Metastable iron carbide thin films (χ-Fe5C2 and o-Fe7C3) were produced by pulsed laser deposition of Fe in a CH4 atmosphere, and their Mossbauer spectra and X-ray diffraction patterns were measured. Films consisting of amorphous Fe-C carbide were obtained when the substrate temperature was kept at 300 K during deposition, while crystalline films were produced for a substrate temperature of 573 K. The effect of CH4 pressure was investigated. Films produced below 4.0 Pa consisted of a combination of χ-Fe5C2 and α-Fe, and single-phase carbide films were produced at higher pressure: pure χ-Fe5C2 and o-Fe7C3 films were produced at 4.0 and 6.0 Pa, respectively. At 13 Pa, a film was produced consisting of o-Fe7C3 and paramagnetic amorphous Fe-C containing a large amount of C atoms. The film produced at the highest pressure of 40 Pa consisted solely of paramagnetic amorphous Fe-C.

Fe doped FTO powders were prepared by a chemical precipitation method. Mossbauer spectra of FTO with several concentrations of Fe dopants were decomposed into two doublets (D1 and D2). A doublet with a small electric field gradient (D1) is assigned to Fe3+ in a small distorted site of the rutile structure, and another doublet (D2) to Fe3+ in a large distorted site due to F− ion and oxygen defect. Furthermore, with increase of the annealing temperature the isomer shifts tended to decrease. It suggests that Fe3+ bonds are more covalently bonded than ionic at the higher annealing temperatures. The surface layer of grains were also characterized by 57Fe CEMS. The defect structures of Fe doped FTO were estimated using the oxygen defect models of tin oxide [Mudarra Navarro et al., J. Phys. Chem. C, 119, 5596 (2015)].

The β-ray detected nuclear magnetic resonance (β-NMR) of a short lived-nucleus 17N (I = 1/2, T1/2 = 4.173 s) in liquid H2O and CH3NO2 has been performed. A π-pulse method was applied to obtain sharp NMR lines, from which the ratio of the Larmor frequencies of 17N in CH3NO2 and 1H was determined to be ν[17N in CH3NO2]/ν[1H2O] = 0.1265751 ± 0.0000019. Two resonance lines were observed for 17N in H2O with the relative frequency shifts of –(2.33 ± 0.37) × 10−4 and (2.91 ± 0.27) × 10−4 referenced to 17N in CH3NO2.

The second nearest-neighbor modified embedded atom method (2NN MEAM) is a semi-empirical simulation technique designed to calculate materials properties of metallic and covalent solids. It is a strong candidate for calculation of site occupation, defect association, and diffusion mechanisms in intermetallic compounds, which would provide a tool for interpreting experimental results and for predicting new, interesting measurements to perform. Potentials for 39 elements can be found in the literature, but cadmium, an important element for perturbed angular correlation spectroscopy (PAC), is absent. The purpose of this work was to develop a 2NN-MEAM potential for cadmium. Empirical parameters were determined through optimization of the potential’s ability to reproduce known physical properties of pure cadmium including cohesive energy, lattice parameters, elastic constants, structural enthalpy differences, surface enthalpy, vacancy formation energy, thermal expansion, and specific heat. Prospects for using this new potential with 2NN MEAM potentials for other elements to help interpret previous PAC studies of cadmium diffusion in intermetallic compounds will be discussed.

YFexCr(1-x)O3 (0 ≤ x ≤ 1) compounds prepared by autocombustion were studied with X-ray and neutron powder diffraction, Mossbauer spectroscopy and ab-initio electronic structure calculations to try to understand the interplay of magnetic order and structural parameters as a function of doping in this multiferroic material. All samples exhibit the orthorhombic nuclear structure (space group symmetry Pnma) and the cell parameters vary continuously as a function of doping. In the neutron powder diffraction patterns it was observed that in addition to the Pnma nuclear structure peaks reflections are seen in all samples which arise from magnetic order. These peaks can be indexed using the nuclear unit cell indicating an ordering vector of k = (0,0,0). Using representational analysis and Rietveld refinements the magnetic structure was determined to be Pn’ma’ and the mean magnetic moment per transition metal atom was observed to decrease continuously from Fe to Cr. For compounds with x > 0.25 a weak ferromagnetic contribution is also present which is due to a small canting of the moments out of the basal plane. The Mossbauer spectra corroborate the NPD results with all samples showing single magnetic sextets at 4.2 K. The energy gap and the main direct interband transition of the endmember samples were obtained by optical absorption measurements. These optical data were analyzed with the help of DFT band structure calculation using the GGA-PBE + U approximation.

J-PET is the first positron-emission tomograph (PET) constructed from plastic scintillators. It was optimized for the detection of photons from electron-positron annihilation. Such photons, having an energy of 511 keV, interact with electrons in plastic scintillators predominantly via the Compton effect. Compton scattering is at most probable at an angle orthogonal to the electric field vector of the interacting photon. Thus registration of multiple photon scatterings with J-PET enables to determine the polarization of the annihilation photons. In this contribution we present estimates on the physical limitation in the accuracy of the polarization determination of 511 keV photons with the J-PET detector.

We have newly developed 166Er Mossbauer spectroscopy in Institute for Integrated Radiation and Nuclear Science, Kyoto University (KURNS). As 166Ho radioactive source, HoAl2 was used. The compound was irradiated in the nuclear reactor (1 MW) for 5 min. The source has the intensity of 19 MBq and the half-life of 26.8 h. It is our privilege to conduct measurement immediately after the preparation of the radioactive source, since the spectroscopic equipment is situated just next to the reactor. The spectra of three typical Er oxides, Er2O3, ErFeO3, and ErMnO3 were measured at 40 K. On the basis of the calculated asymmetry parameter η and the evaluated sign of the quadrupole coupling constant e2qQ/2 from the structure parameters, we have successfully analyzed the spectra by using the quadrupole Hamiltonian assuming the transmission integral line shapes. The 166Er Mossbauer parameters, isomer shift IS, e2qQ/2, and line width W were obtained for the three specimens.

High-resolution monochromators for various nuclei have been developed at the nuclear resonant scattering beamline at SPring-8. In particular, monochromators for 57Fe are prepared with three different resolutions. The focusing optics of a Kirkpatrick-Baez mirror and compound refractive lenses have been installed in recent years. The available X-ray beam properties of the energy resolution and beam size at the transition energies of Mossbauer nuclei are summarized in this report.

There are various tests of the Standard Model aimed at probing new physics. One such test is to check the unitarity of the Cabbibo-Kobayashi-Masakawa matrix, with the most precise result given by the normalization of the top row. The precision of this result is limited by the uncertainty of the Vud and Vus elements. The most precise result for Vud is currently derived from the ensemble of superallowed 0+ → 0+ nuclear β decays, but the determination from other transitions is desirable to check theoretical calculations and the potential presence of unknown systematic contributions. Other candidates include neutron decay, pion decay, and the ensemble of nuclear mirror decays. While the neutron and pion decay present their own unique experimental challenges, the group of mirror decays require the precise determination of the Fermi to Gamow-Teller mixing ratio. This value can be extracted from a measurement of the β-ν angular correlation parameter, αβν, which is currently only known for five mirror decays. A new ion trapping system, St. Benedict (Superallowed Transition Beta-Neutrino Decay-Ion-Coincidence Trap), to be located in the Nuclear Science Laboratory at the University of Notre Dame is currently under construction and will ultimately aim to extract αβν for more mirror decays. The focus of this work is on simulations that will guide the design of the Paul trap which will be used for the measurement.

A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been installed and integrated into the TITAN experiment at TRIUMF. The MR-TOF-MS extends the capabilities and improves the performance of the TITAN experiment, for instance it provides fast isobar separation, short measurement cycles, yield measurements and broad-band beam diagnosis, and enhanced rate capabilities and dynamic range. Thereby, even more exotic nuclides become accessible at TITAN for experiments. Such improved capabilities of TITAN have been used in first experiments to investigate the sub-shell closure of neutron-rich nuclides at N = 32 and the r-process nucleo-synthesis for masses at A ∼ 85. The vacuum system, electronics and data-acquisition hardware and software have been recently upgraded. For the first time an isomeric state has been measured with TITAN′s MR-TOF-MS, 84mRb (excitation energy: 464 keV). The accurate measurement of excitation energies of low-lying isomeric states is possible due to the high mass resolving power of TITAN′s MR-TOF-MS and a specialized data-analysis procedure.