Optimizing Selection Criteria for the CALET Ultra-Heavy Cosmic Ray Analysis

CALET, the Calorimetric Electron Telescope, launched to the International Space Station in August 2015 and in continuous operation since, has gathered over seven years of data so far. CALET is able to measure cosmic-ray (CR) electrons, nuclei, and gamma rays and 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

_{28}

Ni, while the main charge detector (CHD) can measure Ultra-Heavy (UH) CR nuclei through

_{40}

Zr. CALET UHCR analyses use a special high duty cycle UH trigger with an expanded geometry that does not require passage through the TASC. To effectively analyze UHCR trigger events, a number of screens and corrections have been developed for the analysis. From time- and position-dependent detector response corrections based on

_{14}

Si and

_{26}

Fe, to an angle-dependent geomagnetic cutoff rigidity selections and minimum deposited energy screens, a number of methods have been explored to optimize UH statistics to varying effect. In this work, we aim to show how these event selection screens and corrections have been developed, how the rigidity screens shown previously by Rauch et al compare to the newer TASC methodology shown in our other ICRC paper, and how TASC selections may be used to influence analysis on the full UH-trigger dataset.

radiation: length
particle: energy
electron: detector
calorimeter: absorption
CALET
nucleus
trigger
cosmic radiation
satellite
statistics

References(6)

Figures(0)

[1]

for the CALET Collaboration, Highlights from the CALET observations for 7.5 years on the International Space Station, in proceedings of The 38th International Cosmic Ray Conference

S. Torii

[2]

Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV/ $n$ to 2.0 TeV/ $n$ with the Calorimetric Electron Telescope on the International Space Station

CALET

Collaboration

•

O. Adriani
(
- Florence U. and
- INFN, Florence
)

et al.

- Phys.Rev.Lett. 126 (2021) 24, 241101
•
e-Print:
- 2106.08036
•
DOI:
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[3]

Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8 GeV/n to 240 GeV/n with CALET on the International Space Station

CALET

Collaboration

•

O. Adriani
(
- INFN, Florence
)

et al.

- Phys.Rev.Lett. 128 (2022) 13, 131103
•
e-Print:
- 2204.00845
•
DOI:
- 10.1103/PhysRevLett.128.131103

[4]

COSMIC RAY ISOTOPE ABUNDANCES FROM CHROMIUM TO NICKEL

- Astrophys.J. 230 (1979) 607-620
•
DOI:
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[5]

Progress on Ultra-Heavy Cosmic-Ray Analysis with CALET on the International Space Station in proceedings of The 37th International Cosmic Ray Conference

W.V. Zober

[6]

Results of the Ultra-Heavy Cosmic-Ray Analysis with CALET on the International Space Station, in proceedings of The 38th International Cosmic Ray Conference,

W.V. Zober
,
B.F Rauch