| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
In FY1997, an electron analyzer for time-spectroscopy was designed and assembled. The analyzer was cylindrical-mirror type. Next year, some avalanche photodiodes (APDs) were tested at beamline BL14A of the Photon Factory. One device that had a thin SiOィイD22ィエD2 layer was chosen as the electron detector for the analyzer. Until the end of FY1998, we could not report the results of this project due to the delay of improving the electron analyzer and due to no chances of experiments at Spring-8. However, in April and May of 1999, we were able to execute the experiments under a new project of the SPring-8. In the experiments, we successfully observed the nuclear excitation by electron transition (NEET) in 197Au. The internal-conversion electrons emitted from excited nuclei were directly detected by the APD device without the electron analyzer. This method was adopted for taking a larger efficiency of the conversion electrons. The observed NEET probability was close to the calculated value (E.V.Tkalya, JETP 78,239(1994)), though smaller by three orders of magnitude than the previous experimental value (H.Fujioka et al., Z.Phys. A315, 121 (1984)).
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