Development and production of hard X-ray multilayer optics for HEFT

Koglin, Jason E.; Christensen, Finn Erland; Chonko, Jim; Craig, William W.; Decker, Todd; Jimenez-Garate, Mario A.; Gunderson, K.; Hailey, Charles J.; Harrison, Fiona A.; Jensen, Christian Damsgaard; Sileo, Mike; Windt, David L.; Yu, Haitao

doi:10.1117/12.461479

Cited by 21 publications

(17 citation statements)

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“…The energy limits of grazing incidence optics are being pushed to 100 keV [2][3][4], but small grazing angles limit the effective areas feasible and polishing tolerances inhibit extremely good angular resolution. Other X-ray missions under study [5] could considerably improve sensitivity and spectral resolution, however they will not emphasize improvements in angular resolution, which will remain >10 3 times worse than the diffraction-limit, inhibiting their use for measurements requiring high-angular resolution.…”

Section: Astronomical Imaging Systemsmentioning

confidence: 99%

Development of a Deep Silicon Phase Fresnel Lens Using Gray-Scale Lithography and Deep Reactive Ion Etching

Morgan

Waits

Krizmanic

et al. 2004

J. Microelectromech. Syst.

127

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A phase Fresnel lens (PFL) could achieve higher sensitivity and angular resolution in astronomical observations than the current generation of gamma and hard x-ray instruments. For ground tests of a PFL system, silicon lenses must be fabricated on the micro-scale with controlled profiles to enable high lens efficiency. Thus, two MEMS-based technologies, gray-scale lithography and deep reactive ion etching (DRIE), are extended to create multiple controlled step heights in silicon on the necessary scale.A Gaussian approximation is introduced as a method of predicting a photoresist gray level height given the amount of transmitted light through a grayscale optical mask. Etch selectivity during DRIE is then accurately controlled by introducing an oxygen-only step to a standard Bosch cycle to produce the desired scaling factor between the photoresist and silicon profiles. Finally, a profile evaluation method is developed to calculate the expected efficiency of measured silicon profiles. Calculated efficiencies above 87% have been achieved.

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Section: Astronomical Imaging Systemsmentioning

confidence: 99%

Development of a Deep Silicon Phase Fresnel Lens Using Gray-Scale Lithography and Deep Reactive Ion Etching

Morgan

Waits

Krizmanic

et al. 2004

J. Microelectromech. Syst.

127

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“…An air-bearing Linear Variable Differential Transformer (LVDT) built by CPPI ‡ is used to perform low force surface metrology on the back surface of the mounted mirrors. 11,12 Since the thickness of mirror substrates is very uniform in the axial direction, surface metrology performed on the back-side of the glass replicates the front surface figure which serves to focus the X-rays. Complete surface figure maps of each mirror shell are obtained from LVDT data recorded along the entire axial length of both upper and lower shells at 144 different azimuth positions.…”

Section: Optics Design and Fabricationmentioning

confidence: 99%

First results from the ground calibration of the NuSTAR flight optics

Koglin

Barrière

et al. 2011

SPIE Proceedings

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NuSTAR is a hard X-ray satellite experiment to be launched in 2012. Two optics with 10.15 m focal length focus Xrays with energies between 5 and 80 keV onto CdZnTe detectors located at the end of a deployable mast. The FM1 and FM2 flight optics were built at the same time based on the same design and with very similar components, and thus the performance of both is expected to be very similar. We provide an overview of calibration data that is being used to build an optics response model for each optic and describe initial results for energies above 10 keV from the ground calibration of the flight optics. From a preliminary analysis of the data, our current best determination of the overall HPD of both the FM1 and FM2 flight optics is 52", and nearly independent of energy. The statistical error is negligible, and a preliminary estimate of the systematic error is of order 4". The as-measured effective area and HPD meet the toplevel NuSTAR mission sensitivity requirements.

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“…We have upgraded our mounting hardware and now position the spacers much more accurately, thus reducing the possible error contribution from spacer misalignment to a negligible level (<1", c.f., Ref. 8 for discussion on spacer alignment errors).…”

Section: Assembly Of Heft Optics Modulesmentioning

confidence: 99%

“…This analysis procedure is quite effective and has been shown to compare well with X-ray data in past prototype development. 8,9 A raytrace procedure is used to generate the two-bounce image off the upper/lower shell combination. Since the LVDT scans are stopped and started by hand, the scans are normally not uniformly performed over the entire 10 cm shell length.…”

Section: Lvdt Metrologymentioning

confidence: 99%