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Systematic Study on KeV-Neutron Capture Reaction of Se Isotopes
M. Igashira,S. Kamada,T. Katabuchi,M. Mizumoto 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Systematic measurements and calculations of neutron capture cross sections and capture gamma-ray spectra of all stable Se isotopes ^(74, 76, 77, 78, 80, 82)Se were performed in a neutron energy region from 10 to 600 keV, using a pulsed neutron source by the ^7Li(p,n)^7Be reaction. Highly isotopically enriched Se samples and standard Au samples were used. The capture gamma rays from each sample were detected with an anti-Compton NaI(Tl) spectrometer by means of a time-of-flight method. The capture cross sections were derived by using a pulse-height weighting technique and the standard capture cross sections of ^(197)Au. The capture gamma-ray spectra were obtained by unfolding the observed capture gamma-ray pulse-height spectra. In the calculations, a computer code, POD, was utilized. The calculated results were compared with the experimental results. The present experimental and calculated results were compared with previous measurements and evaluated values.
Analysis of Radial Air-shear Force on Magnetic Disks for Reducing the Spin-off of Lubricants
M. KURITA,H. SHIMIZU,M. MIZUMOTO,Y. OOTANI 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10
To reduce the spin-off of lubricants on a magnetic disk, which is caused by the radial component of shear force between the disk and air, we analyzed the air-velocity distribution and the air-shear force by three-dimensional large-eddy simulation (LES). This sensitivity analysis, on five design parameters, showed that disk/arm clearance and ann thickness have a greater effect on the mean radial air-shear force than the other parameters. The force on a disk optimized according to the optimum parameters is 12% less than the force on a conventional disk.
Selection of Particle Beam vs. Photon Beam Radiation Therapy for HCC: Japanese Experience
( Hideyuki Sakurai ),( M Iizumi ),( S Shimizu ),( H. Numajiri ),( M. Mizumoto ),( K. Nakai ),( T. Okumura ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Radiation therapy (RT) using conventional fractionation has not been thought to be curative enough for hepatocellular carcinoma (HCC) and it has not been performed as a high priority in comparison to other standard treatments, such as surgery, percutaneous ablation and transcatheter approach. Because the liver is high sensitive to radiation, especially for patients with liver cirrhosis, non-irradiated normal liver volume must be preserved as much as possible when curative radiation is given for HCC. Since many technological progress has been made in radiation oncology in recent years, RTs are used as an important curative treatment option for liver cancer. Stereotactic body radiotherapy (SBRT), which is included in Japanese national health insurance system, is a technique to accurately concentrate doses three-dimensionally on the target with short-term irradiation of 1-2 weeks. This technique can be used for relatively small tumors less than 5 cm with about 90% local control. Recently, Hara K. et al. reported survival result of SBRT comparing radiofrequency ablation using propensity score analysis, and they concluded that SBRT appears to be an acceptable alternative treatment option for patients who are not candidates for RFA. In addition, in Japan, muticenter prospective study of SBRT for untreated solitary primary HCC, so called STRSPH study, is ongoing. Eligible patients are untreated solitary, Child-Pugh score ≦7, Diameter: 1-5cm, UICC 7th. T1, T2, T3bN0M0, performance status score of 0-2, and 20-85 year-old. The primary endpoint / number of cases of this study are 3-year overall survival / 60 cases. Particle beam therapy (PBT: proton beam therapy, heavy ion beam therapy) has unique character of radiation dose distribution, which is called Bragg peak. PBT can accumulate more dose to the target with minimizing normal liver dose. Primary liver tumor is an important indication that has been specified to be of the highest priority by the American Society for Radiology and Oncology (ASTRO). In fact, most of the studies on PBT for HCC are published by Japan, and rather highly evaluated abroad. Eighteen proton facilities and 6 heavy ion facilities are working now in Japan. The local control rate was approximately 90% and the 5-year survival rate was reported to be approximately 50%. According to the results of our hospital, PBT can control 90% of a large tumor of 10 cm or more. Clinical studies of PBT report favorable therapeutic effects, even for not only large tumors but also tumors in elderly patient. In addition, PBT has been clearly shown to play an important role in the treatment of HCC-related portal vein tumor thrombosis (PVTT). When applied as a curative treatment for bulky tumors with portal vein embolism, median survival time of 27 months has been obtained in our study. The clinical study comparing proton vs surgery, which is non-randomized trial using propensity score, is ongoing in Japan (JCOG1315C). Japanese Society for Radiation Oncology (JASTRO) defined identical rule for indication and treatment method in PBT for HCC, and the all data should be registered in the data-base since 2016. We are facing an aging society, although there are indications of surgery and other local treatment, the number of patients who choose curative radiation therapy due to aging and co-existing disease is increasing. But, the history of radical RT for HCC is still short, and sufficient consensus has not been obtained regarding the criteria for its therapeutic indication. RT may become an option for curative local treatment of HCC, but no specific role for RT has been described in the Japanese treatment guidelines. In the future, it is important to proceed with research to clarify the indication of curative radiation therapy, keeping in mind the comparison with other therapies.
Y. Kiyanagi,K. Kino,M. Furusaka,F. Hiraga,T. Kamiyama,K. Kato,M. Igashira,T. Katabuchi,M. Mizumoto,M. Oshima,H. Harada,J. Katakura,K. Furutaka,S. Goko,A. Kimura,T. Kin,F. Kitatani,M. Koizumi,S. Nakamu 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
A project on the comprehensive nuclear data research for the development of the advanced reactor systems had been executed successfully by eight organizations from 2005 to 2009. In this project, we constructed a pulsed neutron beamline that was aimed to obtain neutron capture cross-sections of long-lived fission products and minor actinides accurately. The energy spectra, spatial distributions, and pulses of the beam were studied by measurements and simulation calculations, and they were found to be consistent with those of the beamline design. In this paper, we present the overview of the project and the properties of the neutron beam provided by this beam line.
Measurement of Neutron Capture Cross Section and Gamma-Ray Spectra of ^(88)Sr in keV Energy Region
T. Katabuchi,N. C. Hai,M. Igashira,S. Kamada,M. Tajika,M. Mizumoto 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The neutron capture cross section of ^(88)Sr at incident neutron energies E_n = 10 - 89 keV and 510 keV has been measured by the time-of-flight method. Capture γ-rays were detected with an anti-Compton NaI(Tl) spectrometer and the pulse height weighting technique was applied to derive the neutron cross section as a function of incident neutron energy. Capture γ-ray spectra were also measured. The obtained capture cross section was compared with previous experimental data and evaluated data from ENDF/B-VII.0.
Study of Neutron Capture Reactions Using the 4π Ge Spectrometer
H. Harada,S. Goko,A. Kimura,M. Ohta,M. Oshima,F. Kitatani,M. Igashira,T. Katabuchi,M. Mizumoto,T. Ohsaki,J. Hori,T. Fujii,K. Takamiya,J. Goto,Y. Kiyanagi,K. Kino,M. Furusaka,F. Hiraga,T. Kamiyama 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The 4π Ge spectrometer composed of 22-30 Ge detectors was developed, and it has been used to study neutron capture reactions with a neutron time-of-flight (TOF) technique. Since the distances between the sample position and the Ge detectors are variable, it can be used as a multifunctional spectrometer. At first, it was used as a sum energy spectrometer, and resonances in ^(nat)Ag were identified as those of ^(1070Ag or ^(109)Ag. In second, it was used to deduce γ-ray intensity distribution for each resonance, and the results for ^(238)U were presented. In third, it was used to measure neutron capture cross sections of minor actinides and fission products at the electron linear accerelator facility of KURRI and at the accurate neutron-nucleus reaction measurement instrument (ANNRI) in MLF of J-PARC The preliminary results are discussed mainly based on measurements of neutron capture cross section for ^(241)Am, together with related techniques.
Measurements of Neutron-Capture Cross Sections of ^(244)Cm and ^(246)Cm at J-PARC/MLF/ANNRI
A. Kimura,K. Furutaka,S. Goko,H. Harada,T. Kin,F. Kitatani,M. Koizumi,S. Nakamura,M. Ohta,M. Oshima,Y. Toh,T. Fujii,S. Fukutani,J. Hori,K. Takamiya,M. Igashira,T. Katabuchi,M. Mizumoto,T. Kamiyama,K. 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
For developments of innovative nuclear reactors, strong demands exist for the improvement of the accuracy of the neutroncapture cross sections of minor actinides (MAs) and long-lived fission products. We have constructed a Ge-spectrometer using the Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) in the J-PARC materials and life science experimental facility (MLF). Preliminary neutroncapture cross sections of ^(244)Cm and ^(246)Cm were obtained in the neutron energy range from 1.0 eV up to 300 eV.
Measurements of Neutron-Capture Cross Sections of Palladium Isotopes at the J-PARC/MLF/ANNRI
S. Nakamura,K. Furutaka,S. Goko,H. Harada,A. Kimura,T. Kin,F. Kitatani,M. Koizumi,M. Ohta,M. Oshima,Y. Toh,J. Hori,T. Fujii,S. Fukutani,K. Takamiya,M. Igashira,T. Katabuchi,M. Mizumoto,T. Kamiyama,K. 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The operation of a new experimental apparatus called ``Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI)''in the Material and Life science experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC) has been started for neutroncapture crosssection measurements of minor actinides and long-lived fission products. As a part of the measurements, we have measured the time-of-flight spectra of palladium-105, 106, 107 and 108 with a ``4π Ge spectrometer'' installed at the ANNRI. We obtained preliminary results of the cross sections for palladium-107 and 105 in neutron energies ranging from 0.1 eV to 300 eV.
T. Kin,K. Furutaka,S. Goko,H. Harada,A. Kimura,F. Kitatani,S. Nakamura,M. Ohta,M. Oshima,Y. Toh,J. Hori,M. Igashira,T. Katabuchi,M. Koizumi,M. Mizumoto,T. Kamiyama,K. Kino,Y. Kiyanagi 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
A ``4π germanium spectrometer'' was developed for measurements of neutron capture cross sections of minor actinides and long-lived fission products. It was installed on the Beam Line No. 04 of the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. The time-of-flight method is used to measure the cross sections. To obtain characteristics of the spectrometer, a measurement was done of prompt gamma rays emitted following neutron capture reactions of gold whose cross section was well studied. In the present paper, we show the procedure of analysis of the data obtained with the spectrometer and discuss the characteristics to measure neutron capture cross section.
J. Hori,K. Furutaka,S. Goko,H. Harada,A. Kimura,T. Kin,F. Kitatani,M. Koizumi,S. Nakamura,M. Ohta,M. Oshima,Y. Toh,M. Igashira,T. Katabuchi,M. Mizumoto,T. Kamiyama,K. Kino,Y. Kiyanagi 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The prompt gamma rays from the neutron capture reactions by ^(91)Zr and ^(96)Zr were measured. A neutron time-of-flight (TOF) method was adopted with a 4π Ge spectrometer installed at the Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) in the J-PARC Material and Life science experimental Facility (MLF). The gamma-ray pulse-height spectra corresponding to the 292-eV resonance of ^(91)Zr and the 301-eV resonance of ^(96)Zr were obtained by gating on the TOF regions, respectively. The relative intensities of those transitions were derived. Moreover, we have demonstrated the nuclide discrimination technique by identifying ^(91)Zr resonances (isotopic composition of 5.3%) in the measurement of ^(96)Zr sample This technique can be applicable to the neutron capture measurement for a small amount of sample expected in case of long-lived fission products (LLFPs) such as ^(93)Zr.