The MICADO first light imager for the ELT: design and performance of the Focal Plane Mechanism prototype

Fuente: arXiv
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Main Authors: Kravchenko, Kateryna, Rabien, Sebastian, Deysenroth, Matthias, Neumeier, Luis, Spallek, Lenard, Honsberg, Mathias, Barl, Lothar, Ziegleder, Julian, Sturm, Eckhard, Davies, Richard
Format: Preprint
Published: 2024
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author Kravchenko, Kateryna
Rabien, Sebastian
Deysenroth, Matthias
Neumeier, Luis
Spallek, Lenard
Honsberg, Mathias
Barl, Lothar
Ziegleder, Julian
Sturm, Eckhard
Davies, Richard
author_facet Kravchenko, Kateryna
Rabien, Sebastian
Deysenroth, Matthias
Neumeier, Luis
Spallek, Lenard
Honsberg, Mathias
Barl, Lothar
Ziegleder, Julian
Sturm, Eckhard
Davies, Richard
contents MICADO is a first-generation instrument for the ELT. It will provide diffraction-limited imaging in standard, astrometric, and coronagraphic modes and long-slit spectroscopy at near-infrared wavelengths. The core of the MICADO instrument is its cryostat, which cools the internal optical and mechanical subsystems to 80 K. Following a light ray entering the cryostat through the entrance window, the first mechanism it encounters is the Focal Plane Mechanism. It consists of two independent movable devices mounted in one assembly: the aperture wheel and the focal plane wheel. The primary purpose of the aperture wheel is to rapidly block the light path, which is needed to mitigate persistence on the detectors. The focal plane wheel holds field stops, calibration masks, slits, and coronagraphs. The positioning requirements for the wheel are dominated by the coronographic masks demanding a 15 $μ$m RMS repeatability. To fulfill this specification and avoid mechanical wear in the drive, a novel magnetically coupled gear system was developed at the Max Planck Institute for Extraterrestrial Physics (MPE). A magnetically coupled worm gear uses magnetic forces to transmit torque from the motor to the driven component without direct mechanical contact. This paper describes the design and performance of the magnetic drive and the first results of the focal plane wheel prototype tests in a cryogenic environment.
format Preprint
id arxiv_https___arxiv_org_abs_2409_01714
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The MICADO first light imager for the ELT: design and performance of the Focal Plane Mechanism prototype
Kravchenko, Kateryna
Rabien, Sebastian
Deysenroth, Matthias
Neumeier, Luis
Spallek, Lenard
Honsberg, Mathias
Barl, Lothar
Ziegleder, Julian
Sturm, Eckhard
Davies, Richard
Instrumentation and Methods for Astrophysics
MICADO is a first-generation instrument for the ELT. It will provide diffraction-limited imaging in standard, astrometric, and coronagraphic modes and long-slit spectroscopy at near-infrared wavelengths. The core of the MICADO instrument is its cryostat, which cools the internal optical and mechanical subsystems to 80 K. Following a light ray entering the cryostat through the entrance window, the first mechanism it encounters is the Focal Plane Mechanism. It consists of two independent movable devices mounted in one assembly: the aperture wheel and the focal plane wheel. The primary purpose of the aperture wheel is to rapidly block the light path, which is needed to mitigate persistence on the detectors. The focal plane wheel holds field stops, calibration masks, slits, and coronagraphs. The positioning requirements for the wheel are dominated by the coronographic masks demanding a 15 $μ$m RMS repeatability. To fulfill this specification and avoid mechanical wear in the drive, a novel magnetically coupled gear system was developed at the Max Planck Institute for Extraterrestrial Physics (MPE). A magnetically coupled worm gear uses magnetic forces to transmit torque from the motor to the driven component without direct mechanical contact. This paper describes the design and performance of the magnetic drive and the first results of the focal plane wheel prototype tests in a cryogenic environment.
title The MICADO first light imager for the ELT: design and performance of the Focal Plane Mechanism prototype
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2409.01714