Manufacturing of aluminum mirrors for cryogenic applications

Kinast, Jan; Schlegel, Ralph; Kleinbauer, K.; Steinkopf, Ralf; Follert, Roman; Dorn, Reinhold J.; Lizon, Jean Louis; Hatzes, A. P.; Tünnermann, Andreas

doi:10.1117/12.2313126

Cited by 4 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The specifications related to the requirements R-TEL-M1-0212 and R-TEL-M1-0214, in terms of grain size and Mg2Si inclusion dimension, are not given by any provider but seems to be the most critical ones: to mitigate this problem, we are planning to adopt all the steps of a thermal process described in [3], applied to the mirror after the rough machine. Other fundamental papers related to aluminum mirrors are [1,2] describing the use and the characteristic of instruments that make use of aluminum mirrors. Table 3 below shows the list of providers that have been surveyed.…”

Section: Selection and Procurement Of The Aluminummentioning

confidence: 99%

Toward ARIEL’s primary mirror

Tozzi

Brucalassi

Canestrari

et al. 2022

Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave

View full text Add to dashboard Cite

Ariel (Atmospheric Remote-Sensing Infrared Exoplanet Large Survey) is the adopted M4 mission of ESA "Cosmic Vision" program. Its purpose is to conduct a survey of the atmospheres of known exoplanets through transit spectroscopy. Launch is scheduled for 2029.Ariel scientific payload consists of an off-axis, unobscured Cassegrain telescope feeding a set of photometers and spectrometers in the waveband between 0.5 and 7.8 µm, and operating at cryogenic temperatures.The Ariel Telescope consists of a primary parabolic mirror (M1) with an elliptical aperture of 1.1 m of major axis and 0.7 m of minor axis, followed by a hyperbolic secondary (M2) , a parabolic recollimating tertiary (M3) and a flat folding mirror (M4).The Primary mirror is a very innovative device made of lightened aluminum. Aluminum mirrors for cryogenic instruments and for space application are already in use, but never before now it has been attempted the creation of such a large mirror made entirely of aluminum: this means that the production process must be completely revised and finetuned, finding new solutions, studying the thermal processes and paying a great care to the quality check.

show abstract

Section: Selection and Procurement Of The Aluminummentioning

confidence: 99%

Toward ARIEL’s primary mirror

Tozzi

Brucalassi

Canestrari

et al. 2022

Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave

View full text Add to dashboard Cite

show abstract

“…Aluminium is a common construction material for fabrication of high-performance mirror devices since it exhibits high reflection coefficient in a broad spectral wavelength range from the infrared (IR) to the ultraviolet (UV) [1]. Due to its good mechanical machinability, light weight, low cost and high thermal conductivity, aluminium optics are rather attractive for spacecraft systems [2], high resolution imaging [3] and cryogenic applications [4,5]. Single-point diamond turning (SPDT) is a common manufacturing procedure for IR applications.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, a post-finishing step has to be applied for improving figure error and surface roughness [6]. Direct aluminium finishing techniques are under consideration in view of avoiding thermal stress during application when an additional amorphous coating such as nickel phosphorous (NiP) is used [2,4,5,7]. Increasing demands on accuracy of surface quality for applications in the shortwavelength range claim improved ultra-precise surface machining techniques.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the optical properties after surface error correction of aluminium mirror surfaces

Ulitschka

Bauer

Frost

et al. 2021

J. Eur. Opt. Soc.-Rapid Publ.

View full text Add to dashboard Cite

Ion beam finishing techniques of aluminium mirrors have a high potential to meet the increasing demands on applications of high-performance mirror devices for visible and ultraviolet spectral range. Reactively driven ion beam machining using oxygen and nitrogen gases enables the direct figure error correction up to 1 μm machining depth while preserving the initial roughness. However, the periodic turning mark structures, which result from preliminary device shaping by single-point diamond turning, often limit the applicability of mirror surfaces in the short-periodic spectral range. Ion beam planarization with the aid of a sacrificial layer is a promising process route for surface smoothing, resulting in successfully reduction of the turning mark structures. A combination with direct surface smoothing to perform a subsequent improvement of the microroughness is presented with a special focus on roughness evolution, chemical composition, and optical surface properties. As a result, an ion beam based process route is suggested, which allows almost to recover the reflective properties and an increased long-term stability of smoothed aluminium surfaces.

show abstract

“…The findings of the above mentioned research have been used to determine a final layer for a protected Ag-coating, which was applied for reflectors utilized in the CRIRES + -instrument. The reflectors were manufactured (by diamond turning and polishing) and coated at the Fraunhofer IOF in Jena [23]. The CRIRES + -instrument is an instrument which will be installed at the Very Large Telescope (VLT).…”

Section: Introductionmentioning

confidence: 99%

Protected silver coatings for reflectors

Schwinde

Schürmann

Schlegel

et al. 2019

International Conference on Space Optics — ICSO 2018

Self Cite

View full text Add to dashboard Cite

For ground-and spaced based applications, Ag coated reflectors are indispensable because of their high reflectivity. The transport, assembling and storage of these reflectors takes a long time, before they are finally commissioned for the actual applications. To endure this period without a decrease of reflectivity, protective coatings with a final layer, which offers a high resistance to aqueous solutions and a low mechanical stress should be used. These criteria were taken into account for the selection of a final layer for a protected Ag-coating, which was applied for reflectors utilized in the CRIRES +instrument (an IR spectrograph used at the VLT). Reactively sputtered Al2O3, SiO2 and Si3N4 layers were investigated with regard to these criteria. In aqueous (basic) solutions, the investigated Si3N4 layers are more stable than the SiO2 layers, and the SiO2 layers are more stable than the Al2O3 layers. This shows the influence of the intrinsic material properties. The mechanical stress of the sputtered layers depends on the deposition conditions and thus on the selected parameters. A Si3N4 layer with a high resistance to aqueous solutions also offers a low and stable mechanical stress. Therefore, the depositionparameters which have been used for this layer were applied for sputtering the final layer of the protected Ag-coating for the reflectors.

show abstract

Manufacturing of aluminum mirrors for cryogenic applications

Cited by 4 publications

References 2 publications

Toward ARIEL’s primary mirror

Toward ARIEL’s primary mirror

Improvement of the optical properties after surface error correction of aluminium mirror surfaces

Protected silver coatings for reflectors

Contact Info

Product

Resources

About