1月12日大阪大学羽原英明副教授学术报告《Measurements of high energy density electrons via observation of Cherenkov radiation》 [2010-01-11]

　　大阪大学羽原英明副教授即将来访，定于12日14:30在329房间举行学术报告。报告的题目和摘要如下

Title："Measurements of high energy density electrons via observation of Cherenkov radiation".

Abstract：

  Direct measurement of extremely high energy density electrons created  in ultra-intense laser plasma interactions is crucial issue for Fast Ignition. Cherenkov radiation is studied to obtain the energy distribution of electrons because the emission angle depends on the 
electron energy. However in the previous studies [F. Brandl et al.Europhys. Lett. 61, 632 (2003); M. Manclossi et al. Phys. Rev. Lett.96, 125002 (2006)], the experimental configurations using a planer target raised issues of spatially overlapping among the light from the different energy electrons as well as the other emissions such as transition radiation. We developed a novel prism shaped target in which Cherenkov light emitted from different energy electrons are spatially separated, realizing an absolute measurement of the energy spectrum by counting the light intensities in each observed position. 

   In the experiment we observed a clear expected horseshoe pattern indicating a portion of Cherenkov ring image. In addition, we found that many parts of electrons are considered to propagate along laser axis from the blur of the outer edge of the pattern. The calibrated energy spectrum agrees extremely well with a PIC calculation.

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