Research of Nuclear Excitation by Electron Transition on ^<189>Os

在2001财年，我们开发了一种内部转换电子探测器与净硅雪崩光电二极管（si - apd）。探测器有两个单片Si-APD阵列，直径为3毫米，安装在真空室中。我们使用8.4 kev x射线在光子工厂的光束线BL-14A上对探测器进行了测试。结果表明，由于探测区域内的增益位置差异较大，Si-APD阵列的能量分辨率较普通器件差。虽然我们不能使用新的si - apd，但我们试图观察；在^<193>Ir上的电子跃迁（NEET）核激发，正如我们计划的那样，探测器在真空室中有一个Si-APD。实验是在SPring-8的BL09XU上完成的。我们成功地观测到了NEET，它的概率小于^<197>Au的十分之一。我们的NEET概率结果为（2.8±0.2）×10^<-9>，而最近的计算结果为2.0×10^<-9>。结果之间的差异将被讨论。在2002财年，Si-APD阵列被改进并在BL-14A上再次测试。在探测器中安装阵列后，能量分辨率有所提高。然而，由于Si-APD改进的延迟以及我们在SPring-8实验期间加速器出现问题，我们没有机会在^<189> o上执行NEET实验。2002财年之后，在2003年4月，我们在SPring-8的BL09XU上尝试观测了^ 889 bb100s上的NEET。在实验中，我们使用了另一种Si-APD，因为Si-APD阵列的信噪比小于我们的预期。在k壳层电离中，仍未观测到^<189>Os上的NEET。将继续改进检测器以获得更好的信噪比。

In FY2001, we developed an internal-conversion electron detector with nety silicon avalanche photodiodes (Si-APDs). The detector had two monolithic Si-APD arrays ofthitee pixels (3 mm in diameter), installed in a vacuum chamber. We tested the detector at beamline BL-14A of the Photon Factory using 8.4-keV x-rays. The results had a problem that the energy resolution ofthe Si-APD array was worse than that of a normal device due to a large difference of gains cn position in the detection area. Though we could not use the new Si-APDs, we tried to observe; the nuclear excitation by electrontransition (NEET) on ^<193>Ir, as we scheduled in our plan, with the detector that had one Si-APD in the vacuum chamber. The experiment was done at BL09XU of the SPring-8. We successfully observed NEET, of which probability was less than one tenth otfthat on ^<197>Au. Ourresult of the NEET probability was (2.8±0.2)×10^<-9>, while a recent calculation presented a value of 2.0×10^<-9>. The difference between the results will be discussed.In FY2002, the Si-APD array was improved and tested again at BL-14A. The energy resolution became better and the arrays were installed in the detector. However, we did not have a chance for executing an experiment for NEET on ^<189>Os due to a delay of improving the Si-APD and due to atrouble in the accelerator within a period of our experiment at the SPring-8. After FY2002, in April 2003, we have tried to observe NEET on ^<I89>Os at BL09XU of the SPring-8. In the experiment, we used another Si-APDs because a signal-to-noise ratio of the Si-APD array was smaller than that we expected. With the detector, NEET on ^<189>Os was still not observed in the K-shell ionization. The improvement in the detector for a better signal-to-noise ratio will be continued.