Haleakala neutron monitor redeployment and calibration with AMS data

Abstract

Since the 1950s, neutron monitors (NMs) have successfully measured both the long-term and the short-term variation of Galactic Cosmic Rays (GCRs). NMs are also sensitive to solar energetic particles (SEPs) and solar neutron particles (SNPs), both detected as ground level enhancements. Since SNPs are not affected by the interplanetary magnetic field, they retain direct information about the nuclear reactions happening near the SEP acceleration site. The global NM network has still a huge gap over the equatorial Pacific for measuring high energy GCRs and SNPs which are best measured at low latitudes. We plan to extend the coverage of the world wide NM network for SNP and GCR observations by redeploying the Haleakala NM station (HLEA) on Maui, in time for the upcoming solar maximum (around 2025). Since NMs can only measure the total count rate, it is not trivial to derive the actual particle flux and to compare different station responses. We plan to calibrate the HLEA with the future AMS daily proton fluxes, extended until the ISS decommission date now planned in 2031, and to perform extensive Mote Carlo simulations of the detector and surrounding environment. The initial phase of the project has already started. Status of the upcoming HLEA NM detector is reported.