It is well known that the enhancement of halo neutron removal cross sections in neutron halo nuclei. This is one of the evidence for the neutron halo structure. Because the valence neutron of the ...isomeric state in
16
N is considered to be mainly occupying in the
s
-orbital, we studied the nuclear structure of
16
N as a candidate for neutron halo nucleus. In this study, we measured one-neutron removal cross sections
σ
-
1
n
using secondary beams of
16
N with a mixture of ground and isomeric states. We used two types of primary beams,
15
N and
18
O, to produce
16
N beams with different isomeric ratios (8.7, 24.2a
16
N beam with a large isomeric ratio is large compared to that obtained with another beam with a small isomeric state. This result suggests that the
16
N isomeric state is considered to have a neutron-halo-like structure.
Production cross sections of residual nuclei obtained by knockout and fragmentation reactions of different tin isotopes accelerated at 1A GeV have been measured with the fragment separator (FRS) at ...GSI, Darmstadt. The new measurements are used to investigate the neutron-excess dependence of the neutron- and proton-knockout cross sections. These cross sections are compared toGlauber model calculations coupled to a nuclear de-excitation code in order to investigate the role of the remnant excitations. This bench marking shows an overestimation of the cross sections for the removal of deeply bound nucleons. A phenomenological increase in the excitation energy induced in the remnants produced in these cases allows us to reproduce the measured cross sections.
•We have designed the EFCC for a correction of magnetic error fields in JT-60SA.•Error fields from TF/PF coils are 0.34mT as calculated by Monte-Carlo approach.•Required EFCC current to correct error ...fields is evaluated by a least square method.•The EFCC current of 45kA is required to reduce error field less than 0.1mT.•EFCC enables to produce stochastic magnetic structures at the edge region.
We have designed in-vessel coils for a correction of magnetic error fields in JT-60SA. In order to design the in-vessel coils, namely, error field correction coils (EFCCs), error fields from several sources such as manufacturing and assembly errors of superconducting coils are calculated by Monte-Carlo approach. Required EFCC currents to correct error fields are evaluated by a least square method. Additionally, by the field line tracing, it is found that resonant magnetic perturbations (RMPs) by the EFCC enable to produce stochastic magnetic structures at the edge region, that is applicable to an ELM control.
Absolute differential cross sections for elastic p7Be and p8B small-angle scattering were measured in inverse kinematics at an energy of 0.7 GeV/u at GSI Darmstadt. The hydrogen-filled ionization ...chamber IKAR was used as an active target to detect the recoil protons. The projectile tracking and isotope identification were performed with multi-wire proportional chambers and scintillation detectors. The measured cross sections were analysed using the Glauber multiple-scattering theory. The root-mean-square (rms) nuclear matter radii Rm=2.42(4) fm for 7Be and Rm=2.58(6) fm for 8B were obtained. The radial density distribution deduced for 8B exhibits a proton halo structure with the rms halo radius Rh=4.24(25) fm. A comparison of the deduced experimental radii is displayed with existing experimental and theoretical data.
Understanding the interactions and propagations of high energy protons and heavy ions are essential when trying to estimate the biological effects of Galactic Cosmic Rays (GCR) and Solar Particle ...Events (SPE) on personnel in space. To be able to calculate the shielding properties of different materials and radiation risks, particle and heavy ion transport codes are needed. In all particle and heavy ion transport codes, the probability function that a projectile particle will collide within a certain distance
x in the matter depends on the total reaction cross sections, and the calculated partial fragmentation cross sections scale with the total reaction cross sections. It is therefore crucial that accurate total reaction cross section models are used in the transport calculations. In this paper, different models for calculating nucleon–nucleus and nucleus–nucleus total reaction cross sections are compared with each other and with measurements. The uncertainties in the calculations with the different models are discussed, as well as their overall performances with respect to the available experimental data. Finally, a new compilation of experimental data is briefly presented.
•3D electromagnetic modelling of the JT60-SA tokamak has been carried out.•Frequency-domain electromagnetic characterization of active coils has been achieved.•Plasma response has been included so as ...to self-consistently study resistive wall modes with 3D conductors.
This paper reports the results of detailed 3D modelling of the JT60-SA tokamak. Different computational tools have been used, ranging from a purely electromagnetic description to models including the plasma response. Detailed 3D finite elements meshes have been developed, including key conducting structures of JT60-SA. The positive comparison of results produced with different assumptions and independent codes increases confidence in results. Frequency-domain electromagnetic characterization of active coils has been achieved, as well as resistive wall modes growth rate computation.
Summary Resonance frequency analysis (RFA) was introduced as a method for measuring implant stability more than a decade ago. Implant stability quotient (ISQ) values obtained using a recently ...introduced wireless RFA device have made it possible to evaluate stability in a non‐invasive technique; however, there are few studies of the factors that affect ISQ values determined using this device. The aim of the present study was to evaluate the association between ISQ values determined by wireless RFA and various factors related to dental implant stability using a pig cortical bone model. Dental implants (Replace® Select Tapered implants) with a length of 10 mm were placed into pig cortical bone samples, then, ISQ values were determined using wireless RFA under various conditions (probe orientation, diameter of implant, insertion torque and peri‐implant bone loss). The results of this study showed that ISQ values were not affected by the direction of the probe from parallel to perpendicular to the long axis of the pig bone or to the smart peg. In addition, the diameter of the implant did not have a significant effect on the measured ISQ values. Statistically significant correlations were found between insertion torque and ISQ values (Spearman’s test, P < 0·05), and lower ISQ values were observed for deeper peri‐implant vertical defects (Mann–Whitney U‐test, P < 0·05). A wireless RFA device appears to be useful for measuring implant stability within the limits of the present in vitro study.
The absolute differential cross section for small-angle proton elastic scattering on the proton-rich 8B nucleus has been measured in inverse kinematics for the first time. The experiment was ...performed using a secondary radioactive beam with an energy of 0.7 GeV/u at GSI, Darmstadt. The active target, namely hydrogen-filled time projection ionization chamber IKAR, was used to measure the energy, angle and vertex point of the recoil protons. The scattering angle of the projectiles was simultaneously determined by the tracking detectors. The measured differential cross section is analyzed on the basis of the Glauber multiple scattering theory using phenomenological nuclear-density distributions with two free parameters. The radial density distribution deduced for 8B exhibits a halo structure with the root-mean-square (rms) matter radius Rm=2.58(6) fm and the rms halo radius Rh=4.24(25) fm. The results on 8B are compared to those on the mirror nucleus 8Li investigated earlier by the same method. A comparison is also made with previous experimental results and theoretical predictions for both nuclei.
A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for 17−22N from charge changing cross section measurements around 900A MeV at GSI. ...Neutron halo effects are signalled for 22N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at N = 14 arising from the attractive proton–neutron tensor interaction, in good agreement with shell model calculations. Ab initio, in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon–nucleon and three-nucleon interaction reproduce well the data approaching the neutron drip-line isotopes but are challenged in explaining the complete isotopic trend of the radii.
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