The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F24%3A00635896" target="_blank" >RIV/68378271:_____/24:00635896 - isvavai.cz</a>

Result on the web

<a href="https://pos.sissa.it/444/398/pdf" target="_blank" >https://pos.sissa.it/444/398/pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.22323/1.444.0398" target="_blank" >10.22323/1.444.0398</a>

Result language

angličtina

Original language name

The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory

Original language description

The determination of the energy spectrum features with low systematic uncertainty is crucial for interpreting the nature of cosmic rays. In this study, we conducted a measurement of the energy spectrum at the Pierre Auger Observatory using a surface detector with a calorimetric energy scale set by a fluorescence detector. The surface detector consists of an array of water-Cherenkov detectors that extends over 3000 km² with 1500 m spacing. Additionally, two nested arrays of the same kind with 750 m and 433 m spacing were utilized to lower the energy threshold of the measurements. This contribution presents, for the first time, the spectrum measured with the 433 m array, which reduces the energy threshold down to 63 PeV, nearly half the energy at which we previously published a steepening using the 750 m array. Our measurements include a characterization of the spectral features of the flux steepening around 230 PeV, known as the second-knee. The study benefits from a nearly 100% duty cycle and geometrical exposure. Notably, this is the first simultaneous measurement of the second knee energy and spectral indexes before and after the break, using a surface detector with an energy scale predominantly independent of air shower simulations and assumptions regarding hadronic interaction models.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

10303 - Particles and field physics

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Proceedings of Science

ISBN

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ISSN

1824-8039

e-ISSN

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Number of pages

13

Pages from-to

398

Publisher name

Sissa Medilab srl

Place of publication

Trieste

Event location

Nagoya

Event date

Jul 26, 2023

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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