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Journal Articles

Structure analysis of asymmetric interface using spin-contrast-variation neutron reflectometry

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Hamon, 32(4), p.165 - 168, 2022/11

We demonstrated the advantage of spin-contrast-variation neutron reflectometry on the structure analysis of buried interface between resin and porous silica layers. The interface structure was not reproduced by the normal Gaussian model, but by the asymmetric interface model where crosslinked polymer chains neither permeate the pore nor follow the surface roughness of the silica layer.

Journal Articles

Structure analysis of a buried interface between organic and porous inorganic layers using spin-contrast-variation neutron reflectivity

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Journal of Applied Crystallography, 55(5), p.1147 - 1153, 2022/10

AA2021-0903.pdf:1.06MB

 Times Cited Count:2 Percentile:37.43(Chemistry, Multidisciplinary)

Spin-contrast-variation neutron reflectivity obtains multiple reflectivity curves from a single sample and a single beam source. We used the strong point of the technique to reveal that, although methylated-perhydropolysilazane-derived silica layer has a higher porosity near the interface with acrylic urethane resin, the resin did not permeate the pore network.

Journal Articles

Mechanisms responsible for adsorption of molybdate ions on alumina for the production of medical radioisotopes

Fujita, Yoshitaka; Niizeki, Tomotake*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; Yamauchi, Yusuke*; Malgras, V.*; Kaneti, Y. V.*; Liu, C.-H.*; Hatano, Kentaro*; Suematsu, Hisayuki*; et al.

Bulletin of the Chemical Society of Japan, 95(1), p.129 - 137, 2022/01

 Times Cited Count:9 Percentile:63.53(Chemistry, Multidisciplinary)

In this work, the mechanisms responsible for the adsorption of molybdate ions on alumina are investigated using in-depth surface analyses carried out on alumina specimens immersed in solutions containing different molybdate ions at different pH values. The obtained results reveal that when alumina is immersed in an acidic solution containing molybdate ions, the hydroxyl groups present on the surface are removed to generate positively charged sites, and molybdate ions (MoO$$_{4}$$$$^{2-}$$ or AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$, which is more easily desorbed than MoO$$_{4}$$$$^{2-}$$. Furthermore, the enhancement in the Mo adsorption or desorption property may be achieved by enriching the surface of the alumina adsorbent with many -OH groups and optimizing Mo solution to adsorb molybdate ions on alumina as MoO$$_{4}$$$$^{2-}$$ ions. These findings will assist researchers in engineering more efficient and stable alumina-based adsorbents for molybdenum adsorption used in medical radioisotope ($$^{99}$$Mo/$$^{99m}$$Tc) generators.

JAEA Reports

Preliminary test for Mo recycling system in $$^{99}$$Mo manufacturing process, 1; Reusability evaluation of Mo absorbent (Joint research)

Kimura, Akihiro; Niizeki, Tomotake*; Kakei, Sadanori*; Chakrova, Y.*; Nishikata, Kaori; Hasegawa, Yoshio*; Yoshinaga, Hideo*; Chakrov, P.*; Tsuchiya, Kunihiko

JAEA-Technology 2013-025, 40 Pages, 2013/10

JAEA-Technology-2013-025.pdf:2.62MB

Neutron Irradiation and Testing Reactor Center has developed the production of a medical isotope of $$^{99}$$Mo, the parent nuclide of $$^{99m}$$Tc by the (n,$$gamma$$) method using JMTR. The (n,$$gamma$$) method has an advantage of easy manufacturing process and low radioactive wastes generation. However, the low radioactivity concentration of $$^{99m}$$Tc is remaining as an issue. Therefore, PZC and PTC have been developed as adsorbent of molybdenum. Meanwhile, it is necessary to recycle the absorbent and Mo for the reduction of the radioactive waste of used-adsorbent and the effective use of limited resources, respectively. This report summarizes results of the synthesis of Mo adsorbents such as PZC and PTC, and the performance tests.

Journal Articles

Mo recycling property from generator materials with irradiated molybdenum

Kakei, Sadanori*; Kimura, Akihiro; Niizeki, Tomotake*; Ishida, Takuya; Nishikata, Kaori; Kurosawa, Makoto; Yoshinaga, Hideo*; Hasegawa, Yoshio*; Tsuchiya, Kunihiko

Proceedings of 6th International Symposium on Material Testing Reactors (ISMTR-6) (Internet), 7 Pages, 2013/10

The Japan Materials Testing Reactor (JMTR) is expected to contribute to the expansion of industrial utilization, such as the domestic production of $$^{99}$$Mo for the medical diagnosis medicine $$^{rm 99m}$$Tc. Production by the (n, $$gamma$$) method is proposed as domestic $$^{99}$$Mo production in JMTR because of the low amount of radioactive wastes and the easy $$^{99}$$Mo/$$^{rm 99m}$$Tc production process. Molybdenum oxide (MoO$$_{3}$$) pellets, poly zirconium compounds (PZC) and poly titanium compounds (PTC) are used as the irradiation target and generator for the production of $$^{99}$$Mo/$$^{rm 99m}$$Tc by the (n, $$gamma$$) method. However, it is necessary to use the enriched $$^{98}$$MoO$$_{3}$$, which is very expensive, to increase the specific activity of $$^{99}$$Mo. Additionally, a large amount of used PZC and PTC is generated after the decay of $$^{99}$$Mo. Therefore, this recycling technology of used PZC/PTC has been developed to recover molybdenum (Mo) as an effective use of resources and a reduction of radioactive wastes. The total Mo recovery rate of this process was 95.8%. From the results of the hot experiments, we could demonstrate that the recovery of MoO$$_{3}$$ and the recycling of PZC are possible. In the future, the equipment of recovering Mo will be installed in JMTR-Hot Cell, and this recycling process will be able to contribute to the reduction of production costs of $$^{rm 99m}$$Tc and the reduction of radioactive wastes.

Oral presentation

Syntheses of polytitanium compound without chlorine as molybdenum absorbent for $$^{99}$$Mo-$$^{99m}$$Tc generator

Niizeki, Tomotake*; Hishinuma, Yukio*; Suzuki, Masashi*; Hasegawa, Yoshio*; Nishikata, Kaori; Kimura, Akihiro; Ishida, Takuya; Tanimoto, Masataka; Tsuchiya, Kunihiko

no journal, , 

JP, 2010-263801   Patent publication (In Japanese)

no abstracts in English

Oral presentation

Fabrication technique development of high-density MoO $$_{3}$$ pellets for $$^{99}$$Mo/ $$^{99m}$$Tc production

Nishikata, Kaori; Kimura, Akihiro; Kato, Yoshiaki; Kurosawa, Makoto; Ishida, Takuya; Tsuchiya, Kunihiko; Kakei, Sadanori*; Yoshinaga, Hideo*; Niizeki, Tomotake*; Hasegawa, Yoshio*

no journal, , 

no abstracts in English

Oral presentation

Effect on sintering property of MoO$$_{3}$$ pellets from different MoO$$_{3}$$ powders

Nishikata, Kaori; Kimura, Akihiro; Kakei, Sadanori*; Niizeki, Tomotake*; Ishida, Takuya; Yoshinaga, Hideo*; Hasegawa, Yoshio*; Tsuchiya, Kunihiko

no journal, , 

Every year in Japan, nuclear medical of about 900,000 cases are carried out using technetiume-99m ($$^{99m}$$Tc). It is ranked as the second in the world. But all of the $$^{99m}$$Tc is imported from the other countries. Therefore, we are developing the (n, $$gamma$$) method for $$^{99}$$Mo production, as part of "increase of industrial use" in resumed operations after restart of Japan Materials Tasting Reactor (JMTR). In the study to establish the $$^{99}$$Mo production method through the (n, $$gamma$$) process domestically using the JMTR, three different MoO$$_{3}$$ powders such as fresh, recycled and $$^{98}$$Mo enriched ones were selected, and characterized as in SEM and sintering. As a result, the high dense MoO$$_{3}$$ pellet manufactured by the fresh powder attained over 90%T. D. at the sintering temperature of 500$$^{circ}$$C. On the other hand, pellets manufactured by the other powders needs sintering temperature above 580$$^{circ}$$C to attain over 90%T.D., resulting in an influence on the particle size and shape dependences for the sintering property.

Oral presentation

Research and development of $$^{99}$$Mo/$$^{99m}$$Tc production process by (n,$$gamma$$) reaction under Tsukuba International Strategic Zones

Tsuchiya, Kunihiko; Kawamata, Kazuo; Takeuchi, Nobuhiro*; Ishizaki, Hiroyuki*; Niizeki, Tomotake*; Kakei, Sadanori*; Fukumitsu, Nobuyoshi*; Araki, Masanori

no journal, , 

no abstracts in English

Oral presentation

Consideration of molybdenum adsorption behavior of alumina by surface analysis

Suzuki, Yoshitaka; Niizeki, Tomotake*; Kitagawa, Tomoya*; Nishikata, Kaori; Matsukura, Minoru*; Hasegawa, Yoshio*; Tanase, Masakazu*; Fukumitsu, Nobuyoshi*; Yamauchi, Yusuke*; Ariga, Katsuhiko*; et al.

no journal, , 

no abstracts in English

Oral presentation

Spin contrast variation neutron reflectometry for buried interface

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Torikai, Naoya*; Niizeki, Tomotake*

no journal, , 

Scattering of neutrons against protons remarkably depends on relative direction of their spins. Spin contrast variation is a technique to determine structure of composite materials using the polarization-dependent neutron scattering against proton. Recently, we have developed the first SCV neutron reflectivity technique for structural analysis of multilayer films. Structure of multilayer films can be determined from the proton-polarization dependent polarized neutron scatterings.

Oral presentation

Effect on sintering property of MoO$$_{3}$$ pellets of different MoO$$_{3}$$ powders

Nishikata, Kaori; Kimura, Akihiro; Kato, Yoshiaki; Kurosawa, Makoto; Ishida, Takuya; Tsuchiya, Kunihiko; Kakei, Sadanori*; Yoshinaga, Hideo*; Niizeki, Tomotake*; Hasegawa, Yoshio*

no journal, , 

no abstracts in English

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