Optimisation des performances du système optique et estimation de la polarisation instrumentale de l'expérience embarquée sous ballon stratosphérique PILOT
type: Dataset
contact point: Organization
  fn: CCSD
keyword: emission-polarisee
keyword: infoeu-reposemanticsdoctoralthesis
keyword: stratospheric-balloon
keyword: primary-mirror
keyword: ballon-stratospherique
keyword: miroir-primaire
keyword: physastrimphysics-physicsastrophysics-astro-phinstrumentation-and-methods-for-astrophysic
keyword: polarization
keyword: sduastrimsciences-of-the-universe-physicsastrophysics-astro-phinstrumentation-and-methods
keyword: optical-system
keyword: systeme-optique
keyword: polarized-emission
keyword: domaine-submillimetrique
keyword: polarisation
keyword: submillimeter-range
keyword: theses
landing page: https://theses.hal.science/tel-00821057
description: The PILOT experiment will measure the polarized emission of interstellar dust grains, in the submillimeter range, at 240 and 550 μm. The scientific instrument will be on-board a stratospheric platform. A field of view of 0.8°×1° and a resolution of about one arc minute are needed to reach the scientific objectives. For this purpose, the use of an extended focal plane, a large diameter primary mirror and a re-imaging system is needed. For the off axis telescope, we must respect a combination of shape and angle between the primary and secondary mirror, in order to optimize the image quality and to minimize the instrumental polarization. The aim of my thesis work was the evaluation of the performances of this optical system and the prediction of their variations in flight conditions. All the optical elements, except the primary mirror will be cooled to 3 K. The variations of the primary mirror characteristics with the environment must be well known in order to obtain optimal performances during the flight. For the evaluation of these characteristics, I used tridimensional measurements, submillimeter characterization and modelling of the deformations in various environmental conditions. The method used for the primary mirror was applied to the lenses of the reimaging system too. The actual modelling of the optical system includes these results and show that the optical performances are nominal. Using this realistic modelling, an optimization of the positionning of each optical element was done for the integration of the instrument. The polarization degree of the dust grain emission is expected to be only a few percent. For the interpretation of the instrument signal, it is necessary to have a good knowledge of the instrumental polarization. Using modelling with Zemax software, I have determined the Stokes parameters for several positions of the optical axis of the half waveplate, different orientations of the incident polarization state and for a set of positions in the…
issued: 2026-05-11T04:51:40.401939
language: fr
modified: 2026-05-11T04:51:40.401943

test_moissonnage_selune
type: Agent

Optimisation des performances du système optique et estimation de la polarisation instrumentale de l'expérience embarquée sous ballon stratosphérique PILOT
type: Distribution
access URL: https://theses.hal.science/tel-00821057
format: HTML
issued: 2026-05-11T04:51:40.404344
modified: 2026-05-11T04:51:40.379840