Spectral Callibration of the Fluorescence Telescopes of the Pïerre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

ASTROPARTICLE PHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 95C p. 44 - 56

0927-6505

We present a novel method to measure precisely the relative spectral response of the fluorescence telescopesof the Pierre Auger Observatory. We used a portable light source based on a xenon flasher anda monochromator to measure the relative spectral efficiencies of eight telescopes in steps of 5 nm from280 nm to 440 nm. Each point in a scan had approximately 2 nm FWHM out of the monochromator. Differentsets of telescopes in the observatory have different optical components, and the eight telescopesmeasured represent two each of the four combinations of components represented in the observatory. Wemade an end-to-end measurement of the response from different combinations of optical components,and the monochromator setup allowed for more precise and complete measurements than our previousmulti-wavelength calibrations. We find an overall uncertainty in the calibration of the spectral responseof most of the telescopes of 1.5% for all wavelengths; the six oldest telescopes have larger overall uncertaintiesof about 2.2%. We also report changes in physics measurables due to the change in calibration,which are generally small.