Use of Energy Measurements in the CALET Ultra-Heavy Cosmic-Ray Analysis*

The Calorimetric Electron Telescope (CALET), launched to the ISS in August 2015 and in continuous operation since, measures cosmic-ray (CR) electrons, nuclei, and gamma rays. CALET, with its 27 radiation length deep Total Absorption Calorimeter (TASC), measures particle energy, allowing for the determination of spectra and secondary to primary ratios of the more abundant CR nuclei through ₂₈Ni, while the main charge detector (CHD) can measure Ultra-Heavy (UH) CR nuclei through ₄₀Zr. Previous CALET UHCR analyses have used a special high duty cycle (~90%) UH trigger that does not require passage through the TASC. After 6 years of operation, the size of the UH data set is comparable to the first flight of the balloon-borne SuperTIGER instrument without the need for an atmospheric correction. Previous analysis has used time- and position-dependent detector response corrections based on ₁₄Si and ₂₆Fe and an angle-dependent geomagnetic cutoff rigidity selection to show abundances of even nuclei in agreement with SuperTIGER. This analysis improves resolution by restricting UH events to the ~1/6 that pass through both the TASC and CHD, providing energy information for the charge determination. Our results are compared to previous CALET work as well as ACE-CRIS, SuperTIGER, and HEAO-3.