic channel and inelastic transitions to the first low-lying excited states. Methods: We determine the experimental elastic and inelastic scattering cross-section angular distributions, compare the theoretical predictions by adopting different models of optical potentials with the experimental data, and evaluate the coupling effect through the comparison of the distorted-wave Born approximation calculations with the coupled channels ones. Results: Optical models fail to describe the elastic angular distribution above the grazing angle (9.4{deg}). A correction in the geometry to effectively account for deformation of the involved nuclear systems improves the agreement up to about 14{deg}. Coupled channels effects are crucial to obtain good agreement at large angles in the elastic scattering cross section.
New measurements of the neutron-neutron quasifree scattering cross section in neutron-deuteron breakup at an incident neutron energy of 10.0 MeV are reported. The experiment setup was optimized to evaluate the technique for determining the integrated beam-target luminosity in neutron-neutron coincidence cross-section measurements in neutron-deuteron breakup. The measurements were carried out with a systematic uncertainty of $pm 5.6 %$. Our data are in agreement with theoretical calculations performed using the CD-Bonn nucleon-nucleon potential in the Faddeev formalism. The measured integrated cross section over the quasifree peak is $20.5 pm 0.5 text{(stat)} pm 1.1 text{(sys)}$ mb/sr$^2$ in comparison with the theory prediction of 20.1 mb/sr$^{2}$. These results validate our technique for determining the beam-target luminosity in neutron-deuteron breakup measurements.
The neutron and its hypothetical mirror counterpart, a sterile state degenerate in mass, could spontaneously mix in a process much faster than the neutron $beta$-decay. Two groups have performed a series of experiments in search of neutron - mirror-neutron ($n-n$) oscillations. They reported no evidence, thereby setting stringent limits on the oscillation time $tau_{nn}$. Later, these data sets have been further analyzed by Berezhiani et al.(2009-2017), and signals, compatible with $n-n$ oscillations in the presence of mirror magnetic fields, have been reported. The Neutron Electric Dipole Moment Collaboration based at the Paul Scherrer Institute performed a new series of experiments to further test these signals. In this paper, we describe and motivate our choice of run configurations with an optimal filling time of $29~$s, storage times of $180~$s and $380~$s, and applied magnetic fields of $10~mu$T and $20~mu$T. The choice of these run configurations ensures a reliable overlap in settings with the previous efforts and also improves the sensitivity to test the signals. We also elaborate on the technique of normalizing the neutron counts, making such a counting experiment at the ultra-cold neutron source at the Paul Scherrer Institute possible. Furthermore, the magnetic field characterization to meet the requirements of this $n-n$ oscillation search is demonstrated. Finally, we show that this effort has a statistical sensitivity comparable to the current leading constraints for $n-n$ oscillations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
