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The magnetism of Al$_x$Fe$_{2-x}$GeO$_5$ from $x$ = 0.09 to $x$ = 0.91 with andalusite structure was examined. The magnetic properties of Al$_x$Fe$_{2-x}$GeO$_5$ at low temperatures were found to be weak ferromagnetic-like state for $x$ $$ 0.3. The small spontaneous magnetization that appears in the weak ferromagnetic-like phase would be due to the presence of Dzyaloshinsky-Moriya interaction or to the difference in the magnitude of the magnetic moment of Fe$^{3+}$ in the octahedral and trigonal bipyramidal sites. The appearance of the spin-glass phase indicates that the dilution of Fe ions by Al ions in Al$_x$Fe$_{2-x}$GeO$_5$ causes the competition between ferromagnetic and antiferromagnetic interactions. The $x$ dependence of the site occupancy of Fe ions suggests that Fe$_2$GeO$_5$ with andalusite structure cannot be synthesized., Comment: 19 pages, 14 figure

We propose a method to measure the electron electric dipole moment (eEDM) using ultracold entangled francium (Fr) atoms trapped in an optical lattice, yielding an uncertainty below the standard quantum limit. Among the alkali atoms, Fr offers the largest enhancement factor to the eEDM. With a Fr based experiment, quantum sensing using quantum entangled states could enable a search for the eEDM at a level below 10−30 ecm. We estimate statistical and systematic errors attached to the proposed measurement scheme based on this quantum sensing technique. A successful quantum sensing of the eEDM could enable the exploration of new physics beyond the standard model of particle physics.

The scattering of Rb atoms on an anti-relaxation coating was studied. No significant change in the spin relaxation probability of Rb atoms by single scattering from a tetracontane surface was observed by cooling the film from 305 to 123 K. The mean surface dwell time was estimated using a time-resolved method.Delay-time spectra, from which mean surface dwell times can be estimated, were measured at 305, 153, and 123 K, with a time window of $9.3\times 10^{-5}$ s. The increase in mean surface dwell time with cooling from 305 to 123 K was smaller than $4.4\times 10^{-6}$ s, which is significantly smaller than the value expected from the mean dwell time at room temperature measured using the Larmor frequency shift. These results can be explained by assuming a small number of scattering components, with a mean surface dwell time at least three orders of magnitude longer than the majority component.

We characterized a double torsion pendulum system, including measurements of the photon-spin-induced torque. Our experimental strategy was similar to that used in Beth's experiment, which was performed in 1936 to measure photon-spin-induced torque using forced oscillation caused by polarization modulation of light incident on a suspended object. Through simple passive isolation of the suspended object from external vibration noise, the achieved torque sensitivity was 2 x 10^{-17} N m in a measurement time of 10^4 s, which is close to the thermal noise limit and one order smaller than the minimum torque measured in Beth's experiment. The observed spin-induced torque exerted on the light-absorbing optics is consistent with the angular momentum transfer of hbar per photon., 13 pages, 6 figures. Major revision. Journal accepted manuscript

The scattering of Rb atoms on paraffin coatings was studied. The results showed that the increase of surface dwell time by cooling from 305 to 123 K is smaller than 2.3 × 10−6 s.

Background gas in a rubidium vapor cell coated with paraffin as an anti-spin-relaxation coating was investigated. The cell was opened in a vacuum chamber to release background gas that was analyzed with a quadrupole mass spectrometer. The background gas was mainly composed of hydrocarbons of C3 and higher, as well as hydrogen.

We have developed a torsion balance to detect the rotation of a cell containing spin-polarized gaseous atoms to study angular momentum transfer from gaseous atoms to solid. A cesium vapor cell was hung from a thin wire in a vacuum chamber, and irradiated from the bottom with circularly polarized light tuned to the $D_2$ transition to polarize cesium atoms in the cell. By varying the light helicity at the resonance frequency of the torsion balance, we induced forced rotational oscillation of the cell and detected radiation torque exerted on the cesium vapor cell through the cesium atoms inside. The torque was particularly large when both hyperfine levels of cesium atoms were optically pumped with application of a longitudinal magnetic field. Further detailed study will provide new insights into spin-transfer processes at the gas-solid interface., Comment: 11 pages, 4 figures; v2: 12 pages, 4 figures. Corrected for a typo in Fig.2(a) in the journal version. Figures 3 and 4 were revised from v1. Some comments and references were also added to v1

A new laser spectroscopic method named “OROCHI (Optical RI-atom Observation in Condensed Helium as Ion catcher)” has been developed for deriving the nuclear spins and electromagnetic moments of low-yield exotic nuclei. In this method, we observe atomic Zeeman and hyperfine structures using laser-radio-frequency/microwave double-resonance spectroscopy. In our previous works, double-resonance spectroscopy was performed successfully with laser-sputtered stable atoms including non-alkali Au atoms as well as alkali Rb and Cs atoms. Following these works, measurements with 84−87Rb energetic ion beams were carried out in the RIKEN projectile fragment separator (RIPS). In this paper, we report the present status of OROCHI and discuss its feasibility, especially for low-yield nuclei such as unstable Au isotopes.

We performed scattering experiments using a rubidium (Rb) atomic beam on paraffin films and measured the angular and velocity distributions of scattered atoms. The paraffin films were prepared in various ways and characterized by atomic force microscopy and X-ray diffraction. The films exhibited various roughnesses and crystal structures. The paraffin films preserved the spin polarization of the scattered atoms. The measured angular distributions of all prepared films were consistent with Knudsen's cosine law. The velocity distributions were well fitted by Maxwell's distribution, characterized by a temperature much closer to the film temperature than to the atomic-beam temperature. We therefore concluded that the Rb atoms were well thermalized with the paraffin films via single scattering events., 18 pages, 10 figures, to be submitted to Physical Review A

We present an experimental technique to measure light shifts due to the nuclear spin independent (NSI) parity-nonconserving (PNC) interaction in the \( 7{S}_{1/2} \)–\( 6{D}_{3/2} \) transition in ultracold \( {}^{210}\mathrm{Fr} \) atoms. The approach we propose is similar to the one by Fortson (Phys Rev Lett 70:2383, 10) to measure the PNC-induced light shift which arises from the interference of parity nonconserving electric dipole transition and electric quadrupole transition amplitudes. Its major advantage is that it can treat more than \( {10}^4 \) ultracold \( {}^{210}\mathrm{Fr} \) atoms to enhance the shot noise limit. A relativistic coupled-cluster method has been employed to calculate the electric dipole transition amplitudes arising from the PNC interaction. Based on these calculations, we have evaluated the PNC-induced light shifts for transitions between the hyperfine levels of the \( 7{S}_{1/2} \) and \( 6{D}_{3/2} \) states and suitable transitions are identified for carrying out PNC measurements. It is possible in principle to probe new physics beyond the standard model with our proposed experimental scheme.

We have been developing a new nuclear laser spectroscopy method named “OROCHI” (Optical RI-atom Observation in Condensed Helium as Ion-catcher). OROCHI utilizes superfluid helium (He II) not only as an efficient stopping medium of highly energetic ions but also as a host matrix of in-situ atomic laser spectroscopy. Using these characteristic of He II, we produce atomic spin polarization and measure Zeeman and hyperfine structure (HFS) splitting using laser-RF (radio frequency) / MW (microwave) double resonance method. From the measured energy splittings, we can deduce nuclear spins and moments. So far, we have conducted a series of experiments using both stable (85,87Rb, 133Cs, 197Au, 107,109Ag) and unstable isotopes (84,86Rb) to confirm the feasibility of OROCHI method, especially observing Zeeman resonance and determining nuclear spins. The measurement of HFS splitting of atoms introduced into He II is indispensable to clarify the nuclear properties by deducing nuclear moments as well as the study of nuclear spins. For this purpose, we perform a precision measurement of HFS of 133Cs atoms immersed in He II using laser ablation technique. In this paper, we describe the result of the experiment.

Characteristics of a diffusion-bonded sapphire cell for optical experiments with hot metal vapors were investigated. The sapphire cell consisted of sapphire-crystal plates and a borosilicate-glass tube, which were bonded to each other by diffusion bonding without any binders or glues. The glass tube was attached to a vacuum manifold using the standard method applied in glass processing, filled with a small amount of Rb metal by chasing with a torch, and then sealed. The cell was baked at high temperatures and optical experiments were then performed using rubidium atoms at room temperature. The sapphire cell was found to be vacuum tight, at least up to 350$^{\circ}$C, and the sapphire walls remained clear over all temperatures. From the optical experiments, the generation of a background gas was indicated after baking at 200$^{\circ}$C. The background gas pressure was low enough to avoid pressure broadening of absorption lines but high enough to cause velocity-changing collisions of Rb atoms. The generated gas pressure decreased at higher temperatures, probably due to chemical reactions., 5 pages, 4 figures, \copyright 2017 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited

We present an experimental technique to measure light shifts due to the nuclear spin independent (NSI) parity-nonconserving (PNC) interaction in the $$7S_{1/2}$$ – $$6D_{3/2}$$ transition in ultracold $${^{210}\mathrm{Fr}}$$ atoms. The approach we propose is similar to the one by Fortson (Phys Rev Lett 70:2383, 10) to measure the PNC-induced light shift which arises from the interference of parity nonconserving electric dipole transition and electric quadrupole transition amplitudes. Its major advantage is that it can treat more than $$10^4$$ ultracold $${^{210}\mathrm{Fr}}$$ atoms to enhance the shot noise limit. A relativistic coupled-cluster method has been employed to calculate the electric dipole transition amplitudes arising from the PNC interaction. Based on these calculations, we have evaluated the PNC-induced light shifts for transitions between the hyperfine levels of the $$7S_{1/2}$$ and $$6D_{3/2}$$ states and suitable transitions are identified for carrying out PNC measurements. It is possible in principle to probe new physics beyond the standard model with our proposed experimental scheme.

A TRIAC (TRIode for Alternating Current switch) dimmable LED (Light Emitting Diode) driver based on the single-stage topology using a capacitor input rectifier provides many advantages such as small-scale implementation and low output current ripple. This circuit topology, however, has a problem: a large inrush current to the smoothing capacitor. To reduce the inrush current, this paper focuses on the bleeder circuit in the LED driver. This paper analyzes the relationship between the inrush current and the bleeder circuit operation and proposes a new bleeder circuit for reducing the inrush current. Experimental results demonstrate advantages of the proposed method, including inrush current reduction. The proposed method achieves further small-scale implementation and low electromagnetic noise for the intended circuit topology.

We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multilayered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers is assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz., Comment: 5 pages, 8 figures

We are developing a new nuclear laser spectroscopic technique for the study of nuclear structure that can be applied to short-lived low-yield atoms with unstable nuclei. The method utilizes superfluid helium (He II) as a trapping medium for high-energy ion beams. A liquid helium cryostat with optical windows is a key apparatus for this type of experiment. We describe the design and the performance of the cryostat which is developed for the present project.

A factory of laser-cooled francium (Fr) atoms is being developed to search for the electric dipole moment (EDM) of the electron. The factory has achieved the production of Fr ions of 9 × 10 5 particles/s and transport with a transmission efficiency of 2%. In pilot experiments, the magneto-optical trapping of rubidium (Rb) has been performed using a new ion-to-atom converter. To achieve the Fr trap, the development and design of each of the factory’s components are in progress.

We have been developing a novel nuclear laser spectroscopy method “OROCHI” for determining spins and moments of exotic radioisotopes. In this method, we use superfluid helium as a stopping material of energetic radioisotope beams and then stopped radioisotope atoms are subjected to in situ laser spectroscopy in superfluid helium. To confirm the feasibility of this method for rare radioisotopes, we carried out a test experiment using a 85 Rb beam. In this experiment, we have successfully measured the Zeeman resonance signals from the 85 Rb atoms stopped in superfluid helium by laser-RF double resonance spectroscopy. This method is efficient for the measurement of spins and moments of more exotic nuclei.

In order to investigate the structure of exotic nuclei with extremely low yields by measuring nuclear spins and moments, a new laser spectroscopy technique – “OROCHI” (Optical Radioisotopes Observation in Condensed Helium as Ion-catcher) has been proposed in recent years. The feasibility of this technique has been demonstrated by means of a considerable amount of offline and online studies of various atoms in superfluid helium. For in-situ laser spectroscopy of atoms in He II, trapping atoms in the observation region of laser is a key step. Therefore, a method which enables us to trap accelerated atoms at a precise position in He II is highly needed for performing experiment. In this work, a technique making use of a degrader, two plastic scintillators and a photon detection system is established for checking the stopping position of beam based on the LISE++ calculation. The method has been tested and verified by on-line experiments with the 84 , 85 , 87 Rb beam. Details of the experimental setup, working procedure and testing results of this method are presented.

The existence of a non-zero electric dipole moment (EDM) implies the violation of time reversal symmetry. As the time-reversal symmetry violation predicted by the Standard Model (SM) for the electron EDM is too small to be observed with current experimental techniques and any a non-zero EDM would indicate new physics beyond the SM. The tiny signal from the electron EDM is enhanced in the heavy atoms such as francium (Fr). We are constructing the laser-cooled Fr factory to search for the electron EDM.

We analyzed the surfaces of vitreous silica (quartz) and borosilicate glass (Pyrex) substrates exposed to rubidium (Rb) vapor by X-ray photoelectron spectroscopy (XPS) to understand the surface conditions of alkali metal vapor cells. XPS spectra indicated that Rb atoms adopted different bonding states in quartz and Pyrex. Furthermore, Rb atoms in quartz remained in the near-surface region, while they diffused into the bulk in Pyrex. For these characterized surfaces, we measured light-induced atom desorption (LIAD) of Rb atoms. Clear differences in time evolution, photon energy dependence, and substrate temperature dependence were found; the decay of LIAD by continuous ultraviolet irradiation for quartz was faster than that for Pyrex, a monotonic increase in LIAD with increasing photon energy from 1.8 to 4.3 eV was more prominent for quartz, and LIAD from quartz was more efficient at higher temperatures in the range from 300 to 580 K, while that from Pyrex was almost independent of temperature.

We measured the rate of velocity-changing collisions (VCCs) between alkali atoms and background gas in buffer-gas-free anti-relaxation-coated cells. The average VCC rate in paraffin-coated rubidium vapor cells prepared in this work was $1 \times 10^{6}$ s$^{-1}$, which corresponds to $\sim 1$ mm in the mean free path of rubidium atoms. This short mean free path indicates that the background gas is not negligible in the sense that alkali atoms do not travel freely between the cell walls. In addition, we found that a heating process known as "ripening" increases the VCC rate, and also confirmed that ripening improves the anti-relaxation performance of the coatings., Comment: 5 pages, 4 figures

Plant roots play important roles not only in the absorption of water and nutrients, but also in stress tolerance. Previously, we identified RSOsPR10 as a root-specific pathogenesis-related (PR) protein induced by drought and salt treatments in rice. Transcripts and proteins of RSOsPR10 were strongly induced by jasmonate (JA) and the ethylene (ET) precursor 1-aminocyclopropane-1-carboxylic acid (ACC), while salicylic acid (SA) almost completely suppressed these inductions. Immunohistochemical analyses showed that RSOsPR10 strongly accumulated in cortex cells surrounding the vascular system of roots, and this accumulation was also suppressed when SA was applied simultaneously with stress or hormone treatments. In the JA-deficient mutant hebiba, RSOsPR10 expression was up-regulated by NaCl, wounding, drought and exogenous application of JA. This suggested the involvement of a signal transduction pathway that integrates JA and ET signals in plant defense responses. Expression of OsERF1, a transcription factor in the JA/ET pathway, was induced earlier than that of RSOsPR10 after salt, JA and ACC treatments. Simultaneous SA treatment strongly inhibited the induction of RSOsPR10 expression and, to a lesser extent, induction of OsERF1 expression. These results suggest that JA/ET and SA pathways function in the stress-responsive induction of RSOsPR10, and that OsERF1 may be one of the transcriptional factors in the JA/ET pathway.

We have been developing a new nuclear laser spectroscopic method “OROCHI” for determining spins and moments of exotic RIs. It is the method based on the combination of superfluid helium as a stopper of radioactive isotope (RI) beam and in situ laser spectroscopy of RI atoms. This unique method will enable us to measure nuclear spins and electromagnetic moments of extremely low yield RI (less than 1 particle per second). For applying this method to stable Ag and Au isotopes, we have measured optical absorption spectra of these elements. Optical pumping of those atoms has also been attempted with pumping lasers tuned to the measured absorption lines. Details of this laser spectroscopy method in He II “OROCHI” and the development for applying OROCHI to Ag and Au atoms are presented.

We have been developing a new laser spectroscopic technique “OROCHI,” which is based on the combination of superfluid helium as a stopper of radioactive isotope (RI) beam and in-situ laser spectroscopy of RI atoms, for determining spins and moments of exotic RIs. By using this unique technique, it is feasible to measure nuclear spins and electromagnetic moments of extremely low yield RI (estimated as less than 1 pps). Recently, we have demonstrated that nuclear spins and moments are obtained from Zeeman and hyperfine splittings of stable Rb isotopes measured using this OROCHI technique. Details of this laser spectroscopy method in He II “OROCHI” and the summary of our development are presented.

Rang Dong basement reservoir is a granitic naturally fractured reservoir. Unlike carbonate fractured system, basement matrix porosity is negligible. The storage and production are dominated by the fracture system. After primary depletion, water injection was commenced to further improve the oil recovery and production of the reservoir. Water injection in fractured reservoir is particularly challenging as it is very much dependant on the fracture connectivity, geometry and orientation. To manage the water injection strategy of the basement reservoir, a thorough understanding of the fluid flow is crucial. Therefore, radioactive tracer injection/monitoring were employed in different part of the field to obtain information on fluid path.Tracer injection/monitoring have been established as a proven and efficient technology to obtain information on well-to-well communication, heterogeneities and fluid dynamics. However, interpretation may in some cases not straight forward, therefore integration with other types of reservoir and production data are important to get a consistent and accurate interpretation.This paper demonstrates an integrated approach where it combined tracer injection/monitoring with other surveillance application for well planning and reservoir management. One of the surveillance is the monitoring of the water chemical composition through regular sampling and analysis of produced water. This method serves as the tracking of movement of formation/aquifer water and injected seawater. Another analysis involves the monitoring of produced water isotopes. Oil finger printing is also used as another source of information to be combined into the overall interpretation. Oil finger printing is used to identify any reservoir compartmentalization, reservoir extent and connectivity. Other reservoir data and applications used are well production performance, well pressure transient analyses, material balance analyses and etc.This paper documents some actual examples where the tracer injection/monitoring analyses integrated with all available information were used to derive at actual well planning or reservoir management strategy that was eventually applied in the field.

Resonance transitions between the Zeeman sublevels of optically-polarized Rb atoms traveling through a spatially periodic magnetic field are investigated in a radio-frequency (rf) range of sub-MHz. The atomic motion induces the resonance when the Zeeman splitting is equal to the frequency at which the moving atoms feel the magnetic field oscillating. Additional temporal oscillation of the spatially periodic field splits a motion-induced resonance peak into two by an amount of this oscillation frequency. At higher oscillation frequencies, it is more suitable to consider that the resonance is mainly driven by the temporal field oscillation, with its velocity-dependence or Doppler shift caused by the atomic motion through the periodic field. A theoretical description of motion-induced resonance is also given, with emphasis on the translational energy change associated with the internal transition., Comment: 7 pages, 3 figures, final version

We observed resonant coherent excitation (RCE) of 1s electron to the n = 2 states in 390 MeV/u Ar 17+ ions passing through thin Si crystals of about 1 μm in the {2 2 0} planar-channeling condition by measuring both the exit charge state and the exit angle of the emerged ions simultaneously in a list mode. The yield of the de-excitation X-rays from the Ar 17+ ions was also measured. The thin crystal is suitable to study trajectory dependent RCE dynamics, because the exit angle of the high energy planar-channeling ion is uniquely related to the ion trajectory. From the de-excitation X-ray yield on resonance, we learned that RCE occurs with a fairly large probability within the traveling length of about 1 μm, and a majority of the excited ions survive from ionization by the collisions with target electrons or nuclei, and de-excite into the ground state by emitting the X-rays. On the other hand, the observed resonance profile of the exit charge state is shallow and broadened by the Stark effect. We found that the ionization of the excited ions takes place when the ions travel close to the atomic plane from the observed relation between the charge state and the exit angle of the emerged ions.

We investigated resonant coherent excitation of H-like Ar17+ and He-like Ar16+ ions planar channeled in a Si crystal under the V-type and ladder-type double resonance conditions. In both cases, we observed distinct enhancement in the ionized fraction of the transmitted ions when the double resonance conditions were satis.ed. In the ladder-type configuration, the enhancement indicates that the doubly-excited 2p2 state of He-like Ar16+was produced through doubly-resonant coherent excitation.

In this paper, we report on a laser spectroscopy measurement of ${}^{84\ensuremath{-}87}\mathrm{Rb}$ isotopes in superfluid helium (He ii) at 1.8 K using laser--radio-frequency double-resonance spectroscopy. Rb ion beams $(g60$ MeV/u) provided by the RIKEN projectile fragment separator (RIPS) were injected and trapped into He ii. The stopping position of atoms in He ii was precisely confirmed by laser spectroscopy. By optically pumping the trapped Rb isotopes, large atomic spin polarization (up to 40%) of each observed isotope in the ground state was achieved. The laser--radio-frequency double-resonance spectra were observed for stable ${}^{85,87}\mathrm{Rb}$ isotopes as well as for unstable isotopes ${}^{84,84m,86}\mathrm{Rb}$ by scanning a weak magnetic field with a fixed-frequency RF field. From the measured Zeeman splitting, nuclear spin values for ${}^{84m,84\ensuremath{-}87}\mathrm{Rb}$ isotopes were determined with reasonable accuracy. The number of ions injected into He ii for the resonance spectra measurement was on the order of $10{}^{4}$ particles per second. This work may open new opportunities for the study of various particles trapped in condensed helium in several fields.

Multiple ionization processes of argon atoms by a linearly polarized laser light with the maximum peak intensity of about 5 × 1015 W cm−2 were investigated by the recoil-ion momentum spectroscopy. Momentum distributions of argon ions with charge states 3+ and 4+ were measured. The experimental results were compared with calculations based on the sequential ionization model and the ADK ionization rate [M.V. Ammosov et al., Zh. Eksp. Teor. Fiz. 91 (1986) 2008 (Sov. Phys. JETP 64 (1986) 1191)]. The calculated widths of the distributions agreed with the experimental results to within 30%.

The excited states in the light neutron-rich nucleus 11Be have been studied through the β-delayed neutron- and γ-decays from spin-polarized 11Lig.s.. The level scheme and decay scheme of 11Be∗ are established from the β–γ, β–n and β–n–γ coincidences, and the spins and parities for 7 levels in 11Be are firmly assigned from the β-decay asymmetries measured in coincidence with the delayed radiations. The neutron-spectroscopic factors of the levels in 11Be are also determined. Some of the levels show good accord with predictions by the anti-symmetrized molecular dynamics (AMD) theory, which predicts various types of 2α-cluster states in the rotational bands and a single α-cluster state.