Authors: Pierre-Simon Mangeard (University of Delaware, USA), John Clem (University of Delaware, USA), Paul Evenson (University of Delaware, USA), Warit Mitthumsiri (Mahidol University, Thailand), Pradiphat Muangha (Mahidol University, Thailand) , David Ruffolo (Mahidol University, Thailand), Alejandro Saiz (Mahidol University, Thailand), Waraporn Nuntiyakul (Chiang Mai University, Thailand), Chanoknan Banglieng (Rajamangala University of Technology, Thailand)

The spectral variations of the cosmic ray (CR) flux at Earth reflects the physical processes that affect the propagation of the CR within the heliosphere. The CR flux of low-energy is modulated by the long term magnetic variations of the Sun (11-year and 22-year solar cycle). The short term variations are driven by solar activity.

For the last decades, ground-based neutron monitors provide valuable observations of these variations. Neutron monitors are sensitive to the nucleonic component of the atmospheric cascade of particles produced by the interaction of the CR in the Earth’s atmosphere. Once corrected from environmental effects, the reported count rate from a NM station varies with the intensity and the spectral shape of the CR flux. Historically, multiple NM are needed to infer the latter.

We present here newly developed NM observations that aim to estimate spectral variations of the CR using a single neutron monitor. These new measurements are based on the time delays between recorded counts and their position within the monitor. We also present the new recording of complex bursts of hits in a NM. We discuss the sensitivity of these new observations to variations of the flux of CR striking Earth.