Result: Stepper motors at LHe temperatures in astronomical mid-infrared instrumentation

Title:
Stepper motors at LHe temperatures in astronomical mid-infrared instrumentation
Authors:
THEIL, D. S, STENCEL, R. E, KLEBE, D. I, FLAMING, D, BELGUM, J
Source:
Optomechanical engineering and vibration control (Denver CO, 20-23 July 1999)SPIE proceedings series. :376-383
Publisher Information:
Bellingham WA: SPIE, 1999.
Publication Year:
1999
Physical Description:
print, 8 ref
Original Material:
INIST-CNRS
Subject Terms:
Electronics, Electronique, Optics, Optique, Physics, Physique, Telecommunications, Télécommunications, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Astronomie, Astronomy, Astronomie fondamentale et astrophysique. Instrumentation, techniques, et observations astronomiques, Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations, Techniques d'observation et de réduction des données. Simulation et modélisation par ordinateur, Observation and data reduction techniques. Computer modeling and simulation, Polarimétrie, Polarimetry, Astronomie IR, Infrared astronomy, Astronomía IR, Composant optique, Optical component, Componente óptico, Conception système, System design, Concepción sistema, Cryogénie, Cryogenics, Formation image, Image forming, Hélium liquide, Liquid helium, Lame onde, Wave plate, Placa onda, Moteur pas à pas, Stepping motors, Polarimètre, Polarimeters, Polarimétrie, Polarimetry, Rayonnement IR moyen, Mid infrared radiation, Radiación infrarroja media, Sensibilité, Sensitivity, Sous système, Subsystem, Subsistema
Document Type:
Conference Conference Paper
File Description:
text
Language:
English
Author Affiliations:
University of Denver, Physics and Astronomy Dept. 2112 E Wesley Ave., Denver, CO 80208, United States
University of Colorado, Campus Box 389, Boulder, CO, 80309-0389, United States
Sutter Instrument Company, 51 Digital Drive, Novato, CA, 94949, United States
Access URL:
http://pascal-francis.inist.fr/vibad/index.php?action=search&terms=1172840
Rights:
Copyright 2000 INIST-CNRS
CC BY 4.0
Sauf mention contraire ci-dessus, le contenu de cette notice bibliographique peut être utilisé dans le cadre d’une licence CC BY 4.0 Inist-CNRS / Unless otherwise stated above, the content of this bibliographic record may be used under a CC BY 4.0 licence by Inist-CNRS / A menos que se haya señalado antes, el contenido de este registro bibliográfico puede ser utilizado al amparo de una licencia CC BY 4.0 Inist-CNRS
Notes:
Astronomy
Accession Number:
edscal.1172840
Database:
PASCAL Archive

Further Information

The University of Denver is now completing construction of a mid-infrared imaging polarimeter dubbed TNTCAM Mark II. The instrument will be the only one of its kind capable of attaining polarimetric accuracy of 0.2 % across the 5 25 micron spectral interval. This sensitivity is only attainable by cooling the transmissive polarizing optics to liquid helium (LHe) temperatures. A major technical challenge in the design of this instrument has been finding a way to modulate the polarization signature of the incoming beam at a rate sufficient to combat the degrading effects of the atmosphere. Our group has chosen to quickly rotate a half-waveplate situated on the cold (i.e. 4 degrees Kelvin) work-surface. The waveplate is rotated between two fixed positions separated by 45 degrees at a rate of 1 Hz to obtain one of the two Stokes parameters required to measure linear polarization. The waveplate is then offset by 22.5 degrees and then rotated again at 1 Hz between two positions separated by 45 degrees to obtain the other Stokes parameter. In addition to rotating the waveplate, the waveplate itself must be moved out of the beam during normal imaging applications. In this paper we present the design and the results of our moving optical componenets susbsytem. Five cryostepper motors drive these mechanisms. This instrument is being developed under NSF grant AST-9724506 and is slated for community access in January 2000.