Development of apthoton sensor with ultra high sensitivity.

研制了一种由光电阴极和多像素雪崩二极管（MP-AD）组成的混合光电探测器。我们以前的研究表明，其固有的高分辨率光子计数的潜力，可以进一步提高通过减少在MP-AD的入口处的死层中的电荷损失的波动。在这项研究中，我们成功地证明了新开发的HPD的改进，其封装的MP-AD具有比以前更薄的死层。结果表明，新的HPD具有更好的能量分辨率，可以更清晰地计数多达9个光电子。进一步提高的HPD的光阴极灵敏度也进行了研究。

A hybrid photo-detector (HPD) consisting of a photocathode and a multi-pixel avalanche diode (MP-AD) has been developed. Our previous studies showed that its inherent potential for high resolution photon counting could be further enhanced by reducing fluctuations in charge loss in the dead layer at the entrance of the MP-AD. In this study, we successfully demonstrate the improvement with the newly developed HPD whose encapsulated MP-AD has a thinner dead layer than before. It is demonstrated that the new HPD has much better energy resolution, which enables clearer counting up to nine photoelectrons. Further enhancement of the photocathode sensitivity of the HPD is also investigated.