Galactic cosmic ray linear energy transfer spectra at the Moon during solar minimum

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER), on-board the Lunar Reconnaissance Orbiter (LRO), measures the linear energy transfer (LET) of galactic cosmic rays. On timescales on the order of a decade or less, the Sun's interplanetary magnetic field is the dominant modulator of galactic cosmic rays observed at one astronomical unit from the Sun. We have already observed changes in the LET spectra due to the modulation of lower energy GCRs as solar activity increases. Thus, through CRaTER observations we are able to characterize precisely the effects of increasing solar activity on the dose and its components broken down via LET spectra. This work provides critical information to assess how the radiation hazard from cosmic rays changes over the solar cycle.