CRaTER Galactic Cosmic Ray (GCR) Linear Energy Transfer (LET) Spectra

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) has been in orbit around the Moon aboard NASA's Lunar Reconnaissance Orbiter (LRO) since 2009. Its primary observations have been of the slowly-varying flux of galactic cosmic rays (GCRs) arriving from interplanetary space, which are modulated by solar activity. This dataset presents the Linear Energy Transfer (LET) spectra of the cosmic rays, as measured when the sensor was facing straight up away from the lunar surface and during periods when solar energetic particle activity is quiet, from the spacecraft's arrival at the Moon until the present day. These LET spectra quantify the energy deposit (radiation dose) behind 9.9 g/cm^2 of shielding, mostly consisting of Tissue-Equivalent Plastic (TEP). This is an ongoing dataset, and will be updated with another measurement of the LET spectrum every six months. Plots of the variations of these measurements over the mission are shown, and will also be updated every six months, in the accompanying descriptive README file.辐射效应宇宙射线望远镜（Cosmic Ray Telescope for the Effects of Radiation, CRaTER）自2009年起便搭载于美国国家航空航天局（NASA）的月球勘测轨道飞行器（Lunar Reconnaissance Orbiter, LRO），在月球轨道持续运行。其首要观测内容为源自行星际空间、受太阳活动调制的缓变银河宇宙射线（galactic cosmic rays, GCRs）通量。本数据集收录了探测器在背向月面直射状态、且太阳高能粒子（solar energetic particle）活动处于平静期时测得的宇宙射线线性能量转移（Linear Energy Transfer, LET）能谱，时间跨度覆盖探测器抵达月球至今的全部时段。此类线性能量转移能谱可量化9.9 g/cm²屏蔽层后方的能量沉积（辐射剂量），该屏蔽层主要由组织等效塑料（Tissue-Equivalent Plastic, TEP）构成。本数据集为持续更新数据集，将每六个月新增一次线性能量转移能谱的测量数据。随附的说明性README文件中展示了本次任务周期内各项测量的变化情况图表，且该图表也将每六个月同步更新一次。