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The digital economy continues to evolve in Japan and around the world. Big data and personal information have significant economic value and require appropriate legal protection for both information providers and users. Digital platforms, as online intermediaries, occupy a particularly important position in relation to the handling of such information. While digital platforms can greatly benefit society by accumulating and structuring large amounts of data from diverse markets, they can also be prone to the lock-in effect, resulting in monopolies or oligopolies due to network effects. Therefore, digital platforms can have a detrimental effect on individuals and society if they do not operate appropriately. Potential issues include a lack of transparency and fairness of transactions, distribution of infringing content, and the mishandling of data and personal information. Policymakers across the globe recognize these issues, and various regulatory measures have been proposed and implemented. In this paper, we outline how Japan regulates issues related to digital platforms and the digital economy, and highlight some nuances of the Japanese law by comparing it with corresponding European systems.

Liquid scintillation counters (LSCs) have been widely used for low-level tritium measurements. To obtain an accurate tritium activity using a LSC, a quenching correction is required. The quenching ...

Four different Geant4 physics packages, Livermore, Penelope, Emstandard Opt4 and Emstandard Opt1, have been benchmarked against real data in the low-energy region ≤18.6 keV, with regard to β-decay induced X-ray spectrometry (BIXS) applications. The tritium data of two different BIXS experiments have been compared against the calculated detection efficiencies and spectral shapes. All four physics package results showed the main features of the experimentally obtained spectra. The spectral shape was reproduced best by the Penelope physics package. Regarding the detection efficiency, the current data set showed the best agreement with Emstandard Opt1 output, while the maximum deviation of ≤24% was given by the Emstandard Opt4 result.

The particle therapy system simulation framework (PTSIM) is a Geant4 based Monte Carlo simulation software developed for radiation therapy. It has been continuously extending the functions to facilitate advanced researches in medical physics domain. Consequently, the PTSIM is used in many facilities for verification of treatment plans and quality assurances. In the PTSIM, various types of beam devices are provided as software components named “beam-modules”. The geometry is constructed using a class of the beam-module and the detail geometric parameters in the ASCII data format. This strategy contributed that allows the PTSIM users to easily find the beam-module from the categorized types of beam devices and to develop a rapid prototyping of treatment port in the simulation. However, radiation therapy facilities may introduce variants of existing beam-modules, that may require the implementation of a new class for the beam-module in the PTSIM. In order to respond to such requirements without any coding effort, the interface for the Geometry Description Markup Language (GDML) has been introduced in the PTSIM. The GDML is a specialized XML-based language for an application-independent persistent format. Therefore, it can describe a user-defined complex geometry and exchanging the geometry data file among different facilities. In addition, for the purpose of examining complex geometries, a new interface for the ParaView visualization software has been developed. The interface converts the geometry in the PTSIM to the structured points data in the VTK legacy format. This paper reports on the implementations and the usages of GDML and ParaView interfaces in the PTSIM.

The 125I pulse-height spectra via a liquid scintillation counter (LSC) displayed notable variations. The counting efficiencies of higher and lower energy peaks increased and decreased, respectively, with the enhancement of the amount of high atomic numbered elements within the cocktails. This tendency was ascribed to the increasing probability of the interaction of photons with the scintillation cocktail. Moreover, it was noted that the shape of a 125I spectrum strongly depends on the amount of high atomic numbered elements.

Tritium beta-ray induced X-ray spectra in various gas mediums were simulated by Monte Carlo simulation using Geant4 tool kit. The simulated beta-ray induced X-ray spectrum (s-BIX spectrum) was composed of the bremsstrahlung component and characteristics X-rays from constituent elements. The total number of photons in s-BIX spectrum decreased with increasing pressure of medium except argon. In argon medium, the characteristics X-ray of argon was generated by beta particles from tritium decay, and the contribution of Ar-Kα and -Kβ compensated the reduction of bremsstrahlung generated by solid matter with increasing argon pressure. At 0.001 atm of medium pressure, the total counts in s-BIX spectrum was independent from gas medium. Therefore, the gas medium dependence in BIXS at low pressure (less than 0.001 atm) was not serious issue.

The modified sum-peak method can practically estimate radioactivity by using solely the peak and the sum peak count rate. In order to efficiently verify the method in various experimental conditions, a Geant4 based Monte Carlo simulation for a high-purity germanium detector system was applied. The energy spectra in the detector were simulated for a 60Co point source in various source to detector distances. The calculated radioactivity shows good agreement with the number of decays in the simulation.

Non-destructive methods to measure tritium in solids are required for material studies and managements of tritium-contaminated material in the field of fusion research. The beta particle generated by tritium decay cannot usually escape from solids. Namely, the beta particle of tritium decay is difficult to detect in solids. Conversely, the X-rays induced by beta particles in solids escape from the solid, and they can then be detected outside the solid. This is the basis of beta-ray induced X-ray (BIX) spectrometry (BIXS) of tritium. BIXS has potential for quantitative tritium analysis, but it is qualitative rather than quantitative for the solid phase. Because the number and energy of detected X-ray photons depend on the distribution of tritium in the solid, the shape of the BIX spectrum reflects the tritium distribution in the solid. For a quantitative tritium analysis, the tritium distribution in the solid would be evaluated by the shape of the BIX spectrum. In this study, Monte Carlo simulations were employed to determine the change in the BIX spectrum with the tritium depth. The relative intensity of the characteristic X-ray had the information about the tritium distribution and constituent elements of both a solid and an atmosphere. However, the change in the BIX spectrum with the tritium depth depended on the solid material. To consider the BIX spectrum of an unknown solid sample containing tritium, Monte Carlo simulation of the BIX spectrum is indispensable.

One of the methods used for tritium gas analysis is beta-ray induced X-ray spectrometry (BIXS). Gas cell design is important in this method. The structure of the gas cell for BIXS was optimized by Monte Carlo simulation of beta-ray induced X-ray spectra in various window geometries using the Geant4 tool kit (version 10.01.p02). The simulated spectrum from tritium decay fitted the observed one, and the simulation model was used to obtain the cell parameters for BIXS. The optimum thickness of the gold layer on a beryllium window was around 150 nm. This simulation model also considered the relationship between self-absorption by hydrogen gas and the cell length. Self-absorption increased with increasing cell length and the relationship between the sample pressure and cell length was formulated.

We present the first measurement of the Michel parameters η ‾ and ξκ in the radiative leptonic decay of the τ lepton using 703 fb-1 of data collected with the Belle detector at the KEKB e + e − collider. The Michel parameters are measured by an unbinned maximum likelihood fit to the kinematic information of e + e − → τ + τ − → ( π + π 0 ν ‾ ) ( l − ν ν ‾ γ ) ( l = e or μ ) . The preliminary values of the measured Michel parameters are η ‾ = − 2.0 ± 1.5 ± 0.8 and ξ κ = 0.6 ± 0.4 ± 0.2 , where the first error is statistical and the second is systematic.

The luminescence of Eu(DPA)33- induced by beta particles from tritium decay was measured. The solution of Eu3+ was prepared with europium(III) nitrate hexahydrate and was mixed with a DPA (2, 6-pyridinedicarboxylic acid or dipicolinic acid) solution of pH 11 to yield Eu(DPA)33-. The formation of Eu(DPA)33- was confirmed through spectrometry. Tritiated water was added to the prepared solution of Eu(DPA)33-. The luminescence intensity is proportional to the amount of tritium. In this paper we demonstrate the potential of this Eu complex as an inorganic liquid scintillator.

Range verification of therapeutic proton beam is crucial in proton therapy to confirm the irradiation field for ensuring effects and safety of the treatment. The irradiation field reconstruction using prompt gamma-rays generated from excited nuclides by proton beam has being studied for the purpose of precision medicine. A simulation tool based on fundamental physics processes employs an important role to understand intermediate relationship between physics interactions and detected observables, and to optimize a detector system with its analysis method. Previously, we reported on the simulation study about an irradiation field reconstruction by using prompt gamma-rays of whole energy range. In this study, we analyzed the energy spectrum and reconstructed the image of irradiation field by using prompt gamma-rays corresponding to a particular energy peak. The simulation was performed for proton beam with a target placed at the isocenter by using Geant4 based particle therapy system simulation framework. A simple tubular detector was placed around the target, in which the kinetic energy and the detected position of each gamma-ray were recorded. The irradiation field was then reconstructed in the ordered subset expectation maximization method. The reconstructed irradiation fields were compared with the dose distribution in the target. The peak positions of these depth distributions were compared each other and discussed about the range verification of therapeutic proton beam.

To know the appropriate quenching level, the modified integral counting method with various quenched samples (MICM-VQ) was applied for the determination of the disintegration rate of 14C or 35S. The appropriate quenching level for the MICM-VQ was considered by the comparison of the integral scintillation spectrum and the integral beta spectrum. The appropriate quenching level of sample in the MICM-VQ was found. The disintegration rate of sample having appropriate quenching level could be determined by the MICM-VQ.

Geant4 is a Monte Carlo simulation toolkit to simulate interactions of particles with matter. It is widely used in various science field such as high energy physics, nuclear physics, space and medicine. Since Geant4 only provides users with a series of class libraries, users need to develop their own code for target application. It requires user’s expertise in application software developments and deep knowledge of Geant4 classes. In order to minimize such efforts in Geant4 application developments, we have proposed a Geant4 application templet (Galet), that is a skeleton Geant4 application program for primer As one of integrated software based on the Galet, a simulation for liquid scintillation counter system (Galet-LSC) has been developed. It modeled two LSC systems, LSC-5100 and LSC-LB7 manufactured by Hitachi, Ltd. The simulator aims to study characteristics of counting efficiency in various system configurations as well as liquid scintillation properties. In this paper, firstly, the concept and design of Galet are briefly described. Secondly the functions of Galet-LSC is presented. Thirdly, some preliminary results in Galet-LSC are demonstrated.

To achieve the thermonuclear fusion systems, the physical properties of warm dense matter (WDM) are key parameters. In this paper, we review the evaluation of physical properties in WDM by using pulsed-power discharges. To evaluate the thermal conductivity for a divertor wall in magnetic confinement fusion, we investigate a semi-empirical evaluation based on the experimental values for electrical resistivity. The results indicate that, in the region between the interme- diate degeneracy and the non-degeneracy, the evaluated thermal conductivity has an inflection point. To evaluate the electrical resistivity for the fuel target in the inertial confinement fusion, an isochoric heating by using pulsed-power discharge in the pressure vessel has been demonstrated. The results indicate that the electrical resistivity in WDM for gold is 100 μΩ m at 0.1ρ s (ρ s : solid density) of density and the internal energy is 1MJ / kg.

For heavy-ion beam driven inertial confinement fusion, space-charge-dominated beams are studied by a compact experimental device, scaled by electrons instead of heavy ions. In this study, space charge effect is investigated numerically in the compact electron beam simulator. Modeling of the compact beam simulator is studied, and a molecular dynamics simulation, which represent a so-called particle–particle model, is applied to the calculation of particle dynamics in three-dimensional space. A longitudinal-transverse coupling motion is observed in the multi-particle simulation result.

A reconstruction of irradiation field from promptgamma-rays and annihilation gamma-rays is an interest of particle therapy toverify the range of therapeutic beam and confirm the safety of patient. Forthe purpose of precision medicine in proton therapy, an irradiation fieldmonitoring system is under development in the project “Tumor ResponseObservation System for Dose-volume delivers Guided Particle Therapy,TROS-DGPT”. It is developing a hybrid beam online PET and electron trackingCompton Camera (H-BOLP/CCs). In TROS-DGPT project, a simulation tool has animportant role to verify the mutual relationship among dose, radionuclidedistributions inside a patient and reconstructed images from signals inimaging devices. In previous conference, we reported on the development ofimaging device functions in Geant4 based particle therapy system simulationframework (PTSIM). In this paper, we report on results from the study aboutthe irradiation field reconstruction in PTSIM by using prompt gamma-rays.The simulation was performed for proton beam with a target. The target’s material was chosen from polyethylene, water, acrylic and soft tissue. Asimple tubular detector was placed around the target to coincide theisocenter. Scorers were attached to the target and the detector,respectively. The irradiation field was reconstructed in the filtered backprojection (FBP) method. The reconstructed irradiation fields were comparedwith the absorbed energy distribution in the target. The range inreconstructed irradiation field shows some deviation in the peak depth fromthe absorbed energy distribution depending on material of the target.

Liquid scintillation counter (LSC) is one of radioactivity measurement techniques, which is suitable for low level and low energy beta decay radionuclide. LSC counts the number of flushes of scintillation lights by charged particles of decay products. However, the counting rate may be partly lost due to quenching that reduces the light output of the scintillator. Therefore, the compensation of the count rate loss is essential to determine the radioactivity. We previously reported on the study of counting efficiency in double coincidence events of two photomultipliers (PMTs) by using a Geant4 Monte Carlo simulation. In this research, we have newly developed a simulation for LSC-LB7 manufactured by Hitachi, Ltd. that is equipped with three PMTs. The triple and double coincidence ratio (TDCR) method is an interest for quantitative measurement in the field of radionuclide metrology, because the method does not require a series of standard quenched samples for estimating the detection efficiency. For the purpose of studying the counting efficiency and TDCR, the simulation of LSC-LB7 system had been carried out. The liquid scintillation cocktail was assumed to Ultima Gold of PerkinElmer Co. Ltd. The photon yield of scintillation cocktail was adopted from the previous result in LSC-5100, that had been determined in the series of standard quenched sample of C-14. The physics-list took account for all physics processes such as radioactive decay, electromagnetic and optical photon processes. The quantum efficiency and photosensitivity of PMT were also taken into account. H-3, C-14, S-35 and P-32 were generated in scintillation cocktail in a glass vial, respectively. The correlation between TDCR and efficiency was studied by counting events that satisfy the double and triple coincidence in three PMTs. The results show that the correlation is described by a bijective function in the pure beta-decay nuclides.

Takashi Akagi, Tsukasa Aso, Go Iwai, Akinori Kimura, Satoru Kameoka, Se Beyong Lee, Yoshikazu Maeda, Naruhiro Matsufuji, Teiji Nishio, Chihiro Omachi, Seyjoon Park, Takashi Sasaki, Toshiyuki Toshito, Wataru Takase, Tomohiro Yamashita and Yoshiyuki Watase Hyogo Ion Beam Medical Center, 1-2-1, Kouto, Shinghu-cho, Ibo-gun, Hyogo 679-5165, Japan; Nagaoka University of Technology, 1603-1, Nagaoka, Niigata 940-2188, Japan; KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan; Ashikaga Institute of Technology, 268-1, Omae-cho, Ashikaga, Tochigi 326-8558, Japan; National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan; National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeongii-do 411-769, Republic of Korea; Fukui Prefectural Hospital Proton Therapy Center, 2-8-1 Yotsuii, Fukui-shi, Fukui 910-8526, Japan; National Institute for Radiology Science, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan; Nagoya Proton Therapy Center, 1-1-1 Hirate-cho, Kita-ku, Nagoya 462-8508, Japan

In order to explore high energy density physics, we have performed WDM experiment by using several pulsed-power devices. To generate well-defined warm dense state for evaluating electrical conductivity and its properties, we have proposed an isochoric heating of foamed metal by using pulsed-power discharge. The proposed technique yields the electrical conductivity of warm dense matter with a well-defined temperature. To observe the warm dense matter, a pulsed-power generator based on a pulse-forming-network (PFN) was studied toward generating an intense point-spot-like X-ray source from X-pinch technique. From comparison of the designing and the actual inductances of the X-pinch system, the actual inductance of X-pinch system is 3.5 times higher than the designing inductance. To reduce the total inductance of X-pinch system, we will modify the gap switch system such as multi spake gap.

PTSIM is a particle therapy system simulation framework based on Geant4 Monte Carlo simulation toolkit. It was originally developed as a reliable dose calculation tool to verify dose distributions inside patient and dose calculation algorithms in treatment planning systems. Besides such a reliable dose calculation, an irradiation field monitoring is desirable for delivering dose with more ideal distribution. It realizes a concept of a tailor-made proton therapy which performs a specially optimized treatment for each patient. The irradiation field monitoring is performed by reconstructing images by detecting prompt gamma rays and annihilation gamma rays from produced radionuclides by nuclear interactions. The PTSIM has an important role to identify the mutual relationship among dose and radionuclide distributions inside a patient, and reconstructed images from signals in imaging devices. We previously reported on the relevant extending functions in PTSIM such as a pencil beam scanning, a material mapping of CT images and a data output interface for a hospital information system, and proposed the software design for imaging systems. In this paper, we report on the development of imaging device functions in PTSIM according to the software design in the previous work. The implementation provides functional capabilities for a flexible scoring and a detector signal flow. Because of the modulated structure, these functions are handled by users through online commands. For example, a user can choose score quantities and specify a signal flow for emulating a detector response. These capabilities were demonstrated with a simple tubular detector for a flexible scoring function and a signal flow function in PET detectors, respectively. The simulated results show the correlation among dose, radionuclides, and coincide signals in PET detectors.

Liquid scintillation counter (LSC) is the most powerful tool for a quantitative measurement of radioactivity in the field of low level and low energy beta decay radionuclide. LSC counts the number of flushes of scintillation lights generated by the charged particles of decay products, e.g. electrons in C-14 and H-3 decay. However, due to the influence of quench, part of the nuclear decay energy and the generated scintillation photons may escape the detection. Therefore, the compensation of the count rate loss is essential to determine the sample's activity. We previously investigated the performance of Geant4 Monte Carlo simulation for estimating counting efficiencies of C-14 and H-3 samples, respectively. In the simulation, the counting efficiency of each quench sample was estimated by adjusting the scintillation photon yield to reproduce the measured LSC spectrum. Since the conformity assessment of LSC spectra between a simulation and a measurement directly influences the counting efficiency, the assessment protocol need to be verified. In this paper, the conformity of simulated and measured LSC spectra was examined by introducing three feature points, which were defined at 50 %, 20 % and 5 % of the peak counts in the spectrum. The deviation of pulse height at each feature point and the detection efficiency were obtained by varying the scintillation photon yield in simulations. Then, the relations among the pulse height deviations, detection efficiencies and scintillation photon yields were analyzed. As a result, the most feasible feature point was the 5 % of the peak counts in the spectrum for both C-14 and H-3, respectively. By requiring that the simulated spectrum coincides with the measured spectrum at the 5 % feature point, the differences of counting efficiencies between simulations and measurements became within the measurements' uncertainty.

Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made to the toolkit in order to accommodate the needs of these user communities, and to efficiently exploit the growth of computing power made available by advances in technology. The adaptation of Geant4 to multithreading, advances in physics, detector modeling and visualization, extensions to the toolkit, including biasing and reverse Monte Carlo, and tools for physics and release validation are discussed here., Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 835, ISSN:0168-9002, ISSN:1872-9576

The second generation of Belle Silicon Vertex Detector (SVD) has been efficiently operated for more than three years. With increasing beam-induced background, a degradation of the detector performance is expected. To avoid such a difficulty, we are planing a next upgrade, the third generation of the SVD. Currently, its design is almost finalized.

In order to extend the physics reach of the present B factories, a letter of intent for a Super B factory, with a luminosity of 4×1035cm-2s-1, was submitted in 2004. The paper summarizes recent progress in the design and technological solutions for the silicon vertex detector to be operated at the expected high data rate and background condition of a Super B factory.

Particle therapy system simulation framework, PTSIM, is a simulation framework based on Geant4 Monte Carlo simulation. It has been originally developed for particle radiotherapy to simulate dose distribution inside patient. PTSIM has provided a common platform to model proton and ion therapy facilities, allowing users who are not Geant4 experts to accurately and efficiently run Geant4 simulations with the pre-build configurations. Efforts on further development of PTSIM are still under way to include more functionality and improve the performance. In proton therapy, innovations of treatment machines such as a layer-stacking irradiation system and a pencil beam scanning irradiation system have been made for delivering more ideal dose distributions. In order to perform a specially optimized treatment for each patient, e.g. a tailor made proton therapy, there is a strong request to monitor the dose distribution inside patient by measurements in addition to the calculations. Such dose monitoring is performed by reconstructing dose images by detecting prompt and annihilation gamma rays that are produced from radioisotopes in nuclear interactions by primary protons with patient tissues. The PTSIM has an important roll to simulate the secondary isotope productions, its decay, and the signals in imaging devices in addition to delivered dose distributions. The results are used for optimizing detector configurations and mapping the reconstructed dose images to the delivered dose distribution. In this paper, we reports on the implementations of extending functions in PTSIM for medical imaging applications.

The silicon vertex detector (SVD2) of the Belle experiment at KEK (Tsukuba, Japan) is currently close to its limits in terms of the occupancy of the innermost layer and the readout dead time. In order to cope with further increase in luminosity, different levels of upgrades are proposed: small improvements are possible in the short term by tuning the current system at the cost of signal-to-noise and crosstalk. In 2007, the two inner layers of the SVD2 will be replaced by similar detectors with faster readout electronics (SVD2.5) and in the long term, a major upgrade of the full silicon vertex detector (SVD3) is envisaged for the KEK Super B Factory. These upgrade scenarios will be discussed in detail from the hardware point of view along with the options under study.

A major upgrade of the Silicon Vertex Detector (SVD 2.0) of the Belle experiment at the KEKB factory was installed along with new front-end and back-end electronics systems during the summer shutdown period in 2003 to cope with higher particle rates, improve the track resolution and meet the increasing requirements of radiation tolerance. The SVD 2.0 detector modules are read out by VA1TA chips which provide “fast or” (hit) signals that are combined by the back-end FADCTF modules to coarse, but immediate level 0 track trigger signals at rates of several tens of a kHz. Moreover, the digitized detector signals are compared to threshold lookup tables in the FADCTFs to pass on hit information on a single strip basis to the subsequent level 1.5 trigger system, which reduces the rate below the kHz range. Both FADCTF and level 1.5 electronics make use of parallel real-time processing in Field Programmable Gate Arrays (FPGAs), while further data acquisition and event building is done by PC farms running Linux. The new readout system hardware is described and the first results obtained with cosmics are shown.

We present a measurement of the branching fraction for the semileptonic B decay B 0 →D + l − ν , where l− can be either an electron or a muon. We find Γ( B 0 →D + l − ν )=(13.79±0.76±2.51) ns −1 , and the resulting branching fraction B ( B 0 →D + l − ν )=(2.13±0.12±0.39)% , where the first error is statistical and the second systematic. We also investigate the B 0 →D + l − ν form factor and the implications of the result for |Vcb|. From a fit to the differential decay distribution we obtain the rate normalization |Vcb|FD(1)=(4.11±0.44±0.52)×10−2. Using a theoretical calculation of FD(1), the Cabibbo–Kobayashi–Maskawa matrix element |Vcb|=(4.19±0.45±0.53±0.30)×10−2 is obtained, where the last error comes from the theoretical uncertainty of FD(1). The results are based on a data sample of 10.2fb−1 recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e+e− collider.

Liquid scintillation counter (LSC) has been used as a very efficient technique for a quantitative measurement of radioactivity. The LSC has been the most powerful tool in the fields of low level environmental radioactivity monitoring and the detection of low energy beta decay events of radioactivity. In LSC the sample is dissolved in a liquid scintillation cocktail in a sample vial. In order to quantify the nuclear decay in terms of activity, the LSC counts the number of flashes of scintillation lights. However, the sample's count rate varies with the detection efficiency that depends on the energy conversion from the released beta ray energy in nuclear decay to light flashes. Since the sample solution absorbs part of nuclear decay energy and photons of scintillation lights, which is known as quench, the observed count rate becomes less than the expected rate from actual energy. Therefore the compensation of count rate loss is essential to determine the sample's activity. There are many techniques to determine the efficiency, however, it is known that those techniques lead different results especially in low energy beta decay radionuclides such as 3H. In order to investigate the influence of quench phenomena in LSC, we developed a Geant4 based Monte Carlo simulation and validated the beta-ray scintillation spectra in LSC. The simulation takes into account radioactive decay, flashes of scintillation lights, and transportation of optical photons including reflection and refraction characteristics at material boundaries. In this paper, we report on the detail of our simulation and the comparison of beta ray spectra detected in LSC between the simulation and measurements.

In inertial confinement fusion, understanding implosion dynamics of fuel pellet is a key issue to obtain effective nuclear fusion reactions. A foamed metal is considered as structural materials such as a pusher and a radiator.1,2 An energy driver as laser or heavy ion beam irradiates the fuel pellet, and the target material becomes dense plasma through warm dense matter (WDM) regime. Although, the properties in WDM should be clear to design the target pellet.

Physical properties of insulator materials in extreme high pressure and moderate temperature are needed for various fields, such as a silicate for planetary science1, a diamond-like carbon for optimization of implosion process in inertial fusion energy with fast ignition scheme2, and so on.

To understand the behavior of astrophysical phenomena, laboratory scale experiments with well-defined behaviors are required. Collisionless shock phenomena have unclear mechanism such as energy dissipation process and generation of highly energetic particles. To generate the collisionless shock in the laboratory scale experiments, Drake, et al. [1] has considered the required conditions, which depend on the magnetic flux density and the shock velocity. To obtain the collisionless shock, the hypersonic plasma flow generated by a taper-cone-shaped plasma focus device is proposed to evaluate in these shocks.

Geant4 is a large-scale particle physics package that facilitates every aspect of particle transport simulation. This includes, but is not limited to, geometry description, material definition, tracking of particles passing through and interacting with matter, storage of event data, and visualization. As more detailed and complex simulations are required in different application domains, there is much interest in adapting the code for parallel and multi-core architectures. Parallelism can be achieved by tracking many particles at the same time. The complexity in the context of a GPU/CUDA adaptation is the highly serialized nature of the Geant4 package and the presence of large lookup tables that guide the simulation. This work presents G4CU, a CUDA implementation of the core Geant4 algorithm adapted for dose calculations in radiation therapy. For these applications the geometry is a block of voxels and the physics is limited to low energy electromagnetic physics. These features allow efficient tracking of many particles in parallel on the GPU. Experiments with radiotherapy simulations in G4CU demonstrate about 40 times speedups over Geant4.

Particle therapy system simulation framework, PTSIM, is a simulation framework based on Geant4 Monte Carlo simulation. It has been developed in the project, “Development of simulation framework for advanced radiotherapy”, funded by the Japan Science and Technology Agency (JST) in the program of Core Research for Evolutional Research and Technology (CREST), from 2003 to 2010. The PTSIM has provided a common platform to model proton and ion therapy facilities, allowing users who are not Geant4 experts to accurately and efficiently run Geant4 simulations with the pre-build configurations. Efforts on further development of PTSIM are still under way to include more functionality and improve the performance. The PTSIM has been upgraded with the extensions in the DICOM-RT interface to coordinate with hospital information system, the Web interface with universal grid environment, etc. In this paper, we report on our activities about these updates and plan for extending the PTSIM functionality with new requirements from users.