A5022281989- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- Particle accelerators and beam dynamics
- Nuclear Physics and Applications
- Advanced X-ray Imaging Techniques
- Gyrotron and Vacuum Electronics Research
- Radiation Therapy and Dosimetry
- Laser Design and Applications
- Radiation Detection and Scintillator Technologies
- Non-Destructive Testing Techniques
- Advanced Radiotherapy Techniques
- Advanced X-ray and CT Imaging
- Pulsed Power Technology Applications
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
- Particle Detector Development and Performance
- Photocathodes and Microchannel Plates
- Ultrasonics and Acoustic Wave Propagation
- Welding Techniques and Residual Stresses
- Magnetic confinement fusion research
- Radiation Effects and Dosimetry
- Geophysical Methods and Applications
- Physics of Superconductivity and Magnetism
The University of Tokyo
2014-2023
Japan Atomic Energy Agency
2022
Science Council of Japan
2020
National University of Singapore
2019
Ghent University Hospital
2019
Tokai University
2003-2018
Tokyo University of Technology
2011-2016
Bunkyo University
1997-2014
National Institute of Advanced Industrial Science and Technology
2014
Special Olympics
2013
A strong effect of radiation damping on the interaction an ultraintense laser pulse with overdense plasma slab is found and studied via a relativistic particle-in-cell simulation including ionization. Hot electrons generated by irradiation radiance I lambda(2)>10(22) W microm(2)/cm(2) duration 20 fs can convert more than 35% energy to radiation. This incoherent x-ray emission lasts for only be intense. The efficiency shown increase nonlinearly intensity. Similar cyclotron radiation, may...
With detailed experimental studies and hydrodynamics particle-in-cell simulations we investigate the role of prepulse in laser proton acceleration. The or pedestal (amplified spontaneous emission) can completely evaporate irradiated region a sufficiently thin foil; therefore, main part pulse interacts with an underdense plasma. multiparametric demonstrate that generates quasistatic magnetic field, which its turn produces long-lived charge separation electrostatic accelerating ions.
One of the restrictions in potential use gold markers for medical imaging/tracking harder tumors is its size. We propose to nanoparticles which, due small size, can be administered conveniently via intravenous injection. factors that determine clinical utility ability enter cells. In this report, stability mixed with different media was determined by UV-vis spectroscopy. Gold nanoparticle size confirmed TEM. Intracellular uptake using sizes, incubation times and concentrations were analyzed...
This paper describes a new method for the magnetic force analysis of high T/sub c/ superconductor based on flux flow and creep model. The introduction artificial conductivity, which is used in conventional method, not needed. CPU time requirement calculations considerably lower than that case method. Thereby vibration levitated permanent magnet was numerically analyzed by taking into account creep.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We use a one-shot measurement technique to study effects of laser prepulses on the electron wakefield acceleration driven by relativistically intense pulses ($\ensuremath{\lambda}=790\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, $11\phantom{\rule{0.3em}{0ex}}\mathrm{TW}$, $37\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$) in dense helium gas jets. A quasimonoenergetic bunch with an energy peak $\ensuremath{\sim}11.5\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ [$\ensuremath{\Delta}E∕E\ensuremath{\sim}10%$...
Poly(ADP-ribose) polymerase (PARP) inhibitors have been proven to represent superior clinical agents targeting DNA repair mechanisms in cancer therapy. We investigated PARP inhibitory effects of the natural and synthetic flavonoids (quercetin, rutin, monoglucosyl rutin maltooligosyl rutin) tested lethality BRCA2 mutated cells. In vitro ELISA assay suggested that on activity, but glucosyl modifications reduced effect. Cytotoxicity tests Chinese hamster cells defective gene (V-C8) its parental...
This paper studies the ultrasonic detection and evaluation of internal volume defects in metals using laser generation electromagnetic acoustic transducer (EMAT) detection. A finite element model is developed to simulate interaction laser-generated waves with defect material. Not only have directly scattered shear been observed, but also mode-converted creeping on surface. noncontact laser-EMAT testing experimental system was successfully applied validate observed phenomena simulation...
Significant enhancement of emittance and an increase the total charge femtosecond electron beams produced by a 12 TW, 40 fs laser pulse, tightly focused in He gas jet, are observed after applying static magnetic field, B> or =0.2 T, directed along axis pulse propagation. The effect appears when plasma prepulse becomes magnetized vicinity focus point: Larmor frequency exceeds collisional frequency, while periphery remains unmagnetized. entailed change shape suppresses diffraction main that...
In order to effectively and appropriately manage external radiation doses in the affected areas of Fukushima, it is important identify when, where how much exposure occurred. It also necessary quantitatively measure air dose rates for different activity patterns individuals living working Japanese-style buildings. The authors used a new personal dosemeter (D-shuttle) along with global positioning system geographical information relate rate rate. Hourly individual obtained by D-shuttle can...
Spatial and energy distributions of energetic electrons produced by an ultrashort, intense laser pulse with a short focal length optical system (Ti:sapphire, 12 TW, 50 fs, $\ensuremath{\lambda}=790\mathrm{nm},$ $f/3.5)$ in He gas jet are measured. They shown to depend strongly on the contrast ratio shape prepulse. The wave breaking plasma waves at front shock formed proper prepulse is found make narrow-cone $(0.1\ensuremath{\pi}\mathrm{mm}$ mrad) electron injection. These further accelerated...
A new three-dimensional (3-D) finite element scheme for eddy-current nondestructive evaluation (NDE) problems is described that calculates directly the perturbation of electromagnetic field due to defects in metallic specimens. The computational costs such are usually very high using available schemes, and supposed lower these costs. basic concept, direct calculation distortion flaw, provided rather general defects, but detailed discussed zero-conductivity flaws. source terms formulation...
High linear energy transfer (LET) radiation such as carbon ion particles is successfully used for treatment of solid tumors. The reason why high LET accomplishes greater tumor-killing than X-rays still not completely understood. One factor would be the clustered or complex-type DNA damages. We previously reported that complex double-strand breaks produced by enhanced end resection, and this could lead to higher kinase activity ATR protein recruited RPA-coated single-stranded DNA. Although...
High‐linear energy transfer ( LET ) heavy ions have been increasingly employed as a useful alternative to conventional photon radiotherapy. As recent studies suggested that high radiation mainly affects the nonhomologous end‐joining NHEJ pathway of DNA double strand break DSB repair, we further investigated this concept by evaluating combined effect an inhibitor NU 7441) at non‐toxic concentration and carbon ions. 7441‐treated non‐small cell lung cancer NSCLC A549 H1299 cells were irradiated...
Acceleration of ions in a solitary wave produced by shock-wave decay plasma slab irradiated an intense picosecond laser pulse is studied via particle-in-cell simulation. Instead exponential distribution as known mechanisms ion acceleration from the target surface, these accelerated forwardly form bunch with relatively low energy spread. The shown to be moving over expanding plasma; its velocity can exceed maximal forward rear side target.
Density effects on the dynamics of a cavity produced in wake an ultraintense (a0=eE/mcω≫1) and short (ωplτ/π&lt;1) laser pulse duration accelerated electrons are studied via two-dimensional particle-in-cell simulation. Formation nonbreaking is crucial part relativistic self-injection plasma from front their further acceleration leading to beam-quality femtosecond bunch. This appears uniform when group velocity becomes smaller than maximal electron ponderomotive bias, Φ=mc2a02/2. However...
Hundred-mega-electron-volt electron beams with quasi-monoenergetic distribution, and a transverse geometrical emittance as small ∼0.02 π mm mrad are generated by low power (7 TW, 45 fs) laser pulses tightly focused in helium gas jets an external static magnetic field, B∼1 T. Generation of monoenergetic strongly correlates appearance straight, at least 2 length plasma channel short time before the main pulse energy copropagating picosecond pedestal (PPP). For moderate PPP, multiple or staged...
Abstract Background Chordoma, a rare cancer, is usually treated with surgery and/or radiation. However, very limited characterizations of chordoma cells are available due to minimal availability (only two lines validated by now) and the extremely long doubling time. In order overcome this situation, we successfully derived cell line shorter time from first U-CH1 obtained invaluable biological data. Method After isolating subpopulation short (U-CH1-N), growth, cycle distribution, DNA content,...
A phased array laser ultrasound generation system by using fiber optic delivery and a custom-designed focusing objective lens has been developed for crack inspection. The enhancement of tip diffraction is simulated with finite element method validated experiment. non-contact non-destructive measurement inner-surface cracks time-of-flight fiber-phased electromagnetic acoustic transducer detection studied.
Neutrons are used as a probe on large scale in variety of scattering types, e.g. diffraction and reflection, for the study structure dynamics materials not only science,...
In the present study, role of monoglucosyl‑rutin as a potential radioprotector was investigated using mammalian cell culture models. Cell survival and DNA damage were assessed colony formation, sister chromatid exchange γH2AX assays. It demonstrated that able to increase when exposed ionizing radiation, possibly by decreasing amount base experienced cell. However, study also that, despite exhibiting radioprotective effects at low doses, high doses led decrease in plating efficiency an...