Cosmic muon flux measurements from mid-latitude to Antarctica with a novel nested scintillator detector

We present cosmic muon flux measurements collected across two geomagnetically distinct environments using a novel concentric double-layer plastic scintillator telescope. The detector employs a nested geometry in which a cylindrical inner volume is coaxially enclosed within a cup-shaped outer scintillator, enabling active background rejection and wide-angle acceptance within a portable package. The scintillators were synthesized in-house from a custom epoxy-resin matrix. The system was deployed during the 10th Turkish Antarctic Expedition (TAE-X), with measurements taken at a mid-latitude baseline in Istanbul and at Horseshoe Island, Antarctica. The Antarctic flux exceeded the Istanbul baseline by approximately 41%, consistent with the reduced geomagnetic cutoff rigidity at polar latitudes. A Forbush decrease was also observed in Istanbul, coinciding with a Kp ∼ 8 geomagnetic storm driven by a coronal mass ejection and corroborated by simultaneous neutron monitor data. These results demonstrate the detector's suitability for continuous cosmic ray monitoring across diverse geomagnetic environments.