Data Analysis of Cosmic-ray Nuclei Observed by The Antarctic Balloon Flight

本研究的目的是通过长时间气球飞行观测宇宙线核，了解银河宇宙线的加速和传播机制。为此，我们正在进行由芝加哥大学主持的TRACER计划，并在南极洲进行了长时间的气球飞行，观测到了各种宇宙线核。TRACER实验的仪器包括测量电离能损失的塑料散射器、测量Cherenkov光的Cherenkov计数器、测量电离和粒子坐标的正比管阵列和跃迁辐射探测器。数据分析程序如下。首先，利用1,600个比例管的信号重建入射粒子的轨迹。接下来， ...更多信息 通过闪烁体和切伦科夫计数器的信号组合来识别每个粒子的电荷。另一方面，能量的测量1）切伦科夫信号的能量区域周围的1GeV，2）相对论上升的电离损失的能量区域从几倍10 GeV到几倍100 GeV，3）的跃迁辐射信号的能量超过400 GeV。结果表明，在10^ eV ~ 10^ eV范围内，重宇宙线核的能谱具有较高的统计特性<14><15>。将这些结果与银河宇宙线加速和传播的一些模型进行比较，它们与我们观察到的所有物种在超新星遗迹处的传统扩散激波加速模型是一致的。对于传播机制，我们得到了一些模型参数，例如，源处能谱的功率指数为-2.3，源区周围的剩余路径长度为0.1 g/cm ^2。TRACER小组于2006年7月从瑞典到加拿大进行了另一次为期四天半的气球飞行，使用改进的仪器进行了宇宙线观测。我们对这次观测进行了初步的数据分析，证实了在以前的观测中没有观测到的硼核被探测到，没有任何偏差。这是检测器的动态范围的改进的成就。它使我们有可能获得硼与碳的相对丰度，这是了解银河宇宙线传播机制的重要数据。计划在不久的将来再用这种仪器进行一次长时间的气球飞行。少

The aim of this study is the understanding of the acceleration and the propagation mechanisms of galactic cosmic-rays with observing the cosmic-ray nuclei by means of long duration balloon flights. For this purpose, we are working on the TRACER project which is mainly performed by the University of Chicago, and the various kinds of cosmic-ray nuclei have been observed by the long duration balloon flight in Antarctica. Finally we obtained the absolute flux and the energy spectra for many elements of the cosmic-ray heavy nucleus.The instrument for the TRACER experiment consists of plastic scintillators for measurement of ionization energy loss, a Cherenkov counter for Cherenkov lights, proportional tube arrays for the measurement of the ionization and the coordinates for particles and the transition radiation detectors. The procedure of data analysis is as follows. First, the tracks of incident particles are reconstructed with use of the signals from 1,600 of proportional tubes. Next, th … More e charges for each particle are identified by the combination of the signals of scintillator and Cherenkov counter. On the other hand, the energies are measured 1)by Cherenkov signal for the energy region around 1GeV, 2)by relativistic rising of the ionization loss for the energy region from several times 10 GeV to several times 100 GeV, 3)by transition radiation signal for the energies more than 400GeV. As results, the energy spectra for heavy cosmic-ray nuclei are obtained with high statistics for the region from 10^<14>eV〜 10^<15>eV. Comparing these results to some models for the acceleration and the propagation of Galactic cosmic-rays, they are consistent with the conventional diffusive shock acceleration model at supernovae remnants for all species we observed. For the propagation mechanisms, we got some model parameters, -2.3 of power index of the energy spectrum at the source and 0.1 g/cm^2 of the residual path length around source region, for example.The TRACER group performed another balloon flight for observation of cosmic-rays during four and half days with use of improved instrument from Sweden to Canada in July 2006. We made a preliminary data analysis for this observation and confirmed that boron nuclei, which were not observed in previous observation, have been detected without any biases. This is an accomplishment of the improvement of the dynamic range of the detector. It made us possible to obtaine the relative abundance of boron to carbon which is very important data for understanding the propagation mechanisms of the Galactic cosmic-rays. One more long duration balloon flight with this instrument is scheduled in near future. Less