Relation between biomolecular dissociation and energy of secondary electrons generated in liquid water by fast heavy ions

Tsuchida, Hidetsugu*; Kai, Takeshi; Kitajima, Kensei*; Matsuya, Yusuke; Majima, Takuya*; Saito, Manabu*

European Physical Journal D, 74(10), p.212_1 - 212_7, 2020/10

https://doi.org/10.1140/epjd/e2020-10172-x

Fundamental study of interaction between biomolecules and heavy ions in water is very important to predict an initial stage of radiation biological effects. A heavy ion irradiation experiment into droplet target assumed as a biological system in a vacuum was performed to measure production yields of cations and anions for glycine, which was ejected from the droplet target to the vacuum. However, the production mechanisms have been unknown. The PHITS code adapting ion track structure mode was used to analyze the production mechanisms from the dose evaluation at the surface between the vacuum and the water. It is found that induction yields of ionization and excitation, and dissociative electron attachment involved in the secondary electrons were correlated with the production yields of cations and anions of the glycine. The results provide us newly scientific insights to predict an initial stage of radiation biological effects.

Brightness enhancement of a linac-based intense positron beam for total-reflection high-energy positron diffraction (TRHEPD)

Maekawa, Masaki; Wada, Ken*; Fukaya, Yuki; Kawasuso, Atsuo; Mochizuki, Izumi*; Shidara, Tetsuo*; Hyodo, Toshio*

European Physical Journal D, 68(6), p.165_1 - 165_6, 2014/06

https://doi.org/10.1140/epjd/e2014-40802-7

Control of laser-accelerated proton beams by modifying the target density with ASE

Yogo, Akifumi; Kiriyama, Hiromitsu; Mori, Michiaki; Esirkepov, T. Z.; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Nagatomo, Hideo*; et al.

European Physical Journal D, 55(2), p.421 - 425, 2009/11

https://doi.org/10.1140/epjd/e2009-00045-5

We demonstrate the laser-ion acceleration from a near-critical density plasma, when amplified spontaneous emission (ASE) was used to convert a solid foil target into the lower-density target. In this work, a direct comparison is made by changing the ASE intensity by factor 3 in order to investigate the target density-dependency of the laser-ion acceleration. The beam direction of high-energy component is successfully controlled by modifying the target density. The near-critical density plasma can be a favorable target to control the beam direction to be dependent on its energy.

Prospect for extreme field science

Tajima, Toshiki

European Physical Journal D, 55(2), p.519 - 529, 2009/11

https://doi.org/10.1140/epjd/e2009-00107-8

The kind of laser Extreme Light Infrastructure (ELI) provides will usher in a class of experiments we have only dreamed of for years. The characteristics that ELI brings in include: the highest intensity ever, large fluence, and relatively high repetition rate. A personal view of the author on the prospect of harnessing this unprecedented opportunity for advancing science of extreme fields is presented. The first characteristic of ELI, its intensity, will allow us to access, as many have stressed already, extreme fields that hover around the Schwinger field or at the very least the neighboring fields in which vacuum begins to behave as a nonlinear medium. In this sense, we are seriously probing the "material" property of vacuum and thus the property that theory of relativity itself described and will entail. We will probe both special theory and general theory of relativity in regimes that have been never tested so far. We may see a glimpse into the reach of relativity or even its breakdown in some extreme regimes. We will learn Einstein and may even go beyond Einstein, if our journey is led. Laser-driven acceleration both by the laser field itself and by the wakefield that is triggered in a plasma is huge. Energies, if not luminosity, we can access, may be unprecedented going far beyond TeV.

Stability of a plasma foil in the radiation pressure dominated regime

Pegoraro, F.*; Bulanov, S. V.

European Physical Journal D, 55(2), p.399 - 405, 2009/11

https://doi.org/10.1140/epjd/e2009-00063-3

Startup of superheavy element chemistry at RIKEN

Haba, Hiromitsu*; Akiyama, Takahiro*; Kaji, Daiya*; Kikunaga, Hidetoshi*; Kuribayashi, Takahiro*; Morimoto, Koji*; Morita, Kosuke*; Oe, Kazuhiro*; Sato, Nozomi*; Shinohara, Atsushi*; et al.

European Physical Journal D, 45(1), p.81 - 86, 2007/10

https://doi.org/10.1140/epjd/e2007-00135-4

A review is given on the startup of the superheavy element (SHE) chemistry at RIKEN. A gas-jet transport system for the SHE chemistry has been coupled to the gas-filled recoil ion separator GARIS at the RIKEN Linear Accelerator. The performance of the system was appraised using Fr and Fm produced in the Tm(Ar,3)Fr and Pb(Ar,3)Fm reactions, respectively. The particles of Fr and Fm separated with GARIS and transported by the gas-jet were identified with a rotating wheel system for spectrometry under desired low background condition. The high gas-jet efficiencies over 80% were independent of the beam intensities up to 2 particle A. A gas-jet coupled target system for the production of SHEs was also installed on the beam line of the RIKEN K70 AVF cyclotron. The gas-jet transport of No and Rf produced in the U(Ne,5)No and Cm(O,5)Rf reactions, respectively, was conducted for the future chemical studies of Sg via the Cm(Ne, 5)Sg reaction.

Effect of ion irradiation on C thin films

Narumi, Kazumasa; Xu, Y.; Miyashita, Kiyoshi*; Naramoto, Hiroshi

European Physical Journal D, 24(1-3), p.385 - 388, 2003/06

https://doi.org/10.1140/epjd/e2003-00150-5

The structural changes have been investigated in C thin films irradiated with 7-MeV C ions using Raman spectroscopy. First, irradiated C thin films show resistance to photopolymerization. The extent of the resistance increases with increasing fluence of ion irradiation. The effect is qualitatively explained by the fact that the photochemical reaction is suppressed by destructive collisions of the C molecules with the energetic ions followed by lattice damage. Secondly, no intermediate fragments of a C molecule generated by ion impact are observed, , each C molecule completely decomposes into its constituent atoms in a single catastrophic event upon energetic-ion impact. An effective cross section for decomposition of the C molecule is derived from dependence of the peak-intensity ratio of (2) as = 5.110 cm.

Zeeman effect of atomic uranium in the high lying odd levels measured by laser induced fluorescence spectroscopy

Oba, Masaki; Akaoka, Katsuaki; Miyabe, Masabumi; Wakaida, Ikuo

European Physical Journal D, 10(3), p.349 - 352, 2000/06

https://doi.org/10.1007/s100530050558

no abstracts in English