basic development for next generation hard X-ray polarimeter using capillary phenomena

在高能天体物理学领域，需要能够准确探测硬x射线区的偏振度的偏振计。但是，目前还没有这样的偏振计，因为研制起来非常困难。所以我们正在开发一种硬x射线康普顿散射型偏振仪能够拍摄恒星物体的图像。利用毛细现象将液体闪烁体吸收到毛细板上制成散射体。由于散射体采用带液体闪烁体的毛细管板，原则上可以实现对散射位置的检测，精度为0.01mm。首先，我们建立了将液体闪烁体吸收到毛细管板中的方法。因此，我们成功地利用毛细管现象将几种类型的液体闪烁体吸收到毛细管直径为0.006 mm的毛细管板中。此外，我们还建立了密封毛细管板内液体闪烁体的技术。为了验证这一操作，我们将热中子注入毛细管板，并在光电倍增管上安装了用于中子的液体闪烁体。由于注入中子所发出的光比注入硬x射线所发出的光要多，所以适用于基本操作的检查。我们准备了两种毛细管板，进行了三种实验。一个毛细管板装有用于中子捕获的液体闪烁体，而另一个毛细管板不装有液体闪烁体。我们称前者为毛细板A，后者为毛细板B。实验一，向毛细管板A注入热中子。实验二，向毛细管板b注入热中子。实验三，在不注入中子的情况下，测量毛细管板A的背景。作为结果，我们确认只有在实验一中才检测到重要信号。

In the fields of high energy astrophysics, the polarimeter is required that can detect the polarization at accuracy in the hard X-ray region. However, there are not such polarimeters because the development is very difficult. So we are developing a hard X-ray Compton scattering type polarimeter capable of taking image of stellar objects. The scatterer is made by absorbing liquid scintillator to a capillary plate with capillary phenomena. As the capillary plate with liquid scintillator would be used for the scatterer, it is in principle possible to detect the scattering position with the accuracy of 0.01mm.At first, we established how to absorb the liquid scintillator into the capillary plate. So we succeeded in absorbing several types of liquid scintillator into the capillary plate with the capillary diameter of 0.006 mm by capillary phenomena. Moreover, we also established the technique to seal the liquid scintillator in the capillary plate. To test the operation, we injected thermal neutrons into the capillary plate with the liquid scintillator for neutrons mounted on a photomultiplier. Because the emitted lights from the liquid scintillator due to neutron injection is more than those due to hard X-ray injection, it is suitable for the check of the basic operation. We prepared for two kind of capillary plates and carried out three kinds of experiments. One capillary plate contains the liquid scintillator for neutron capture and the other one does not contain liquid santillator. We call the former one as capillary plate A and the latter one as capillary plate B, respectively. For experiment I, thermal neutrons were injected to the capillary plate A. For experiment II, thermal neutrons were injected to the capillary plate B. For experiment III, the background for the capillary plate A was measured without neutron injection. As the results, we confirmed that the significant signals were detected only for the experiment I.