Photomultiplier tubes (PMTs) are widely used in imaging atmospheric Cherenkov telescopes. Their response can depend on the telescope pointing direction through changes in their orientation relative to the geomagnetic field. Such a dependence was indicated during the calibration campaign of the CTAO LST-1. In this work, the LST-1 calibration data are analyzed to quantify the gain dependence in terms of the geomagnetic field, and dedicated laboratory measurements are performed to test the hypothesis that the observed dependence originates from magnetic-field effects. Both the on-site and laboratory measurements show a consistent dependence of the PMT gain on the magnetic field, while the laboratory measurements further separate the effects on the gain and the excess noise factor. These results provide a clearer understanding of the gain variation observed in LST-1 in terms of magnetic-field effects.
The Cherenkov Telescope Array Observatory (CTAO) will observe very-high-energy gamma rays with unprecedented sensitivity and will study a large variety of gamma-ray sources with high statistics. Precision measurements will allow researchers to search for subtle spectral and morphological features beyond simple power-la...
M. Gaug, R. Zanin, M. Doro· Astronomical Telescopes + In...· 0 citations
AU-scale structures in the interstellar medium have become relevant across several areas of astrophysics, from ISM microphysics to pulsar timing arrays and cosmic-ray (CR) propagation. Current sheets formed at magnetic-field reversals have drawn particular attention because they can deflect the dominant GeV CR populati...
Jacob Yen, Daniel Baker, Dong-Zi Li et al.· 0 citations
The Spectrometer/Telescope for Imaging X-rays (STIX) on board Solar Orbiter provides imaging information on the X-ray sources in solar flares by modulating the emitted radiation with pairs of grids made of stacked tungsten layers. Optical measurements of the grids were taken on the ground and utilized to derive an init...
P. Massa, A. Volpara, M. Stiefel et al.· Solar Physics· 0 citations
The Cherenkov Telescope Array Observatory (CTAO) is establishing two sites: in La Palma, Canary Islands, and Paranal, Chile, to observe gamma-ray sky from 0.03 to 300 TeV with high sensitivity and resolution. It involves 70 air Cherenkov telescopes of various sizes. Four 23-meter parabolic Large-Sized Telescopes (LSTs)...
G. Sironi, L. Proserpio, G. Pareschi et al.· Astronomical Telescopes + In...· 0 citations
The Coronal Spectropolarimeter for Airborne Infrared Research (CORSAIR) is a balloon-borne infrared coronagraph and spectropolarimeter funded by NASA's Heliophysics Low Cost Access to Space (H-LCAS) program and currently under development at Smithsonian Astrophysical Observatory (SAO). CORSAIR will make global, long-du...
J. Samra, Alan Hsu, Vanessa Marquez et al.· Astronomical Telescopes + In...· 1 citation
We investigate an all-optical scheme for high-sensitivity measurements of the Earth's scale magnetic field ($B$). The scheme is based on the Bell-Bloom technique with frequency-modulated light. A single elliptically polarized light beam is used both for pumping the alkali-metal atoms and probing Larmor precession of th...
D. Brazhnikov, A. Makarov, K. Kozlova et al.· 0 citations
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