Novel Technologies for Future Large X-ray Telescopes

	X-ray Optics...Optics for XEUS
Novel Technologies for Future Large X-ray Telescopes
R. Hudec, , L. Pína, A. Inneman, V. Semencová, M. Skulinová, L. véda, V. Broek, J. ik, M. Míka, R. Kačerovský, T. Kubina,

The parameters of the GTF may be improved by:

optimization of the glass material (limited)

optimization ot the mandrel material/design

optimization of the GTF process

optimization of the GTF temperature and duration

Expectations (goals)

microroughness of float-glass not degradated - ~ 0.5 nm rms

deviation PV < 0.02 microns

FLOAT FLAT GLASS 70 x 100 x 0.3 mm (Interferometer ZYGO)
	profile plot
3D plot

FLOAT FLAT GLASS 70x100x0.3 mm
Optical profilometer STIL	roughness analysis
shape analysis dashed line	shape analysis

Various approaches in Glass Thermal Forming	Glass Thermal Forming - one of studied approaches - Parabolic Profile

Float glass samples: 24x76x1 mm - GTF using a composite mandrel	THIN GLASS FOILS SHAPING .PARABOLA 100x150x0.75 mm

Thermally bent glass foils, test cylindrical surface R = 1.3 m, 30 x 30 cm, 0.75 mm thick	profile measurement need to improve the plate holding

Comparison of profile of mandrel and replicated flass foil: the deviations are typically less than
2 ... 3 microns, replica better fit the ideal profile, further improvements and optimization is in progress

Deviations of the real profile of the formed glass foil from the ideal profile for T=630 C for "optimized" T (670 C) they are < 1 micron (peak to valley), for too low T (560 T) however 45 microns

GLASS BENT MIRROR, 100x150x0.75 mm Shape analysis from profilometer PARABOLA	THE ROLE OF THE TEMPERATURE IN THE FORMING
y = 0 => middle of the sample y = 49.5 => edge of the sample	The influence of T: green T1, red T2, blue T3

The temperature dependence of the deviation from the ideal surface

Preliminary results - GTF

surface microroughness not degradated down to measuring accuracy ~ 0.5 ... 1 nm

profile deviations 0.7 micron (peak-valley) in the best case, expectations < 0.02 micron

sensitive to T = need for optimization

sensitive to mandrel design/material/process = need for optimization

SUMMARY

Samples of test X-ray mirrors have been produced using novel technologies

Shaped thin glass mirrors and Si mirrors have been succeslully produced

Both approaches show promising results justifying further efforts in these directions

Results of measurements on float glass samples formed at different temperatures-the dependence of the slope deviation on the temperature. The slope deviations from the ideal profile strongly depends on forming temperature and can be less than 1 micron. Tg is the transformation temperature of the used glass

We acknowledge collaboration with ON Semiconductor CR, Ronov pod Radhotěm, Optical Development Workshop of the AS CR Turnov, and TTS sro Prague

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