Thin gold layer in NiCo and Ni electroforming process: optical surface characterization

Sironi, G.; Spiga, D.; Raimondi, Lorenzo; Pareschi, G.; Orlandi, A.; Borghi, G.; Missaglia, Nadia; Negri, B.

doi:10.1117/12.857195

Cited by 6 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As for the TDM1 [6] , the thickness of the Au coating used as mirror release agent from these mandrels is reduced to just 50 nm, to minimize the substrate roughness of the mirror [16] . The gold layer represents therefore the substrate surface onto which the multilayer coating is deposited.…”

Section: Tdm2mentioning

confidence: 99%

“…Unlike the shell 350 of the TDM2, however, no multilayer coating was deposited on the mirror: the reflective layer is a simple gold layer with a 50 nm thickness, a value chosen to minimize the substrate roughness of the mirror [16] . This shell was aimed at demonstrating the capability to obtain an angular resolution close to 15 arcsec also with the largest mirror shells of the NHXM.…”

Section: Tdm3mentioning

confidence: 99%

See 1 more Smart Citation

The optics system of the New Hard X-ray Mission: status report

et al. 2011

View full text Add to dashboard Cite

The New Hard X-ray Mission (NHXM) is a space X-ray telescope project focused on the 0.2 to 80 keV energy band, coupled to good imaging, spectroscopic and polarimetry detectors. The mission is currently undergoing the Phase B study and it has been proposed to ESA as a small-size mission to be further studied in the context of the M3 call; even if the mission was not downselected for this call, its study is being continued by ASI. The required performance is reached with a focal length of 10 m and with four mirror modules, each of them composed of 70 NiCo electroformed mirror shells. The reflecting coating is a broadband graded multilayer film, and the focal plane is mounted onto an extensible bench. Three of the four modules are equipped with a camera made of two detectors positioned in series, a Silicon low energy detector covering the range 0.2 to 15 keV and a high energy detector based on CdTe sensitive from 10 keV up to 120 keV. The fourth module is dedicated to the polarimetry to be performed with enhanced imaging capabilities. In this paper the latest development in the design and manufacturing of the optics is presented. The design has been optimized in order to increase as much as possible the effective area in the high-energy band. The manufacturing of the mirror shells benefits from the latest development in the mandrel production (figuring and polishing), in the multilayer deposition and in the integration improvements.

show abstract

Section: Tdm2mentioning

confidence: 99%

Section: Tdm3mentioning

confidence: 99%

The optics system of the New Hard X-ray Mission: status report

et al. 2011

View full text Add to dashboard Cite

show abstract

“…A noticeable effort [11] has been made at INAF/Brera Astronomical Observatory (OAB) and Media-Lario Technologies (MLT) to upgrade the Nickel electroforming technique in order to maintain a good angular resolution in hard X-rays with a mirror thickness-to-radius ratio smaller than XMM's by a two-fold factor, and in spite of the stress induced by the multilayer coating. Prototypes of NHXM mirror modules with a few mirror shells were manufactured [9] , aiming at demonstrating the feasibility of mirrors with such angular resolutions, e.g., adopting an electroformed Nickel-Cobalt alloy, stiffer than pure Nickel [11] , and reducing the thickness of the gold layer used for the mirror release to improve the roughness [12] . The direct performance verification was done by measuring the X-ray PSF (Point Spread Function) up to 50 keV in full-illumination setup at PANTER (MPE, Germany) [13] , a reference X-ray facility for calibration of X-ray telescopes like ROSAT, Beppo-SAX, JET-X, SOHO/CDS, ABRIXAS, Chandra LETG, XMM, SWIFT/XRT, Suzaku.…”

Section: Introductionmentioning

confidence: 99%

Angular resolution measurements at SPring-8 of a hard x-ray optic for the New Hard X-ray Mission

et al. 2011

Self Cite

View full text Add to dashboard Cite

The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (< 0.25 deg) grazing angles to enhance the reflectivity of reflective coatings. On the other hand, to obtain large collecting area, large mirror diameters (< 350 mm) are necessary. This implies that mirrors with focal lengths ≥10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for the NHXM hard X-ray imaging telescope (0.3 -80 keV), with a predicted HEW (Half Energy Width) close to 20 arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.

show abstract

“…In this process, the Gold layer acts both as a soft X-ray reflecting layer, and as a release agent since its adhesion to the electrochemical Nickel of the mandrel is very low. A particular attention has to be paid to the optimization of the Gold layer thickness [22], that has to be thick enough to chemically isolate the mirror Nickel from the Nickel coating of the mandrel, but at the same time thin enough to limit the growth of the roughness. A multilayer coating can be finally deposited on the inner side of the mirror shell by means of two linear sources [23].…”

Section: Inner Section -Ni Electroformingmentioning

confidence: 99%

“…The chemical electroless Nickel is a suitable material to superpolish the mandrel surface down to a few angstrom rms level, an important requirement for the replicated mirror to keep the X-ray scattering as low as possible. A thin film (50 -150 nm) of Gold [22] is then evaporated on the mandrel, and the Nickel mirror walls are grown on the Gold layer in an electrochemical bath. The mirror is finally released by cooling the mandrel, owing to the much higher CTE of the Aluminum mandrel with respect to the Nickel mirror.…”

Section: Inner Section -Ni Electroformingmentioning

confidence: 99%

The mirror module design for the cryogenic x-ray imaging spectrometer on-board ORIGIN

et al. 2011

View full text Add to dashboard Cite

ORIGIN is a medium size high-energy mission concept submitted to ESA in response to the Cosmic Vision call issued on July 2010. The mission will investigate the evolution of the Universe by performing soft X-ray high resolution spectroscopic measurements of metals formed in different astrophysical environments, from the first population III stars at z > 7 to the present large scale structures. The main instrument on-board ORIGIN will be a large format array of TES X-ray micro-calorimeters covering a FOV of 30' at the focal plane of a grazing incidence optical module with a focal length of 2.5 m and an angular resolution of 30'' HEW at 1 keV. We present the optical module design which is based on hybrid technologies, namely Silicon Pore Optics for the outer section and Ni electro-forming for the inner section, and we present the expected performances based on test measurements and ray-tracing simulations.

show abstract

Thin gold layer in NiCo and Ni electroforming process: optical surface characterization

Cited by 6 publications

References 0 publications

The optics system of the New Hard X-ray Mission: status report

The optics system of the New Hard X-ray Mission: status report

Angular resolution measurements at SPring-8 of a hard x-ray optic for the New Hard X-ray Mission

The mirror module design for the cryogenic x-ray imaging spectrometer on-board ORIGIN

Contact Info

Product

Resources

About