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Journal Articles

Study of charged particle activation analysis, 2; Determination of boron concentration in human blood samples

Ikebe, Yurie*; Oshima, Masumi*; Bamba, Shigeru*; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi*; Bi, C.*; Seto, Hirofumi*; Amano, Hikaru*; et al.

Applied Radiation and Isotopes, 164, p.109106_1 - 109106_7, 2020/10

Boron Neutron Capture Therapy (BNCT) is a radiotherapy for the treatment of intractable cancer. In BNCT precise determination of $$^{10}$$B concentration in whole blood sample before neutron irradiation is crucial for control of the neutron irradiation time and the neutron dosimetry. We have applied the Charged Particle Activation Analysis (CPAA) to non-destructive and accurate determination of $$^{10}$$B concentration in whole blood sample. The experiment was performed at JAEA Tandem Accelerator using an 8 MeV proton beam. The 478 keV $$gamma$$ ray of $$^{7}$$Be produced in the $$^{10}$$B(p,$$alpha$$)$$^{7}$$Be reaction was used to quantify the $$^{10}$$B, and $$gamma$$ rays of $$^{56}$$Co originating from the reaction with Fe in blood was used to normalize the $$gamma$$-ray intensity. The results demonstrated that the present CPAA method can be applied to the determination of the $$^{10}$$B concentration in the blood sample.

Journal Articles

Origin of the dramatic change of fission mode in fermium isotope investigated using Langevin equations

Aritomo, Yoshihiro*; Miyamoto, Yuya*; Nishio, Katsuhisa

Nippon Butsuri Gakkai-Shi, 75(10), p.631 - 636, 2020/10

no abstracts in English

Journal Articles

Actinides and transactinides

Nagame, Yuichiro*; Sato, Tetsuya; Kratz, J. V.*

Kirk-Othmer Encyclopedia of Chemical Technology (Internet), 52 Pages, 2020/09

This article gives a brief summary of the recent progress in the synthesis of new elements as well as heavy nuclei far from the stability line and in the studies of exotic nuclear decay properties including nuclear fission of heavy nuclei and chemical characterization of heavy actinides and transactinides. Experimental techniques of single-atom detection after in-flight separation with electromagnetic separators have made a breakthrough in discovery of new heavy isotopes. Development of automated rapid chemical separation apparatuses performing one atom-at-a-time chemistry has also considerably contributed to the progress of chemical studies of the transactinides. Some key experiments exploring new frontiers of the production and chemical characterization of heavy actinides and transactinides using state-of-the-art techniques are demonstrated. A short historical perspective of actinide and transactinide elements and some prospects of extending nuclear and chemical studies of heavy elements in the future are briefly presented.

Journal Articles

Analysis of ion-irradiation induced lattice expansion and ferromagnetic state in CeO$$_{2}$$ by using Poisson distribution function

Yamamoto, Yuki*; Ishikawa, Norito; Hori, Fuminobu*; Iwase, Akihiro*

Quantum Beam Science (Internet), 4(3), p.26_1 - 26_13, 2020/09

The lattice constant and the magnetic state of CeO$$_{2}$$ are modified by the irradiation with 200 MeV Xe ions. Under the assumption that these modifications are induced in the narrow one-dimensional region (the ion track) along the ion beam path, the dependence of the lattice constant and the saturation magnetization of CeO$$_{2}$$ on the Xe ion fluence can be analyzed by using the Poisson distribution function. The analysis reveals that the lattice constant inside the ion track, which is larger than outside the ion track is not affected by the overlapping of the ion track. The present result implies that the Poisson distribution function is useful for describing the effect of ion track overlapping on the ion irradiation induced ferromagnetic state in CeO$$_{2}$$.

JAEA Reports

Development of new corona probe

Nakamura, Masahiko; Kutsukake, Kenichi; Matsuda, Makoto

JAEA-Technology 2019-022, 20 Pages, 2020/03

JAEA-Technology-2019-022.pdf:1.73MB

The JAEA Tokai tandem accelerator (an electrostatic accelerator) has the advantage that it can accelerate an ion beam with proportional energy to its acceleration voltage. Therefore the control of an ion beam energy can be automated when the control of the acceleration voltage can be automated by using the scaling operation system: an electromagnetics proportion of optical device parameters, and the ganged control system: a synchronized controlling related devices in the JAEA Tokai Tandem accelerator control system. We should improve several devices to achieve the automatic control of the accelerator voltage. Especially, the positioning system of the corona probe which adjusts the acceleration voltage had to be automated. However the original corona probe was difficult to be applied to the automation by its poor control system and low positioning precision. We have developed the new corona probe which improved defects of the original one. The new corona probe has an automatic and high precision positioning system and enhanced maintainability by new control system, new driven system and new position detection system. We describe about the development of the new corona probe in detail.

Journal Articles

TEM analysis of ion-tracks and hillocks produced by swift heavy ions of different velocities in Y$$_{3}$$Fe$$_{5}$$O$$_{12}$$

Ishikawa, Norito; Taguchi, Tomitsugu*; Kitamura, Akane; Szenes, G.*; Toimil-Molares, M. E.*; Trautmann, C.*

Journal of Applied Physics, 127(5), p.055902_1 - 055902_7, 2020/02

 Times Cited Count:1 Percentile:28.87(Physics, Applied)

Hillock formation is one of the important aspects of radiation-induced modification of solid material. To our knowledge this is first result showing that the hillock formation in ceramics is affected by the velocity effect. The present result include Se-dependences of hillock dimensions based on precise measurement using TEM (transmission electron microscopy). The paper should be published to make researchers aware that hillock size is actually comparable to ion-track size in wide Se range. In addition, the results include important insight about the hillock formation mechanism of ceramics irradiated with swift heavy ions.

Journal Articles

Study of quasielastic barrier distributions as a step towards the synthesis of superheavy elements with hot fusion reactions

Tanaka, Taiki*; Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Boll, R. A.*; Brewer, N. T.*; Van Cleve, S.*; Dean, D. J.*; Ishizawa, Satoshi*; et al.

Physical Review Letters, 124(5), p.052502_1 - 052502_6, 2020/02

 Times Cited Count:1 Percentile:100(Physics, Multidisciplinary)

Journal Articles

New excited 2$$^+$$ and 3$$^-$$ two-proton states in $$_{84}^{210}$$Po$$_{126}$$ populated by two-proton transfer

Dupont, E.*; Astier, A.*; Petrache, C. M.*; Lv, B. F.*; Deloncle, I.*; Kiener, J.*; Orlandi, R.; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; et al.

Physical Review C, 101(1), p.014309_1 - 014309_6, 2020/01

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

Journal Articles

FE-SEM observation of chains of nanohillocks in SrTiO$$_{3}$$ and Nb-doped SrTiO$$_{3}$$ surfaces irradiated with swift heavy ions

Kitamura, Akane; Ishikawa, Norito; Kondo, Keietsu; Yamamoto, Shunya*; Yamaki, Tetsuya*

Nuclear Instruments and Methods in Physics Research B, 460, p.175 - 179, 2019/12

 Times Cited Count:0 Percentile:100(Instruments & Instrumentation)

Irradiation at grazing incidence formed chains of multiple hillocks on the surface of strontium titanate (SrTiO$$_{3}$$) and titanium oxide (TiO$$_{2}$$). They were observed with an atomic force microscope (AFM), however, the AFM measurement gives resolution errors in a nanometer order due to the curvature of the probe tip. To prevent these errors, a field emission scanning electron microscope (FE-SEM) would be a better option for observation. In this study, we performed SEM observations for the chains of the multiple hillocks. Single crystals of SrTiO$$_{3}$$ and TiO$$_{2}$$ were irradiated with 200 MeV $$^{136}$$Xe$$^{14+}$$ in the tandem accelerator at JAEA-Tokai. It was revealed that a lot of isolated hillocks were formed in a line on these surface. The diameter and the interval of those hillocks are discussed in comparison to AFM observation.

Journal Articles

Effects of multichance fission on isotope dependence of fission fragment mass distributions at high energies

Tanaka, Shoya; Aritomo, Yoshihiro*; Miyamoto, Yuya*; Hirose, Kentaro; Nishio, Katsuhisa

Physical Review C, 100(6), p.064605_1 - 064605_6, 2019/12

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

Fission fragment mass distributions of $$^{234-240}$$U, $$^{236-242}$$Np, and $$^{238-244}$$Pu are studied using the Langevin approach in the widely excitation energy range as $$E^{*}$$ = 15-55 MeV. In the present calculation, neutron emission before fission, so called multichance fission, was introduced. The calculated results well demonstrated the experimental data, which shows the double-peak structure up to the highest excitation energies and the clear dependence on the initial fissioning nuclides. The trend is nicely correlated with the neutron binding energy of the compound nucleus that dominates the neutron emission probability before fission.

Journal Articles

First ionization potentials of Fm, Md, No and Lr; Verification of filling-up of 5f electrons and confirmation of the actinide series

Sato, Tetsuya

Kagaku To Kogyo, 72(10), P. 867, 2019/10

We conducted measurements of the first ionization potential (IP$$_1$$) of the heavy actinide elements, lawrencium (Lr, $$Z = 103$$), nobelium (No, $$Z = 102$$), mendelevium (Md, $$Z = 101$$) and fermium (Fm, $$Z = 100$$) by using a novel method based on a surface ionization process. The IP$$_1$$ measurements have been performed using the ISOL (Isotope Separator On-Line) system equipped with a surface ion-source with short-lived heavy actinide isotopes, $$^{256}$$Lr ($$T_{1/2}$$ = 27s), $$^{257}$$No ($$T_{1/2}$$ = 24.5s), $$^{251}$$Md ($$T_{1/2}$$ = 4.27 min), and $$^{249}$$Fm ($$T_{1/2}$$ = 2.6 min). Our experimental results clearly showed that the IP$$_1$$ of Lr is distinctly low among actinide elements. Moreover, No has the highest IP$$_1$$ among them due to its full-filled 5f and 7s orbitals; the IP$$_1$$ value increased with an atomic number up to No and decreased dramatically at Lr, indicating the similar trend with that of heavy lanthanide elements. Therefore, we concluded Lr would be the last member of the actinide series.

Journal Articles

Effects of the nuclear structure of fission fragments on the high-energy prompt fission $$gamma$$-ray spectrum in $$^{235}$$U($$n_{rm th},f$$)

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; L$'e$guillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; K$"o$ster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.

Physical Review C, 100(4), p.044610_1 - 044610_7, 2019/10

 Times Cited Count:1 Percentile:60.45(Physics, Nuclear)

Journal Articles

Sensitivity of charged particle activation analysis for long-lived radioactive nuclide determination

Oshima, Masumi*; Yamaguchi, Yurie*; Asai, Masato; Tsukada, Kazuaki; Goto, Jun*; Bamba, Shigeru*; Bi, C.*; Morimoto, Takao*

Journal of Nuclear Science and Technology, 56(9-10), p.866 - 872, 2019/09

 Times Cited Count:1 Percentile:56.06(Nuclear Science & Technology)

Sensitivity of charged particle activation analysis with 8 MeV proton beam was studied for determination of 35 long-lived radioactive nuclides. Reaction cross sections for those nuclides were estimated with ALICE-91 code and isomer yield ratios were estimated from those of neighboring isotopes by taking into account their spins and parities. It was found that the proposed charged particle activation analysis should show high sensitivity for the determination of several hardly measurable nuclides with long half-lives such as $$^{135}$$Cs, $$^{244}$$Pu, $$^{129}$$I, $$^{126}$$Sn, $$^{93}$$Mo, $$^{107}$$Pd, $$^{236}$$U, $$^{248}$$Cm, and $$^{237}$$Np.

Journal Articles

Validation of the multinucleon transfer method for the determination of the fission barrier height

Kean, K. R.; Nishio, Katsuhisa; Hirose, Kentaro; Vermeulen, M. J.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Andreyev, A. N.; Tsekhanovich, I.*; Chiba, Satoshi*

Physical Review C, 100(1), p.014611_1 - 014611_6, 2019/07

 Times Cited Count:0 Percentile:100(Physics, Nuclear)

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Matsuda, Makoto; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; et al.

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1270 - 1273, 2019/07

The JAEA-Tokai tandem accelerator was operated over a total of 138 days, and delivered 16 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2018. Maximum acceleration voltage was 16.6 MV. A new beam attenuator was installed at the entrance beam line of the tandem accelerator to facilitate control of the beam current and minimize stripper foil consumption. The main maintenance items included replacing the pellet chain used for about 68,000 hours and the drive motor for the high voltage terminal generator used for about 9 years. A fault has occurred in the building's oxygen deficiency monitor. This paper describes the operational status of the accelerators and the major technical developments of our facility.

Journal Articles

Optimization of an isothermal gas-chromatographic setup for the chemical exploration of dubnium (Db, Z = 105) oxychlorides

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Ito, Yuta; Shirai, Kaori*; Suzuki, Hayato; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; et al.

Journal of Radioanalytical and Nuclear Chemistry, 320(3), p.633 - 642, 2019/06

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

An isothermal gas-chromatographic (IGC) device has been developed and tested for on-line gas phase studies of volatile oxychlorides of short-lived group-5 transition metals. Radioisotopes of niobium and tantalum, produced in nuclear fusion evaporation reactions, are directly flushed into the IGC setup by an inert gas-jet. Oxychloride compounds are formed by the addition of SOCl$$_2$$ and O$$_2$$. Parameters influencing the formation and transport of NbOCl$$_3$$ and TaOCl$$_3$$ are investigated. For nuclides with half-lives ($$t_{1/2}$$) of about 30 s, an overall efficiency of 7% is obtained, rendering the IGC setup suitable for the chemical exploration of $$^{262}$$Db($$t_{1/2}$$ = 34s).

Journal Articles

FE-SEM observations of multiple nanohillocks on SrTiO$$_{3}$$ irradiated with swift heavy ions

Kitamura, Akane; Ishikawa, Norito; Kondo, Keietsu; Fujimura, Yuki; Yamamoto, Shunya*; Yamaki, Tetsuya*

Transactions of the Materials Research Society of Japan, 44(3), p.85 - 88, 2019/06

Swift heavy ions can create nanosized hillocks on the surfaces of various ceramics. When these materials are irradiated with swift heavy ions at normal incidence, each ion impact results in the formation of a single hillock on the surfaces. In contrast, irradiation at grazing incidence forms chains of multiple hillocks on the surface, for example, for strontium titanate (SrTiO$$_{3}$$). So far, chains of multiple hillocks have been investigated using atomic force microscopy (AFM). It should be noted that AFM measurements involve systematic errors of several nanometers due to the finite size of the probe tip. Consequently, it is possible that the image of one hillock may merge with that of a neighboring hillock even if the two hillocks are well separated. In contrast to AFM, field-emission scanning electron microscopy (FE-SEM) is a useful technique for obtaining higher-resolution images. In this study, we observed multiple nanohillocks on the surfaces of SrTiO$$_{3}$$ using FE-SEM. Crystals of SrTiO$$_{3}$$(100) and 0.05 wt% Nb-doped SrTiO$$_{3}$$(100) were irradiated with 350 MeV Xe ions, respectively, at grazing incidence, where the angle between the sample surface and the beam was less than 2$$^{circ}$$. On the SrTiO$$_{3}$$ surface, a chain of periodic nanohillocks is created along the ion path. In contrast, black lines accompanied by hillocks are observed on the Nb-doped SrTiO$$_{3}$$ surface.

Journal Articles

Origin of the dramatic change of fission mode in fermium isotopes investigated using Langevin equations

Miyamoto, Yuya*; Aritomo, Yoshihiro*; Tanaka, Shoya; Hirose, Kentaro; Nishio, Katsuhisa

Physical Review C, 99(5), p.051601_1 - 051601_7, 2019/05

 Times Cited Count:4 Percentile:16.29(Physics, Nuclear)

Journal Articles

Observation of the competing fission modes in $$^{178}$$Pt

Tsekhanovich, I.*; Andreyev, A. N.; Nishio, Katsuhisa; Denis-Petit, D.*; Hirose, Kentaro; Makii, Hiroyuki; Matheson, Z.*; Morimoto, Koji*; Morita, Kosuke*; Nazarewicz, W.*; et al.

Physics Letters B, 790, p.583 - 588, 2019/03

 Times Cited Count:8 Percentile:5.43(Astronomy & Astrophysics)

Journal Articles

Formation and thermochemical properties of oxychlorides of niobium (Nb) and tantalum (Ta); Towards the gas-phase investigation of dubnium (Db) oxychloride

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Suzuki, Hayato*; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; Nagame, Yuichiro

Inorganica Chimica Acta, 486, p.361 - 366, 2019/02

 Times Cited Count:1 Percentile:72.9(Chemistry, Inorganic & Nuclear)

The formation of NbOCl$$_3$$ and TaOCl$$_3$$ and their adsorption behavior on quartz surfaces was explored by applying an isothermal gas-chromatographic method. Trace amounts of short-lived Nb and Ta isotopes were used. Adsorption enthalpy values ($$Delta H_{rm ads}$$) at zero surface coverage of -$$Delta H_{rm ads}$$(NbOCl$$_3$$) = 102 $$pm$$ 4 kJ/mol and -$$Delta H_{rm ads}$$(TaOCl$$_3$$) = 128 $$pm$$ 5 kJ/mol were determined by analyzing the chromatographic behavior of the Nb andTa complexes with a Monte-Carlo simulation method based on an adsorption-desorption kinetic model.By applying an empirical correlation, the experimental $$Delta H_{rm ads}$$ values were successively related to the macroscopic standard sublimation enthalpy, $$Delta H^circ _{rm subl}$$, as a measure of the volatility of each substance. The inferred sublimation enthalpies are in agreement with tabulated thermochemical values. Thus, the linear empirical correlation between $$Delta H_{rm ads}$$ and $$Delta H^circ _{rm subl}$$ for metal-oxychlorides was updated with the inclusion of the present data. According to the predicted $$Delta H^circ _{rm subl}$$(DbOCl$$_3$$), a $$Delta H_{rm ads}$$(DbOCl$$_3$$) value of 135 $$pm$$ 2 kJ/mol was extrapolated. The future accomplishment of comparative studies with DbOCl$$_3$$ under the same experimental conditions will provide valuable information on the volatility trend in Group-5 elements, together with an indication on the magnitude of relativistic effects on the electronic structure of dubnium.

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