Update on Galactic Cosmic Ray Integral Flux Measurements in Lunar Orbit With CRaTER

Abstract

We report updated measurements of the integral fluxes of energetic protons, helium ions, and heavier ions as measured by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER). CRaTER is a particle telescope that has been operating aboard the Lunar Reconnaissance Orbiter since 2009. In an earlier report, we presented the methodology used to extract linear energy transfer spectra and integral fluxes for particles with sufficient energies to fully penetrate the telescope. Results were presented for the time span from late 2009 to the end of calendar year 2014, a period that encompassed the rise of solar activity from deep solar minimum to the weak maximum of Cycle 24. Here, we update the results with data obtained from that point in time through the end of 2018, in the declining phase of Cycle 24. Fluxes obtained in the most recent data are approaching the peak levels observed in late 2009 and early 2010. The results can be used as input to models of solar modulation of galactic cosmic rays and are also relevant to human exploration of deep space.

Resilient and agile engineering solutions to address societal challenges such as coronavirus pandemic

“…Researchers are reporting a decrease in solar activity leading to an increased flux of energetic particles in our galaxy [101]. Before it is too late to realize, and the entire human race wipes-off the face of the earth due to the climate change, we must take this pandemic as a wake-up call towards being considerate to the environment.…”

Long term variations of galactic cosmic radiation on board the International Space Station, on the Moon and on the surface of Mars

“…CRaTER (Spence et al, 2010) is a particle telescope composed of six silicon detectors, flying aboard the LRO spacecraft. LRO reached lunar orbit in July 2009, and the spacecraft's orbit was circularized in September 2009, and CRaTER has been recording GCR (see for example Zeitlin et al, 2019a) and SEP (see for example Schwadron et al, 2018) fluxes with very few interruptions since then. CRaTER data cover the time span from the deep cycle 23 solar minimum, the ascending phase and maximum of cycle 24, and the descending phase of cycle 24, which is ongoing at the time of this writing.…”

Detrended Fluctuation Analysis on the variation of Solar Energetic Particles during Solar Maximum and Minimum Periods

“…where pfu is particle ux unit) in the ux of MeV protons [Oh et al, 2010;Zeitlin et al, 2019]. The phenomena in which a class of SEPs with energy high enough to induce an atmospheric cascade with secondary particles prompt a sharp rise in count rate of ground-based detectors are generally referred to as ground level enhancements (GLEs) [Forbush, 1946;Reames, 1999;Gosling, 1993;Kahler, 1994].…”