Performance and stability of mirror coatings for the ATHENA mission

Ferreira, Desiree Della Monica; Svendsen, Sara; Massahi, Sonny; Jafari, Atefeh; Vu, Lan M.; Korman, Jakob; Gellert, Nis C.; Christensen, Finn Erland; Kadkhodazadeh, Shima; Kasama, Takeshi; Shortt, Brian; Bavdaz, Marcos; Collon, Maximilien J.; Landgraf, Boris; Krumrey, Michael; Cibik, Levent; Schreiber, Swenja; Schubert, Anja

doi:10.1117/12.2313275

Cited by 18 publications

(12 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The coating process itself is currently being developed by DTU Space [20][21][22] and is then applied and tested on the industrial coating machine described above. First results of single, bi-and multi-layers of Ir and B4C coated on silicon using the industrial coating machine show very good results, demonstrating that the research grade quality can be matched with the mass production systems being prepared for Athena.…”

Section: Coating Process Developmentmentioning

confidence: 99%

Silicon pore optics mirror module production and testing

Collon¹,

Vacanti

Barrière

et al. 2018

Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

Self Cite

View full text Add to dashboard Cite

Silicon Pore Optics (SPO) has been established as a new type of x-ray optics that enables future x-ray observatories such as Athena. SPO is being developed at cosine with the European Space Agency (ESA) and academic and industrial partners. The optics modules are lightweight, yet stiff, high-resolution x-ray optics, that shall allow missions to reach an unprecedentedly large effective area of several square meters, operating in the 0.2 to 12 keV band with an angular resolution better than 5 arc seconds. In this paper we are going to discuss the latest generation production facilities and we are going to present results of the production of mirror modules for a focal length of 12 m, including x-ray test results.

show abstract

Section: Coating Process Developmentmentioning

confidence: 99%

Silicon pore optics mirror module production and testing

Collon¹,

Vacanti

Barrière

et al. 2018

Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

Self Cite

View full text Add to dashboard Cite

show abstract

“…The computation was repeated for three cases of optimized reflecting coatings. 6 In Fig. 3, central and bottom panels we report the results of the same computation for the cases of a 10 arcmin and 20 arcmin off-axis source.…”

Section: Effective Area Simulationmentioning

confidence: 99%

“…Experimental tests of the coating performance performed at DTU Space have shown instability of the B 4 C coating, and incompatibility with the industrial processes involved in the production of SPO mirror modules. 6 Silicon carbide (SiC) is recommended as replacement for B 4 C. For the configuration 3 the proposed coating baseline is Ir/SiC. 5,6 • The complex integration of the mirror assembly: considering the number of involved MMs, the misalignment contribution to be allocated in the error budget to the integration process should be carefully studied.…”

Section: Introductionmentioning

confidence: 99%

“…6 Silicon carbide (SiC) is recommended as replacement for B 4 C. For the configuration 3 the proposed coating baseline is Ir/SiC. 5,6 • The complex integration of the mirror assembly: considering the number of involved MMs, the misalignment contribution to be allocated in the error budget to the integration process should be carefully studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simulating the optical performances of the ATHENA x-ray telescope optics

Sironi¹,

Spiga

Ferreira

et al. 2018

Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

Self Cite

View full text Add to dashboard Cite

The ATHENA (Advanced Telescope for High Energy Astrophysics) X-ray observatory is an ESA-selected L2 class mission. In the proposed configuration, the optical assembly has a diameter of 2.2 m with an effective area of 1.4 m 2 at 1 keV, 0.25 m 2 at 6 keV, and requires an angular resolution of 5 arcsec. To meet the requirements of effective area and angular resolution, the technology of Silicon Pore Optics (SPO) was selected for the optics implementation. The ATHENA's optic assembly requires hundreds of SPOs mirror modules (MMs), obtained by stacking wedged and ribbed silicon wafer plates onto silicon mandrels to form the Wolter-I configuration. Different factors can contribute to limit the imaging performances of SPOs, such as i) diffraction through the pore apertures, ii) plate deformations due to fabrication errors and surface roughness, iii) alignment errors among plates in an MM, and iv) co-focality errors within the MMs assembly. In order to determine the fabrication and assembling tolerances, the impact of these contributions needs to be assessed prior to manufacturing. A set of simulation tools responding to this need was developed in the framework of the ESA-financed projects SIMPOSIuM and ASPHEA. In this paper, we present the performance simulation obtained for the recentlyproposed ATHENA configuration in terms of effective area, and we provide a simulation of the diffractive effects in a pair of SPO MMs. Finally, we present an updated sizing of magnetic diverter (a Halbach array) and the magnetic fields levels that can be reached in order to deviate the most energetic protons out of the detector field.

show abstract

“…This paper is restricted to the investigation of film stress effects on the shape of segmented silicon mirrors. To produce an x-ray mirror segment, a silicon substrate must be fabricated 5 and then coated, typically with a thin metal film, such as iridium [6][7][8][9] or a multilayered coating, [10][11][12] to efficiently reflect x-rays. Coatings are often deposited using magnetron sputtering, usually to maximize x-ray reflectivity, which results in a stressed film that deforms the thin mirror substrates, especially segmented mirrors.…”

Section: Introductionmentioning

confidence: 99%

Simulations of film stress effects on mirror segments for the Lynx X-ray Observatory concept

Chalifoux

Yao

Heilmann

et al. 2019

J. Astron. Telesc. Instrum. Syst.

View full text Add to dashboard Cite

The Lynx X-ray Observatory concept, under study for the 2020 NASA Decadal Survey, will require a telescope with ∼2 m 2 of effective area and a point-spread function (PSF) with ∼0.5-arc sec half-power diameter (HPD) to meet its science goals. This requires extremely accurate thin grazing-incidence mirrors with a reflective x-ray coating. A mirror coating, such as 15-nm-thick iridium, can exhibit stress exceeding 1 GPa, significantly deforming segmented mirrors and blurring the PSF. The film stress and thickness are neither perfectly repeatable nor uniform. We use finite element analysis and ray tracing to quantify the effects of integrated stress inaccuracy, nonrepeatability, nonuniformity, and postmounting stress changes on segmented mirrors. We find that if Lynx uses segmented mirrors, it will likely require extremely small film stress (∼10 MPa) and nonuniformity (<1%). We show that realigning mirrors and matching complementary mirror pairs can reduce the HPD from uniform film stress by a factor of 2.3× and 5×, respectively. Doubling mirror thickness produces much less than the 4× HPD reduction that would be expected from a flat mirror. The x-ray astronomy community has developed numerous methods of reducing the PSF blurring from film stress, and Lynx may require several of these in combination to achieve 0.5 arc sec HPD using segmented mirrors.

show abstract

Performance and stability of mirror coatings for the ATHENA mission

Cited by 18 publications

References 16 publications

Silicon pore optics mirror module production and testing

Silicon pore optics mirror module production and testing

Simulating the optical performances of the ATHENA x-ray telescope optics

Simulations of film stress effects on mirror segments for the Lynx X-ray Observatory concept

Contact Info

Product

Resources

About