| Budget Amount *help |
¥20,670,000 (Direct Cost: ¥15,900,000、Indirect Cost: ¥4,770,000)
Fiscal Year 2013: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2012: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2011: ¥13,260,000 (Direct Cost: ¥10,200,000、Indirect Cost: ¥3,060,000)
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| Research Abstract |
We investigate X-ray auto correlator to determine the duration of femtosecond pulses from X-ray free-electron lasers. We successfully observe double core-hole creation in krypton and direct two-photon absorption in germanium, which are indispensable two-photon processes for the auto correlator. We estimate the pulse duration to be 2.5 fs by analyzing the X-ray fluorescence spectrum from the double core-hole state. We find a competition between K-shell two-photon absorption and L-shell one-photon absorption. We analyze the pulse-energy dependence of two-photon absorption including the competition effect. Finally, we successfully reproduce the observed pulse-energy dependence, and determine the cross section of two-photon absorption. The competition determines the highest intensity for the auto correlator with two-photon absorption.
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