Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ishikawa, Norito; Takegahara, Keisuke*
Nuclear Instruments and Methods in Physics Research B, 272, p.227 - 230, 2012/02
Times Cited Count:13 Percentile:67.57(Instruments & Instrumentation)In order to characterize a possible modification due to high-density electronic excitation, thin films of CeO have been irradiated with 10-MeV Ni and 120-MeV Xe ions, both having the same nuclear stopping powers, while having different electronic stopping powers. The comparison of the fluence dependence of X-ray diffraction (XRD) peaks suggests that the defect production cross section for 120-MeV Xe is nearly one order of magnitude higher than that for 10-MeV Ni. The comparative study demonstrates the prominent damage observed for 120-MeV Xe irradiation is due to high electronic energy deposition.
Ishikawa, Norito; Sonoda, Takeshi*; Okamoto, Yoshihiro; Sawabe, Takashi*; Takegahara, Keisuke; Kosugi, Shinya*; Iwase, Akihiro*
Journal of Nuclear Materials, 419(1-3), p.392 - 396, 2011/12
Times Cited Count:11 Percentile:62.35(Materials Science, Multidisciplinary)In order to characterize the radiation damage due to ion-track formation in UO, polycrystalline samples have been irradiated with 210-MeV Xe ions, and measured with XRD (X-ray diffraction) technique using Cu X-ray. We have also tried EXAFS (extended X-ray absorption fine structure) measurement using X-ray near U L
-edge. The results show that XRD technique detects damage at relatively low fluence of 10
ions/m
and higher, while the irradiation-induced change of EXAFS spectra is not observed even at highest fluence of 10
ions/m
. The damage detection may be critically influenced by the depth profile of X-ray penetration.
Kumada, Takayuki; Noda, Yohei; Ishikawa, Norito; Takegahara, Keisuke*
no journal, ,
We carried out dynamic nuclear polarization study of electron- and ion-beam irradiated polyethylene. We found that grow and decay rates of polarization linearly increased proportional to the concentration of alkyl radicals, whereas they quadratically increased with TEMPO concentration in TEMPO-doped polystylene. This result suggests that pairs of alkyl radicals are produced by the radiolysis. The pair distance is estimated to be less than 1 nm.
Takegahara, Keisuke; Ishikawa, Norito
no journal, ,
The correlation between electronic stopping power and ion-track size is studied. The results indicate that the X-ray diffraction method sensitively detect lattice distortion around ion-tracks which is not detected by transmission electron microscope.
Takegahara, Keisuke; Ishikawa, Norito
no journal, ,
Ion irradiation damage in oxide ceramics has been evaluated by two different methods. Two methods give different damage size, but these results can be interpreted by a consistent analytical model.
Ishikawa, Norito; Takegahara, Keisuke
no journal, ,
In this study, irradiation damage is investigated in terms of nuclear energy loss and electronic energy loss.