22 results on '"Katagiri, K."'
Search Results
2. Time-resolved measurement of a shock-driven plasma target for interaction experiments between heavy ions and plasmas.
- Author
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Katagiri, K., Hasegawa, J., Nishinomiya, S., Ikagawa, H., and Oguri, Y.
- Subjects
- *
PARTICLES (Nuclear physics) , *SCISSION (Chemistry) , *ELECTRON distribution , *COLLISIONS (Nuclear physics) , *INTERMEDIATES (Chemistry) - Abstract
To observe nonlinearity in the stopping power of a nonideal plasma for heavy ions, we are planning a beam-plasma interaction experiment using 10-100 keV/u projectiles. For the interaction experiment, a nonideal hydrogen plasma target was developed by means of a shock technique. Time-resolved spectroscopic measurements determined the temporal evolution of the electron density and temperature of the shock plasma. These data revealed that the structure behind the shock front has an appropriate spatial and temporal distribution to be used as a target. We also evaluated the temporal evolution of the Coulomb coupling constant and the degree of ionization at a fixed position where the projectiles are injected. We discuss the feasibility of the nonlinear stopping experiment by evaluating the beam-plasma coupling constant expected from the measured plasma parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
3. Room and low temperature direct three-dimensional-strain measurements by neutron diffraction on as-reacted and prebent CuNb/Nb3Sn wire.
- Author
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Oguro, H., Awaji, S., Nishijima, G., Badica, P., Watanabe, K., Shikanai, F., Kamiyama, T., and Katagiri, K.
- Subjects
NEUTRON diffraction ,TEMPERATURE ,BENDING (Metalwork) ,SUPERCONDUCTIVITY ,STRAINS & stresses (Mechanics) - Abstract
We measured directly by neutron diffraction the axial and lateral residual strains for the prebent and the as-reacted CuNb/Nb
3 Sn wires at room temperature and at 7 K, in order to investigate the change of the residual strain with prebending treatment. In the axial direction of the wire, the residual strain was changed with 0.20% to the tensile side when measured at both temperatures, while in the lateral direction, the change was 0.08% and 0.03% to the compressive side for the measurements at RT and 7 K, respectively. From the obtained data, we estimated the deviatoric strain. At 7 K, the value is 0.40% for the as-reacted wires and it reduces to 0.19% when the prebending is applied with a strain [variant_greek_epsilon]pb =0.8%. These results suggest that the reduction of the residual strain in the axial direction as well as in the lateral direction, i.e., of the deviatoric strain is responsible for the observed enhancement in the superconducting properties of the prebent Nb3 Sn wires. In addition, we succeeded in the quantitative evaluation of the deviatoric strain dependence of the upper critical field for the practical Nb3 Sn wire. This is very important for the understanding of the general axial strain dependence of the superconducting properties. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF
4. Ion-production efficiency of a singly charged ion source developed toward a 11C irradiation facility for cancer therapy.
- Author
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Katagiri, K., Wakui, T., Hojo, S., Boytsov, A. Yu., Donets, E. D., Donets, E. E., Ramzdorf, A. Yu., Noda, A., Shirai, T., and Noda, K.
- Subjects
- *
HEAVY ions , *CANCER treatment , *IRRADIATION , *POSITRON emission tomography , *ELECTRON beams - Abstract
The ion-production efficiency of a newly developed singly charged ion source (SCIS) has been investigated to discuss the possibility of it being used in an isotope separation on-line system that provides 11C ions for heavy-ion cancer therapy with simultaneous verification of the irradiation field using positron emission tomography. The SCIS uses a low-energy hollow electron beam to produce singly charged carbon ions efficiently. To deliver sufficient 11C ions to the treatment room from a limited amount of 11C molecules, which are produced from a boron compound target and proton-beam irradiation via the 11B(p,n)11C reaction, the SCIS must have high ion-production efficiency. To realize this high efficiency, the SCIS was designed using a three-dimensional particle-in-cell code in previous work. With the fabricated SCIS, we performed experiments to measure the efficiency of producing C O 2 + ions from nonradioactive 12CO2 molecules and C+ ions from nonradioactive 12CH4 molecules. We found that the SCIS achieved efficiencies of ε C + = 4 × 1 0 − 3 (0.4%) for C+ production and ε C O 2 + = 0.107 (10.7%) for C O 2 + production. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. Singly charged ion source designed using three-dimensional particle-in-cell method.
- Author
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Katagiri, K., Noda, A., Wakui, T., Hojo, S., Miyahara, N., Boytsov, A. Yu., Donets, E. D., Donets, E. E., Ramzdorf, A. Yu., Shirai, T., and Noda, K.
- Subjects
- *
ISOTOPE separation , *HEAVY ions , *ELECTRON beams , *POSITRON emission tomography , *IONS - Abstract
A singly charged ion source (SCIS) has been designed using a newly developed three-dimensional particle-in-cell (PIC) code. The SCIS is to be used in an isotope separation on-line (ISOL) system that provides 11C ions for heavy-ion cancer therapy with simultaneous verification of the dose distribution using positron emission tomography. The SCIS uses low-energy electron beams to produce singly charged carbon ions efficiently and maintain a high vacuum in the ISOL system. Because the SCIS has to realize a production efficiency of 1% if its carbon ions are to be used in the ISOL system, a suitable design for the SCIS was investigated by using the developed PIC code to study the beam trajectories of the electrons and extracted ions. The simulation results show that hollow electron beams are produced in the designed SCIS resulting in a high effective electron current. The results also predict that the designed SCIS would realize ion-production efficiencies (IPEs) of εSCIS ≃ 6.7% for C O 2 + production from CO2 gas and εSCIS ≃ 0.1% for C+ production from CH4 gas. Moreover, to examine the validity of the developed code and confirm that the SCIS was able to be designed appropriately, the space-charge-limited current of the electron gun and the total IPE obtained by adding the IPEs of each ion were compared between the experiment and the simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
6. Relationship between strain effect and martensitic transformation in multifilamentary Nb3Sn wires.
- Author
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Watanabe, K., Katagiri, K., Noto, K., Awaji, S., Goto, K., Sadakata, N., Saito, T., and Kohno, O.
- Subjects
- *
MARTENSITIC transformations , *SUPERCONDUCTING composites , *SUPERCONDUCTORS , *CRITICAL currents - Abstract
Presents a study which clarified the relationship between the martensitic transformation and the strain effect in bronze-processed multifilamentary Nb[sub3]Sn superconducting wires. Details of the strain effects on critical current density for pure Nb[sub3]Sn and titanium-added (Nb, Ti)[sub3]Sn wires; Details of the experiment; Calculation of the residual strain in bronze-processed multifilamentary Nb[sub3]Sn superconducting wires.
- Published
- 1994
- Full Text
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7. Effects of neutron irradiation on the critical current of bronze processed multifilamentary Nb3Sn superconducting composites.
- Author
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Okada, T., Fukumoto, M., Katagiri, K., Saito, K., Kodaka, H., and Yoshida, H.
- Subjects
FAST neutrons ,IRRADIATION ,NIOBIUM ,SUPERCONDUCTING composites ,TIN - Abstract
Investigates the influence of fast neutron irradiation on critical current and its strain dependence in a bronze processed fine multifilamentary Nb[sub3]Sn superconducting composite. List of the specification of the bronze processed fine multifilamentary Nb[sub3]Sn superconducting composite wire specimen; Summary of material parameters of the multifilamentary Nb[sub3]Sn.
- Published
- 1988
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8. A singly charged ion source for radioactive 11C ion acceleration.
- Author
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Katagiri, K., Noda, A., Nagatsu, K., Nakao, M., Hojo, S., Muramatsu, M., Suzuki, K., Wakui, T., and Noda, K.
- Subjects
- *
SYNCHROTRONS , *ION sources , *RADIOACTIVE substances , *HEAVY ion accelerators , *NUCLEAR physics instruments , *IONIZATION (Atomic physics) - Abstract
A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
9. Cryogenic molecular separation system for radioactive 11C ion acceleration.
- Author
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Katagiri, K., Noda, A., Suzuki, K., Nagatsu, K., Boytsov, A. Yu., Donets, D. E., Donets, E. D., Donets, E. E., Ramzdorf, A. Yu., Nakao, M., Hojo, S., Wakui, T., and Noda, K.
- Subjects
- *
ISOTOPE separation , *POSITRON emission tomography , *CANCER treatment , *ION beams , *IRRADIATION , *VAPOR pressure - Abstract
A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
10. 14 MeV Neutron Irradiation Effect on Superconducting Magnet Materials for Fusion Device.
- Author
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Nishimura, A., Hishinuma, Y., Seo, K., Tanaka, T., Muroga, T., Nishijima, S., Katagiri, K., Takeuchi, T., Shindo, Y., Ochiai, K., Nishitani, T., and Okuno, K.
- Subjects
NEUTRON irradiation ,IRRADIATION ,NUCLEAR reactions ,SUPERCONDUCTING magnets ,ELECTROMAGNETS ,SUPERCONDUCTORS ,MAGNETIC fields ,FIELD theory (Physics) - Abstract
As a large-scale plasma experimental device is planned and designed, the importance of investigations on irradiation effect of 14 MeV neutron increases and an experimental database is desired to be piled up. Recently, intense streaming of fast neutron from ports are reported and degradation of superconducting magnet performance is anticipated. To investigate the pure neutron effect on superconducting magnet materials, a cryogenic target system was newly developed and installed at Fusion Neutronics Source in Japan Atomic Energy Research Institute. Although production rate of 14 MeV neutron is not large, only 14 MeV neutron can be supplied to irradiation test without gamma ray. Copper wires, superconducting wires, glass fiber reinforced composites are irradiated and the irradiation effects are characterized. At the same time, sensors for measuring temperature and magnetic field are irradiated and their performance was investigated after irradiation. This paper presents outline of the cryogenic target system and some irradiation test results. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
11. Irradiation Effect of 14 MeV Neutron on Interlaminar Shear Strength of Glass Fiber Reinforced Plastics.
- Author
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Nishimura, A., Hishinuma, Y., Seo, K., Tanaka, T., Muroga, T., Nishijima, S., Katagiri, K., Takeuchi, T., Shindo, Y., Ochiai, K., Nishitani, T., and Okuno, K.
- Subjects
IRRADIATION ,NEUTRAL beams ,PARTICLE beams ,NEUTRONS ,GAMMA rays ,ELECTROMAGNETIC waves ,IONIZING radiation - Abstract
Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and gamma ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and gamma ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength. A short beam test under three point bending was conducted at room temperature and 77 K. Neutron fluence of 3.91 × 1019 n/m2 was irradiated and the specimens did not show clear degradation of the strength. On the other hand, gamma ray irradiation of 1 MGy made the specimen weaker and 10 MGy caused delamination. Most of the specimens showed both of interlaminar cracking and bending fracture, but some specimens were fractured with irregular shear occurred on the planes connecting loading point and supporting points. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
12. On the Measurement of Tensile Properties of Superconducting NB3Sn Wires at Ambient Temperature and at Cryogenic Environment.
- Author
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Nyilas, A., Weiss, K., Thoener, M., Hojo, M., Osamura, K., and Katagiri, K.
- Subjects
STRAINS & stresses (Mechanics) ,MEASUREMENT ,SUPERCONDUCTORS ,LOADING & unloading ,LOW temperature engineering ,PHYSICAL sciences - Abstract
Within the frameworks of IEC/TC90 and VAMAS/TWA16 investigations have been initiated to establish a measurement guide for the determination of stress versus strain tensile properties of superconducting Nb3Sn wires of different designs. The main focus of this task was to develop a methodology to determine the correct elastic Young’s modulus, necessary for further wire qualification. To overcome the difficulty of the Young’s modulus determination with standard extensometers a procedure has been developed that uses the unloading compliance curves of several loading unloading cycles beyond the gross elastic limit. These unloading curves were analyzed to find a linear region, which is representative of the Young’s modulus value obtained from the zero offset line slope of the stress versus strain curve. The evaluation of the slopes at the vicinity of each unloading regime resulted in a set of virtual Young’s modulus data. The procedure has been investigated for different wires at ambient temperature and also finally at cryogenic regime. A guideline for the procedure has been worked out to serve as a preliminary draft towards the measurements of the mechanical properties of superconducting wires. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
13. Effects of Metal Powder Addition in Ni-Sheathed PIT MgB2 Tapes.
- Author
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Tachikawa, K., Yamada, Y., Katagiri, K., Kumakura, H., Iwamoto, A., and Watanabe, K.
- Subjects
METAL powders ,POWDER metallurgy ,ELECTRIC currents ,NICKEL ,SUPERCONDUCTIVITY ,SUPERCONDUCTORS ,CRYOELECTRONICS ,STRAINS & stresses (Mechanics) - Abstract
The effect of different metal powder additions on the transport current and stress/strain performance of ex-situ processed MgB2 tapes with Ni sheath has been studied. The metal powder added to the core exhibits elongated morphology after the fabrication. The addition of low melting point metal powder, e.g. In and Sn, produces an appreciable increase in the Jc of MgB2 core. An addition of 10 vol% In enhances Jc by a factor of 6 to 7 after the combination of rolling and annealing at 200 °C, up to the order of 105 A/cm2 at 0.5 T and 4.2 K. An addition of 10 vol% Sn enhances Jc by a factor of ∼ 3. The In and Sn additions also appreciably increase the n-value of the current-voltage transition. Both In and Sn metals infiltrate into gaps between MgB2 grains, improving the linkage of the grains. Current may transfer through the impregnated metal by the proximity effect. Furthermore, the metal powder addition appreciably improves the strain tolerance in MgB2 tapes. The low melting point metal powder addition is a relatively simple and easy approach to yield better transport current and stress/strain performance in ex-situ MgB2 tapes. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
14. Status of ion sources at National Institute of Radiological Sciences.
- Author
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Kitagawa, A., Fujita, T., Goto, A., Hattori, T., Hamano, T., Hojo, S., Honma, T., Imaseki, H., Katagiri, K., Muramatsu, M., Sakamoto, Y., Sekiguchi, M., Suda, M., Sugiura, A., and Suya, N.
- Subjects
ION sources ,ION accelerators ,ELECTROSTATICS ,CYCLOTRONS ,HEAVY ions ,THERAPEUTICS - Abstract
The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
15. Development of a compact ECR ion source for various ion production.
- Author
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Muramatsu, M., Hojo, S., Iwata, Y., Katagiri, K., Sakamoto, Y., Takahashi, N., Sasaki, N., Fukushima, K., Takahashi, K., Suzuki, T., Sasano, T., Uchida, T., Yoshida, Y., Hagino, S., Nishiokada, T., Kato, Y., and Kitagawa, A.
- Subjects
ION sources ,ION beams ,ELECTRON cyclotron resonance sources ,MAGNETIC fields ,FARADAY cup ,LINEAR accelerators - Abstract
There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
16. Spreading behavior of an impacting drop on a structured rough surface.
- Author
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Sivakumar, D., Katagiri, K., Sato, T., and Nishiyama, H.
- Subjects
- *
DROPLETS , *SURFACES (Physics) , *VIDEO microscopy , *DYNAMICS , *FLUIDS - Abstract
The spreading of water drops impinging on structured rough surfaces is studied experimentally. The rough surfaces are specially prepared with a regular pattern of surface asperities. The arrangement of the square-shaped surface asperities creates channel-like grooves on the surface. A video microscope along with a controlled light exposure system is used to construct the image sequences of the spreading process. The images are digitally analyzed to measure the temporal variation of the spreading drop diameter 2R. Results are obtained for three rough surfaces with varying asperity heights in the range of 100–500 μm and for different impact drop conditions with Weber number We in the range of 35–225. The results on the temporal variation of 2R show that, on the structured rough surfaces, the spreading occurs simultaneously both inside and above the texture pattern of the surfaces. For a given surface geometry, the volume of liquid flowing inside the grooves of the surface increases with increasing We. Consequently, the values of 2R measured inside the texture pattern are larger than those measured above the texture pattern, and their difference increases with increasing We. The arrangement of the surface asperities influences the spreading pattern of an impacting drop spreading axisymmetrically. For the texture geometry used in the present study, the spreading pattern resembles a regular rhombus shape for the impact of low We drops and becomes complex at high We. The spreading distances, measured both inside and above the texture pattern of the structured rough surfaces, are nearer to the measurements recorded on the smooth surface if the asperity height of the rough surface is smaller than the thickness of the spreading liquid lamella; however, the surface asperities influence the spreading pattern drastically and create a liquid splash. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
17. Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron.
- Author
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Hojo, S., Katagiri, K., Nakao, M., Sugiura, A., Muramatsu, M., Noda, A., Okada, T., Takahashi, Y., Komiyama, A., Honma, T., and Noda, and K.
- Subjects
- *
ELECTRON cyclotron resonance sources , *ION sources , *MAGNETIC materials , *CYCLOTRON resonance , *ION beams , *PROTONS - Abstract
The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C4+ ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 µAf o r proton and deuteron, 50 µAf o rC4+, for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
18. Ion-production efficiency of a singly charged ion source developed toward a 11 C irradiation facility for cancer therapy.
- Author
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Katagiri K, Wakui T, Hojo S, Boytsov AY, Donets ED, Donets EE, Ramzdorf AY, Noda A, Shirai T, and Noda K
- Subjects
- Equipment Design, Radiochemistry instrumentation, Carbon Radioisotopes therapeutic use, Heavy Ion Radiotherapy, Neoplasms radiotherapy, Radiochemistry methods
- Abstract
The ion-production efficiency of a newly developed singly charged ion source (SCIS) has been investigated to discuss the possibility of it being used in an isotope separation on-line system that provides
11 C ions for heavy-ion cancer therapy with simultaneous verification of the irradiation field using positron emission tomography. The SCIS uses a low-energy hollow electron beam to produce singly charged carbon ions efficiently. To deliver sufficient11 C ions to the treatment room from a limited amount of11 C molecules, which are produced from a boron compound target and proton-beam irradiation via the11 B(p,n)11 C reaction, the SCIS must have high ion-production efficiency. To realize this high efficiency, the SCIS was designed using a three-dimensional particle-in-cell code in previous work. With the fabricated SCIS, we performed experiments to measure the efficiency of producing CO2 + ions from nonradioactive12 CO2 molecules and C+ ions from nonradioactive12 CH4 molecules. We found that the SCIS achieved efficiencies of εC =4×10+ -3 (0.4%) for C+ production and εCO =0.107 (10.7%) for CO2 + 2 + production.- Published
- 2019
- Full Text
- View/download PDF
19. Electron string ion sources for carbon ion cancer therapy accelerators.
- Author
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Boytsov AY, Donets DE, Donets ED, Donets EE, Katagiri K, Noda K, Ponkin DO, Ramzdorf AY, Salnikov VV, and Shutov VB
- Subjects
- Magnetic Fields, Electrons, Heavy Ion Radiotherapy instrumentation, Neoplasms radiotherapy, Particle Accelerators instrumentation
- Abstract
The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C(4+) and C(6+) ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10(10) C(4+) ions per pulse and about 5 × 10(9) C(6+) ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10(11) C(6+) ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the (11)C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C(4+) ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of (11)C, transporting to the tumor with the primary accelerated (11)C(4+) beam, this efficiency is preliminarily considered to be large enough to produce the (11)C(4+) beam from radioactive methane and to inject this beam into synchrotrons.
- Published
- 2015
- Full Text
- View/download PDF
20. A simple algorithm for beam profile diagnostics using a thermographic camera.
- Author
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Katagiri K, Hojo S, Honma T, Suzuki K, Noda A, and Noda K
- Abstract
A new algorithm for digital image processing apparatuses is developed to evaluate profiles of high-intensity DC beams from temperature images of irradiated thin foils. Numerical analyses are performed to examine the reliability of the algorithm. To simulate the temperature images acquired by a thermographic camera, temperature distributions are numerically calculated for 20 MeV proton beams with different parameters. Noise in the temperature images which is added by the camera sensor is also simulated to account for its effect. Using the algorithm, beam profiles are evaluated from the simulated temperature images and compared with exact solutions. We find that niobium is an appropriate material for the thin foil used in the diagnostic system. We also confirm that the algorithm is adaptable over a wide beam current range of 0.11-214 μA, even when employing a general-purpose thermographic camera with rather high noise (ΔT(NETD) ≃ 0.3 K; NETD: noise equivalent temperature difference).
- Published
- 2014
- Full Text
- View/download PDF
21. (11)CH4 molecule production using a NaBH4 target for (11)C ion acceleration.
- Author
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Katagiri K, Nagatsu K, Minegishi K, Suzuki K, Hojo S, Muramatsu M, Honma T, Kitagawa A, Noda A, and Noda K
- Subjects
- Carbon Radioisotopes, Borohydrides, Methane, Particle Accelerators instrumentation
- Abstract
Solid-state materials suitable for use as proton irradiation targets were investigated for producing high-purity (11)CH4 molecules for heavy-ion cancer therapy. The radioactivity of gas produced by proton irradiation was measured for several target materials. Also, the radioactive molecular species of the produced gas were analyzed by radio gas chromatography. We found that 5 × 10(12) (11)C molecules could be collected by proton irradiation on a NaBH4 target. We also found that the (11)CH4 molecules were produced and collected directly from the irradiated target, owing to the hydrogen atoms bound in the solid-state NaBH4.
- Published
- 2014
- Full Text
- View/download PDF
22. Numerical studies of transient gain reduction process in a multi-wire proportional chamber.
- Author
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Katagiri K, Furukawa T, and Noda K
- Abstract
A gain reduction process caused by successive beam irradiation in a multi-wire proportional chamber was numerically investigated to clarify the relations between the gas gain variation and the ion density distribution. A numerical code was developed based on a two-dimensional drift-diffusion model in order to evaluate the ion and electron density distributions and the electric field variation caused by the space charge effect. In order to consider the gain reduction process which occurs under the high rate and successive irradiation, the simulations were performed for the time period of ∼10-100 μs, which is much longer than the time required for ions to travel from an anode to a cathode. The numerical simulation results showed that for the low gas gain regime of ∼10, quasi-stationary density distribution of the ions was formed by the high-rate beams of ∼10(8)-10(10) particles per second, and that the transient variation of the gas gain became constant after establishment of the quasi-stationary ion density distributions.
- Published
- 2011
- Full Text
- View/download PDF
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