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Development of vehicles that are powered by photovoltaics (PV) is desirable, and is crucial for reduction in CO2 emissions from the transport sector to realize a decarbonized society. Our investigations show that the majority of the passenger cars that cruise only with solar energy can be realized by installing a high-efficiency PV module. Although the Toyota Prius demonstration car, which is equipped with a 860 W rated-output power PV module, has shown a 36.6 km dâˆ'1 PV-powered driving range at solar irradiance of 6.2 kWh mâˆ'2 dâˆ'1, practical driving ranges of PV-powered vehicles are shown to be shorter than the estimated values due to some losses of solar cell modules, such as temperature rise under sunny conditions. In this paper, we conduct a systematic analysis of the effects of these losses on the PV-powered driving range in order to obtain guidelines for the development of highly efficient solar cell modules for vehicle integrated applications. The analytical results show that the IIIâ€"V compound solar cell modules have more suitable properties compared to other cells because of their higher potential conversion efficiencies of 37% with a smaller temperature coefficient of âˆ'0.19% °Câˆ'1 compared to âˆ'0.29% °Câˆ'1 for Si back contact solar cell modules and âˆ'0.26% °Câˆ'1 for Si heterojunction solar cell modules. Our theoretical calculations that take these losses into account suggest that installing the IIIâ€"V-based triple-junction solar cell modules provides a potential PV-powered driving range of 30 km dâˆ'1 on average, and more than 50 km dâˆ'1 on a sunny day under the irradiation conditions in Japan. [ABSTRACT FROM AUTHOR]

A workshop was recently held at Nagoya University (2017 October 31–November 2), sponsored by the Center for International Collaborative Research, at the Institute for Space-Earth Environmental Research, Nagoya University, Japan, to quantitatively compare the performance of today’s operational solar flare forecasting facilities. Building upon Paper I of this series, in Paper II we described the participating methods for this latest comparison effort, the evaluation methodology, and presented quantitative comparisons. In this paper, we focus on the behavior and performance of the methods when evaluated in the context of broad implementation differences. Acknowledging the short testing interval available and the small number of methods available, we do find that forecast performance: (1) appears to improve by including persistence or prior flare activity, region evolution, and a human “forecaster in the loop”; (2) is hurt by restricting data to disk-center observations; (3) may benefit from long-term statistics but mostly when then combined with modern data sources and statistical approaches. These trends are arguably weak and must be viewed with numerous caveats, as discussed both here and in Paper II. Following this present work, in Paper IV (Park et al. 2019) we will present a novel analysis method to evaluate temporal patterns of forecasting errors of both types (i.e., misses and false alarms). Hence, most importantly, with this series of papers, we demonstrate the techniques for facilitating comparisons in the interest of establishing performance-positive methodologies. [ABSTRACT FROM AUTHOR]

The combination of the high intensity proton beam facilities and massive detectors for precision measurements of neutrino oscillation parameters including the charge-parity violating (CPV) phase will open the door to help make beyond the standard model (BSM) physics reachable even in low energy regimes in the accelerator-based experiments. Large-mass detectors with highly precise tracking and energy measurements, excellent timing resolution, and low energy thresholds will enable the searches for BSM phenomena from cosmogenic origin, as well. Therefore, it is also conceivable that BSM topics in the next-generation neutrino experiments could be the dominant physics topics in the foreseeable future, as the precision of the neutrino oscillation parameter and CPV measurements continue to improve.This paper provides a review of the current landscape of BSM theory in neutrino experiments in two selected areas of the BSM topics—dark matter and neutrino related BSM—and summarizes the current results from existing neutrino experiments to set benchmarks for both theory and experiment. This paper then provides a review of upcoming neutrino experiments throughout the next 10 to 15 year time scale and their capabilities to set the foundation for potential reach in BSM physics in the two aforementioned themes. An important outcome of this paper is to ensure theoretical and simulation tools exist to carry out studies of these new areas of physics, from the first day of the experiments, such as Deep Underground Neutrino Experiment in the U.S. and Hyper-Kamiokande Experiment in Japan. [ABSTRACT FROM AUTHOR]

Neutron beams have been providing indispensable tools for a wide range of fields in modern science and engineering. Recently, a new type of pulsed neutron source has been developed, known as laser-driven neutron source (LDNS). The LDNSs utilize laser-accelerated ions, including protons and deuterons as a primary beam and generate neutrons from a secondary target (lithium, beryllium, etc) via a nuclear reaction. Applying an additional moderator part, LDNSs can provide a broad energy range of neutrons (meV ∼ MeV). This paper aims to introduce the current status of LDNS and the results of application-oriented experiments implemented at the Institute of Laser Engineering (ILE) of Japan. [ABSTRACT FROM AUTHOR]

Based on the results of the IFMIF/EVEDA project in the broader approach (BA) activities, the conceptual design of the Advanced Fusion Neutron Source (A-FNS) to obtain irradiation data of DEMO blanket materials is under consideration in Japan. This paper describes the progress of the A-FNS conceptual design, which consists of a 40 MeV, 125 mA deuteron beam, a liquid lithium target system, and a test and post-irradiation test facilities. the main objectives of the A-FNS are the acquisition of RAFM irradiation data up to 2035 and the tritium recovery test on the blanket. In addition, it is expected to be used for various neutron researches. The technical design activities of the A-FNS are focused on improvement of the lithium target design, review of impurity criteria, remote handling, and irradiation application plan. [ABSTRACT FROM AUTHOR]

The radiation doses from natural radiation sources in Japan are reviewed using the latest knowledge. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation, and ingestion as natural sources. In this paper, the total annual effective dose from cosmic-ray exposure is evaluated as 0.29 mSv. The arithmetic mean of the annual effective dose from external exposure to terrestrial radiation is 0.33 mSv for the Japanese population using the data of nationwide surveys by the National Institute of Radiological Sciences. Previously in Japan, although three different groups have conducted nationwide indoor radon surveys using passive-type radon monitors, to date only the Japan Chemical Analysis Center (JCAC) has performed a nationwide radon survey using a unified method for radon measurements conducted indoor, outdoor, and in the workplace. Consequently, the JCAC results are used for the annual effective dose from radon and that for radon inhalation is estimated as 0.50 mSv using a current dose conversion factor. In this paper, UNSCEAR values are used for the mean indoor and outdoor thoron-progeny concentrations, and the annual effective dose from thoron is reported as 0.09 mSv. Thus, the annual effective dose from radon and thoron inhalation is 0.59 mSv. From a JCAC large-scale survey of foodstuffs, the committed effective dose from the main radionuclides in dietary intake is 0.99 mSv. Finally, the Japanese population dose from natural radiation is given as 2.2 mSv, which is similar to the reported global average of 2.4 mSv. [ABSTRACT FROM AUTHOR]

Many students majoring in science may not have a chance to directly observe spherical aberration or understand its mechanism during their study of optics. In this paper, the author reports a method of directly observing spherical aberration under a microscope by comparing focal spot images of spherical mirrors and parabolic mirrors made of celluloid concave micromirrors, fabricated by Suzuki's universal microprinting method, invented in Japan in 1930. The application of concave micromirrors to the optical-axis alignment of a microscope light source is also explained. Furthermore, the application of concave micromirrors to a substrate of micro-watch glass, used in microorganism microscopy, is also explained. [ABSTRACT FROM AUTHOR]

This study quantitatively derives a principle for super-high-accuracy angular indexing using an index table formulation, and verifies it in a mathematical simulation. An index table is a rotary table installed on a machine tool. Its main function is to fix the angle position of the rotational shaft. The angle position is measured by a rotary encoder built into the rotary table. The rotary encoder is required to measure the angle with high accuracy. In previous studies, the performance of the rotary encoder has been improved by two methods: direct reduction of the angle error factors, and self-calibration. The angle accuracy in these methods varies from 0.1 to 0.4 arcsecs during one rotation. Instead, the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) in Japan has developed an angular indexing device with super high accuracy, which measures the static angle position to 0.01 arcsecs. Although the principle of super-accurate angular indexing has been qualitatively discussed, a quantitative understanding is lacking. In the present paper, the principle is derived from a Fourier transform analysis, exploiting the circular closure characteristic of the angle error. The principle is then investigated in mathematical simulation of the quantitative formulation. The simulation has obtained positive results to derive the principle quantitatively. [ABSTRACT FROM AUTHOR]

Two hundred and twenty-five papers relevant to fusion technology and engineering were presented at the 27th IAEA Fusion Energy Conference. The ITER project has reached 57.4% of the total construction work scope through to first plasma. Construction of ITER is indeed progressing at full speed, with some ITER components having already been manufactured, such as the toroidal field coil structures and the gyrotrons of the electron cyclotron heating and current drive system, as a result of decades of technological development. Construction of JT-60SA and WEST is also progressing on schedule to support ITER in various engineering and physics aspects. The EU and Japan are advancing with their pre-conceptual designs for DEMO, and the experience and lessons learned from ITER are already being applied to both designs. China reported on the status of the China Fusion Engineering Test Reactor engineering design. One of the technical issues evident from these DEMO designs is the interfacing of the plasma-facing, in-vessel components with plasmas. Advanced plasma-facing elements having liquid metals and an advanced in situ boron coating technology were applied to existing fusion reactors, the results of which were reported at this conference. It was also reported that commissioning of the injector for the International Fusion Materials Irradiation Facility engineering validation and engineering design activities (IFMIF/EVEDA) project has been completed and testing of the Radio Frequency Quadrupole accelerator has begun. Europe and Japan presented their plans to construct neutron irradiation test facilities: the DEMO-Oriented Neutron Source (DONES) and Advanced Fusion Neutron Source (A-FNS), respectively. A new strategy based on a probability-based design method was proposed to mitigate the difficulty of defining the allowable limit for irradiation-induced degradation with limited empirical evidence. [ABSTRACT FROM AUTHOR]

JT-60SA, the largest tokamak that will operate before ITER, has been designed and built jointly by Japan and Europe, and is due to start operation in 2020. Its main missions are to support ITER exploitation and to contribute to the demonstration fusion reactor machine and scenario design. Peculiar properties of JT-60SA are its capability to produce long-pulse, high-β, and highly shaped plasmas. The preparation of the JT-60SA Research Plan, plasma scenarios, and exploitation are producing physics results that are not only relevant to future JT-60SA experiments, but often constitute original contributions to plasma physics and fusion research. Results of this kind are presented in this paper, in particular in the areas of fast ion physics, high-beta plasma properties and control, and non-linear edge localised mode stability studies. [ABSTRACT FROM AUTHOR]

Heating neutral beam (HNB) injectors, necessary to achieve burning conditions and to control plasma instabilities in ITER, are characterized by such demanding parameters that a neutral beam test facility (NBTF) dedicated to their development and optimization is being realized in Padua (Italy) with direct contributions from the Italian government (through Consorzio RFX as the host entity) and the ITER international organization (with kind contributions from the ITER domestic agencies of Europe, Japan and India) and technical and scientific support from various European laboratories and universities. The NBTF hosts two experiments: SPIDER, devoted to ion source optimization for the required source performance, and MITICA, the full-size prototype of the ITER HNB, with an ion source identical to SPIDER. This paper gives an overview of the progress towards NBTF realization, with particular emphasis on issues discovered during this phase of activity and on solutions adopted to minimize the impact on the schedule and maintain the goals of the facilities. The realization of MITICA is well advanced; operation is expected to start in 2023 due to the long procurement time of the in-vessel mechanical components. The beam source power supplies, operating at 1 MV, are in an advanced phase of realization; all high-voltage components have been installed and the complex insulation test phase began in 2018. At the same time, construction and installation of SPIDER plant systems was successfully completed with their integration into the facility. The mechanical components of the SPIDER ion source were installed inside the vessel and connected to the plants. Integrated commissioning with the control, protection and safety systems ended positively and the first experimental phase has begun. The first results of the SPIDER experiment, with data from operational diagnostics, and the plans for the 1 MV insulation tests on the MITICA high-voltage components are presented. [ABSTRACT FROM AUTHOR]

The dissociation and ionization dynamics of CF3I and CH3I molecules were investigated using a pump-and-probe technique that employs a soft x-ray free-electron laser (SACLA) in Japan. First, time-resolved inner-shell photoelectron spectroscopy was employed to observe the ultrafast reaction of CF3I by monitoring iodine 4d electrons. The change in the I 4d state observed in the photoelectron spectra is found to occur with a rise time τ of approximately 40 fs after a pump laser pulse, which is faster than that observed when an ultrafast gas-phase electron diffraction technique is employed. This implies that the inner-shell photoelectron spectroscopy is more sensitive to the potential surface near the Franck–Condon region. Second, a strong laser intensity at 266 nm, corresponding to a power density of 1.9 × 1014 W cm−2, can easily ionize CH3I molecules via multiphoton ionization processes, and the time dependence of the valence photoelectron spectra clearly shows that at the picosecond timescale, this pump laser pulse causes spectral peaks to shift owing to space-charge effects in response to the large amount of ions generated. Thus, the SACLA can be a useful tool to investigate not only the dynamical process of molecular dissociation but also the ionization process through the shift in the peaks of photoelectron spectra. [ABSTRACT FROM AUTHOR]

A development project for hypo-fractionated multi-ion therapy has been initiated at the National Institute of Radiological Sciences in Japan. In the treatment, helium, carbon, oxygen, and neon ions will be used as primary beams with pencil beam scanning. A ripple filter (RiFi), consisting of a thin plastic or aluminum plate with a fine periodic ridge and groove structure, has been used to broaden the Bragg peak of heavy-ion beams in the beam direction. To sufficiently broaden the Bragg peak of helium-, carbon-, oxygen-, and neon-ion beams with suppressed lateral scattering and surface dose inhomogeneity, in this study, we tested a plate made of a lung substitute material, Gammex LN300, as the RiFi. The planar integrated dose distribution of a 183.5 MeV u−1 neon-ion beam was measured behind a 3 cm thick LN300 plate in water. The Bragg peak of the pristine beam was broadened following the normal distribution with the standard deviation σ value of 1.29 mm, while the range of the beam was reduced by 8.8 mm by the plate. To verify the LN300 performance as the RiFi in multi-ion therapy, we measured the pencil beam data of helium-, carbon-, oxygen- and neon-ion beams penetrating the 3 cm thick LN300 plate. The data were then modeled and used in a treatment planning system to achieve a uniform 10% survival of human undifferentiated carcinoma cells within a cuboid target by the beam for each of the different ion species. The measured survival fractions were reasonably reproduced by the planned ones for all the ion species. No surface dose inhomogeneity was observed for any ion species even when the plate was placed close to the phantom surface. The plate made of lung substitute material, Gammex LN300, is applicable as the RiFi in multi-ion therapy with helium-, carbon-, oxygen- and neon-ion beams. [ABSTRACT FROM AUTHOR]

A new traceability chain for luminance scale is proposed for light-emitting diode (LED) luminance measurement, which utilizes a newly developed LED-based luminance standard source (luminance standard LED) as a transfer standard. Compared with conventional traceability chains for LED luminance measurement that rely on either a luminance meter to transfer the scale from the primary to the user level, the proposed scheme has a two-fold advantage. Firstly, color correction is made at the traceability source and the user is freed from performing this complicated task. Secondly, the luminance standard LED acts as the reference source for comparison measurement with a luminance meter and no other extended source facilities such as integrating spheres are necessary at the user site. Performance evaluation of the luminance standard LEDs showed spatial uniformity better than ±2.0% within a 7 mm diameter area and temporal stability of 0.01% during an 8 h operation, which verified the LEDs' capability to serve as a reference standard source. Calibration of the luminance standard LED was performed on the luminance scale realized by illuminance to luminance conversion, and the calibration uncertainty was estimated to be U = 1.4% to 1.7% (k = 2) at the traceability source. It is expected that this will enable users to obtain luminance measurement uncertainties comparable to the conventional traceability schemes while profiting from the high practicability that the proposed scheme provides. The luminous standard LEDs are now used in a new traceability chain in Japan, contributing to improved reliability of the luminance measurement of a wide range of LED-based products such as displays. [ABSTRACT FROM AUTHOR]

The Quasi-Zenith Satellite System (QZSS) from Japan will supplement the global positioning system (GPS) for more accurate and stable positioning, navigation and timing services. However, QZSS and GPS measurements are not free of inter-system bias (ISB) for various receiver brands. After estimating and clustering the receiver ISB values of GPS and QZSS for all three overlapping frequencies L1, L2 and L5, we show that the code ISB of the receivers can have at least two groups and the firmware versions of the groups may overlap with each other, making the look-up-table calibration difficult. Therefore, we propose to discriminate one code ISB value from the other for a specific receiver by the observations of a few epochs so that precise calibration can be implemented within a short time. The phase fractional ISB (F-ISB) calibration of QZSS and GPS is easier as their magnitudes are receiver-type and firmware-version related. Experiments for the code positioning show that the QZSS and GPS integration with the ISB calibrated by the looked-up values has an obviously smaller 3D distance root mean square, i.e. the root mean square of the radial distances from the true position to the calculated positions. The empirical success rate of the ambiguity fixing in precise positioning is also improved with the looked-up phase F-ISB values. [ABSTRACT FROM AUTHOR]

Space-time image velocimetry (STIV) is a well-established image-based technique for measuring river surface flow from videos or image time series. Because the fundamental measurement mechanism is relatively simple, STIV has been used widely in research and for practical purposes in Japan and other countries. The advantage of STIV over other imaging techniques such as large-scale particle image velocimetry (LSPIV) is its robustness. More specifically, the streamwise velocity component can be efficiently estimated by simply measuring the slope appearing in a space-time image (STI) that represents the advection of surface textures. However, in the course of practical applications cases occur in which STIV yields erroneous results when the measurement conditions at the river site are not satisfactory for accurate measurements, such as when the water surface includes textures other than those directly related to turbulent advection. In this research, surface textures are classified into ten types and image filters based on wavenumber–frequency spectra are developed to improve the quality of the STI so that the texture contains only those features that represents the advection of surface turbulence. The quality of the STI can be improved with the filters and thus further increase the robustness of the measurement technique. [ABSTRACT FROM AUTHOR]

Recently metrological atomic force microscopes (metrological AFMs) have been used for surface roughness measurements. The National Metrology Institute of Japan (NMIJ), AIST, provides a profile surface roughness calibration service using a metrological AFM based on ISO 19606:2017. This international standard requires evaluation of probe-tip diameter D and error in roughness measurements by using a standard plate with needle-shaped spikes before conducting surface roughness measurements. However, the conventional standard plate has several problems: (1) the needle-shaped spikes are too high, (2) the distance between spikes is too long, and (3) the spike curvature radius is not small enough, compared with AFM probe-tip size, which may lead to considerable uncertainty derived from probe-tip error evaluation. This study examined a new type of commercially-available standard plate as a candidate for probe-tip diameter evaluation. It features lower spike height and shorter distance between spikes in order to avoid probe-tip wear caused by repeated scanning. This study demonstrated that the overestimated uncertainty derived from probe-tip error evaluation can be corrected by using the new standard plate. [ABSTRACT FROM AUTHOR]

This study examined the development of a digital pulse analyzer (DPA) used for obtaining the pulse height distribution (PHD), pulse width distribution (PWD), and interval time distribution (ITD) simultaneously by processing output signals from an optical particle counter (OPC). The characterization was performed by testing the response of the DPA as a function of its input frequency and pulse height using dummy signals from a signal generator (model DG1022, Rigol Technologies Inc., People's Republic of China) and actual OPC signals (Model KC-03, Rion Co. Ltd, Japan). Polystyrene latex particles of various sizes yielded by a scanning mobility particle sizer were used during the calibration of the DPA. It was found that the geometric mean of the PHDs was in accordance with Mie theory and could be used for converting pulse height into data which represents the size of particles. Furthermore, by using the PWD and ITD, we could estimate the viewing volume and dead time of the OPC. The DPA could successfully discriminate particles from baseline noise or voltage spikes by applying a novel algorithm to detect pulses based on the pulse area (integral of the voltage–time curve). The results showed that the ranges of particle diameter, viewing volume, and dead time measured by the OPC-DPA system were 0.2–1 µm, (0.78 ± 0.09) mm3, and (45.9 ± 12.6) µs, respectively. The new algorithm can be applied to pulse height analyzers in general, in the measurement of aerosol particles or scintillator-based particle detectors. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the IUTAM Symposium on Vortex Dynamics: Formation, Structure and Function which was held on March 10-14, 2013 in Fukoaka, Japan. Mentioned are the sessions that focused on the development of new mathematical methods and theoretical concepts in vortex dynamics, the theoretical, numerical and experimental issues associated with vortex dynamics and the members of the symposium's International Scientific Committee su8ch as professor D. G. Crowdy.

Following the Fukushima incident, radiation doses from external exposure accounted for the majority of the total doses. Although countermeasures are being implemented, with the aim of reducing radiation exposure, little information is available on the effects of decontamination on individual doses among the residents of radioactively contaminated areas. To evaluate the effectiveness of the decontamination measures in reducing individual doses, and to examine the influence of the timing of decontamination and the district, data were analysed for 18 392 adults and 3 650 children in Minamisoma City, Fukushima, who participated in a voluntary screening programme using individual radiation dosimeters (Glass Badge) between June 2013 and September 2016. The dose reduction rates (DRR) were calculated for one year by comparing the first and last three-month measurement results between areas with and without decontamination. Using a regression approach and Monte Carlo simulation, the dose reduction rate by decontamination eliminating the effect of physical decay (DRRd′) was also estimated as a function of the timing of the decontamination and the dose at the time of starting the decontamination. The annual DRR in areas with decontamination for both adults and children were significantly higher than those in areas without decontamination, depending on the timing of decontamination: 31%–36% for 2013–14 for adults in decontamination areas and 33%–35% for children in decontamination areas, compared to 12%–23% and 13%–23% for adults and children in areas without decontamination, respectively. There was a positive correlation between DRRd′ and individual doses, and DRRd′ was estimated at 30%–40% for adults and children with doses of 3 mSv y−1 in 2013 and 2014. This study demonstrated that decontamination does lower individual doses from external exposure. The higher the dose at the time of starting the decontamination, the greater the dose reduction rate by decontamination, regardless of the timing of the decontamination. Our study confirms that decontamination was useful for high-dose areas in the later phases of the incident. [ABSTRACT FROM AUTHOR]

The effect of pellets on the global magnetohydrodynamic (MHD) dynamics of the Large Helical Device (LHD), which is a large superconducting heliotron in Japan, has been analyzed with the MIPS code. A pellet ablation model based on the neutral gas shielding model has been implemented. Excitation of MHD modes by the three-dimensionally localized pressure perturbation caused by the pellet injection has been observed. The dependence of the MHD-instabilities on the pellet size has been analyzed. [ABSTRACT FROM AUTHOR]

A vibration isolation system called the Type-Bp system used for power recycling mirrors has been developed for KAGRA, the interferometric gravitational-wave observatory in Japan. A suspension of the Type-Bp system passively isolates an optic from seismic vibration using three main pendulum stages equipped with two vertical vibration isolation systems. A compact reaction mass around each of the main stages allows for achieving sufficient damping performance with a simple feedback as well as vibration isolation ratio. Three Type-Bp systems were installed in KAGRA, and were proved to satisfy the requirements on the damping performance, and also on estimated residual displacement of the optics. [ABSTRACT FROM AUTHOR]

At the National Institute of Radiological Sciences (NIRS), more than 8,000 patients have been treated for various tumors with carbon-ion (C-ion) radiotherapy in the past 20 years based on a radiobiologically defined clinical-dose system. Through clinical experience, including extensive dose escalation studies, optimum dose-fractionation protocols have been established for respective tumors, which may be considered as the standards in C-ion radiotherapy. Although the therapeutic appropriateness of the clinical-dose system has been widely demonstrated by clinical results, the system incorporates several oversimplifications such as dose-independent relative biological effectiveness (RBE), empirical nuclear fragmentation model, and use of dose-averaged linear energy transfer to represent the spectrum of particles. We took the opportunity to update the clinical-dose system at the time we started clinical treatment with pencil beam scanning, a new beam delivery method, in 2011. The requirements for the updated system were to correct the oversimplifications made in the original system, while harmonizing with the original system to maintain the established dose-fractionation protocols. In the updated system, the radiation quality of the therapeutic C-ion beam was derived with Monte Carlo simulations, and its biological effectiveness was predicted with a theoretical model. We selected the most used C-ion beam with αr = 0.764 Gy−1 and β = 0.0615 Gy−2 as reference radiation for RBE. The C-equivalent biological dose distribution is designed to allow the prescribed survival of tumor cells of the human salivary gland (HSG) in entire spread-out Bragg peak (SOBP) region, with consideration to the dose dependence of the RBE. This C-equivalent biological dose distribution is scaled to a clinical dose distribution to harmonize with our clinical experiences with C-ion radiotherapy. Treatment plans were made with the original and the updated clinical-dose systems, and both physical and clinical dose distributions were compared with regard to the prescribed dose level, beam energy, and SOBP width. Both systems provided uniform clinical dose distributions within the targets consistent with the prescriptions. The mean physical doses delivered to targets by the updated system agreed with the doses by the original system within ±1.5% for all tested conditions. The updated system reflects the physical and biological characteristics of the therapeutic C-ion beam more accurately than the original system, while at the same time allowing the continued use of the dose-fractionation protocols established with the original system at NIRS. [ABSTRACT FROM AUTHOR]