| 1. |
- Rudolph, D., et al.
(författare)
-
Experimental and shell-model study of excited states in 55Fe29 and related notes on 55Cu26
- 2021
-
Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 104:4
-
Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reaction 32S+28Si at 125-MeV beam energy was used to populate excited states in 55Fe. Combining the Gammasphere spectrometer with ancillary devices including the Microball CsI(Tl) array and a shell of neutron detectors, a comprehensive level scheme could be derived. The experimental results are compared with theoretical results from shell-model calculations. Taking into account isospin-symmetry breaking terms is found to considerably improve the shell-model description for 55Fe. This motivated a predictive case study of near-yrast states in the mirror nucleus 55Cu.
|
|
| 2. |
- Mukai, M., et al.
(författare)
-
In-gas-cell laser resonance ionization spectroscopy of Ir-196,Ir-197,Ir-198
- 2020
-
Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- Hyperfine structure (HFS) measurements of neutron-rich iridium isotopes Ir-196,Ir-197,Ir-198 (Z = 77, N = 119-121) were performed via in-gas-cell laser resonance ionization spectroscopy at the KEK Isotope Separation System. Magnetic dipole moments mu and isotope shifts were determined from the HFS spectra. The variation of mean-square charge radii and quadrupole deformation parameters of these isotopes were evaluated from the isotope shifts. The mu value of (197)h, agreed with a theoretical value based on the strong coupling model, and the Ir nucleus was interpreted as prolately deformed by the theoretical calculations. The mu values of Ir-196,Ir-198 were also compared with semiempirical values calculated based on the strong coupling model. From the comparison, we can suggest the possible spin values of I-pi = 1,2(-) for Ir-196 and I-pi = 1(-) for Ir-198.
|
|
| 3. |
- Yordanov, Deyan T., et al.
(författare)
-
Structural trends in atomic nuclei from laser spectroscopy of tin
- 2020
-
Ingår i: Communications Physics. - : Springer Nature. - 2399-3650. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Tin is the chemical element with the largest number of stable isotopes. Its complete proton shell, comparable with the closed electron shells in the chemically inert noble gases, is not a mere precursor to extended stability; since the protons carry the nuclear charge, their spatial arrangement also drives the nuclear electromagnetism. We report high-precision measurements of the electromagnetic moments and isomeric differences in charge radii between the lowest 1/2(+), 3/2(+), and 11/2(-) states in Sn117-131, obtained by collinear laser spectroscopy. Supported by state-of-the-art atomic-structure calculations, the data accurately show a considerable attenuation of the quadrupole moments in the closed-shell tin isotopes relative to those of cadmium, with two protons less. Linear and quadratic mass-dependent trends are observed. While microscopic density functional theory explains the global behaviour of the measured quantities, interpretation of the local patterns demands higher-fidelity modelling. Measurements of the hyperfine structure of chemical elements isotopes provide unique insight into the atomic nucleus in a nuclear model-independent way. The authors present collinear laser spectroscopy data obtained at the CERN ISOLDE and measure hyperfine splitting along a long chain of odd-mass tin isotopes.
|
|
| 4. |
- Brennich, Martha, et al.
(författare)
-
Nanoparticle Characterization Methods : Applications of Synchrotron and Neutron Radiation
- 2016
-
Ingår i: Pharmaceutical Nanotechnology. - Weinheim, Germany : John Wiley & Sons. - 9783527340545 - 9783527800681 ; , s. 157-174
-
Bokkapitel (refereegranskat)abstract
- The characterization of materials at the atomic-, nano-, and microscales is of crucial importance in understanding and then tailoring their macroscale properties and function for end-use applications and for effective modern cradle-to-reuse materials cycling. Synchrotron light, as well as the complementary neutron beams, offer exquisite microscopy probes to look into the heart of materials. This chapter presents some examples of pharma-oriented nanoparticle characterization highlighting the possibilities of synchrotron light and neutron beams. Small-angle X-ray scattering (SAXS) is a well-established technique to probe nanoscale structures. SAXS can also deliver valuable information on the structure of self-assembled nanovectors, such as liposomes, which are recognized as efficient platforms for drug delivery. Future developments for neutron characterization will be driven in parallel with instrumental developments at existing sources and future facilities such as the European Spallation Source (ESS) being built in Sweden.
|
|
| 5. |
- Ekman, Jörgen, et al.
(författare)
-
Mirror Symmetry in the Upper fp Shell
- 2005
-
Ingår i: Modern Physics Letters A. - : World Scientific Publishing. - 0217-7323 .- 1793-6632. ; 20:39, s. 2977-2992
-
Forskningsöversikt (refereegranskat)abstract
- A detailed investigation of the contribution from Coulomb effects to the observed mirror energy difference diagrams in nuclei in the lower part of the upper fp shell is presented by means of large-scale shell-model calculations.
|
|
| 6. |
- Forslind, B, et al.
(författare)
-
Assessment of Qualitative and Quantitative Data From Pathological Hairs : A Critical-evaluation of Scanning Electron-microscope and Proton-induced X-ray-emission Analyses
- 1987
-
Ingår i: Scanning Microscopy. - : Scanning Microscopy Int. - 0891-7035. ; 1:1, s. 159-167
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of single hair fibres in genetic disorders is a desirable complement to the clinical diagnosis. The scanning electron microscope (SEM) allows detailed study of the surface morphology of hair fibres which may explain some mechanical characteristics of the pathological hair. Quantitative elemental data may indicate biochemical or metabolic abnormalities. In this preliminary study we assess the feasibility of combining SEM and proton induced X-ray emission (PIXE) analysis on single hair fibres from 12 cases of genetic disease influencing the integument status. We conclude that SEM is a valuable tool in the analysis of hair pathology. The macro-PIXE technique involves some methodological and technical problems which in many cases are likely to be solved by using a proton microbeam. However, this means that routine methods have to be abandoned and careful selection of the material for analysis is an imperative necessity.
|
|
| 7. |
- Ghetti, R, et al.
(författare)
-
Influence of cross-talk rejection procedures on two-neutron intensity interferometry.
- 1999
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 421:3, s. 542-551
-
Tidskriftsartikel (refereegranskat)abstract
- This work investigates the effects of a cross-talk rejection procedure on the two-neutron correlation function. The rejection method relies only upon simple kinematic relations between the energy of the detected neutrons and can be applied to commonly used detector configurations. It is demonstrated that the comparison of a cross-talk corrected correlation function with the theory is meaningful as long as the cross-talk rejection procedure and the response of the detector filter are consistently incorporated into the theoretical calculations.
|
|
| 8. |
- Ghetti, Roberta, et al.
(författare)
-
Particle emission time sequence in intermediate energy heavy ion reactions
- 2003
-
Ingår i: Nuclear Physics, Section A. - 0375-9474 .- 1873-1554. ; 721, s. 313-316
-
Tidskriftsartikel (refereegranskat)abstract
- The CHIC Collaboration has performed a series of simultaneous pp, np and nn fermion interferometry experiments in order to study the space-time evolution of the emission sources in intermediate energy heavy ion reactions. Furthermore, when correlations of non-identical particles are available, additional model independent information on the emission chronology of the particles is obtained. In this contribution, after reviewing the method to determine the order of emission of non-identical particles, we discuss the emission chronology of neutrons and protons from the E/A = 45 MeV Ni-58 + Al-27 reaction and from the E/A = 60 MeV Ar-36 + Al-27 reaction, shown here for the first time.
|
|
| 9. |
|
|
| 10. |
- Hinde, D. J., et al.
(författare)
-
Experimental investigation of the role of shell structure in quasifission mass distributions
- 2022
-
Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 106:6
-
Tidskriftsartikel (refereegranskat)abstract
- Background: To understand superheavy element synthesis reactions, quantifying the role of quantum shells in quasifission dynamics is important. In reactions with actinide nuclides, a wide peak in the binary quasifission mass yield is seen, centered close to the 208Pb mass. It is generally attributed to the 208Pb spherical closed shells causing a valley in the potential-energy surface, attracting flux to these mass splits. However, an early experiment studying 48Ca, 50Ti+238U reactions showed strong evidence that sequential fission plays an important role in generating the observed peak. These conflicting interpretations have not been resolved up to now.Purpose: This work aims to measure quasifission mass spectra for reactions with nuclei lighter than 208Pb, having negligible sequential fission, to search for systematic features correlated with the proton shells known to affect low-energy fission mass distributions of the same actinide elements.Methods: Systematic measurements have been made at energies near and below the capture barriers (where quasifission is most prominent) of mass-angle distributions for fission following collisions of 48Ti projectiles with even-even nuclides from 154Sm to 200Hg. Mean excitation energies above the ground-states ranged from 51 to 33 MeV, respectively.Results: With increasing compound nucleus atomic number ZCN, a rapid transition occurs from fission having characteristics of fusion-fission to fast quasifission. The heaviest reactions form 240Cf, 244Fm, and 248No. Low -energy fission of neighboring isotopes is mass asymmetric, correlated with proton number Z = 56. However, peak quasifission yields are at mass-symmetry for all reactions. There appears to be a very small (P-3%) systematic excess of yield correlated with Z = 56, however this is at the limit of sensitivity of the experiment.Conclusions: No significant (>3%) systematic features are seen in the quasifission mass spectra that can be unambiguously identified as resulting from shells. This small influence may result from attenuation of shell effects due to the excitation energy introduced, even in these near-barrier reactions giving low excitation energies typical of superheavy element synthesis reactions.
|
|
