X-RAY OPTICAL SYSTEM

Description

TECHNICAL FIELDS

[0001] The technical design relates to the X-ray optical system, with a proposal for the layout of thin reflection foils or small channels in the X-ray optical system, resulting in a greater aperture of the X-ray optical system (for range of 50 eV - 50 keV, i.e. EUV range, both soft and hard X-ray radiation).

BACKGROUND ARTS

[0002] Telescopes launched to the space until now to illustrate X-ray cosmic sources of radiation had the optical layout type Wolter I, being a combination of several rotationally symmetric parabolic and hyperbolic concave mirrors, which are laid out coaxially. Two relatively expensive and relatively complicated optical technologies are utilized (namely, the polishing and replication ones) to produce these mirrors.

[0003] The polishing technology utilizes standard optical methods. Polishing takes place in the expensive single-purpose equipment, where the internal surface of the rotationally symmetric substrate is machined over a period of several months. This technology is usable for mirrors dia. 0.5 m - 1.0 m and was used e.g. in case of CHANDRA satellite (1999).

[0004] Cosmic missions requiring smaller diameters of mirrors can be made only by applying the replication technology. For replication technology one has to manufacture very exact mandrels (regarding minimum macro and micro deformations), the production of which is complicated and financially costly. A layer of nickel (several millimeters thick), which will be subsequently removed from the mandrel, is electrochemically applied to these mandrels. The removed electrochemical film is the required optics which should copy the mandrel shape as best as possible. Mirrors prepared by the replication technology were used in XMM mission (1999).

[0005] At present, people are looking for technologies for preparation of cosmic X-ray telescopes type Wolter I designed with large diameters (4 m - 10 m). These optics place extraordinary demands in terms of precision, for the resolution of the optical system should be in order of several angle seconds. Such big optics cannot be produced in one piece any more. They must be assembled from smaller segments, which results in a number of technologic problems. Individual segments are based on thin, dimensionally exact substrates. Tens to hundreds thousands of these substrates will be required to assemble the whole optical system, depending on their size. Suitable materials seem to be glass and silicon substrates. Glass substrates are thermally molded on expensive precision mandrels. Another drawback of this technology consists in the necessity thermally to mold each foil separately, when one process of the thermal molding lasts roughly one day. So far, there has not been assembled any module from several molded/formed glass foils that the extreme requirements for resolution were complied with.

[0006] X-ray telescopes type Wolter I have a small field of view (up to 1°) and that is why one can detect only with great difficulties short flashes, and/or map out the sky in real time. In view of these circumstances "wide field of view" X-ray optics comes into play. It is the optical system of thin planar reflection foils cylindrically laid out, whether in one-dimensional (1D) or two-dimensional (2D) layout. The first theoretical design of such wide-angle layout was published by W.K.H. Schmidt in 1975. In 1979 J.R.P. Angel published another design, this time of a three-dimensional (3D) optical system based on rectangular small channels. The idea of a large cosmic telescope based on square modules was presented first by P. Gorenstein in 1998. This design was based on the geometric layout proposed by P. Kirkpatrick and A.V.J. Baez in 1948 (rectangular crossing of two aspherical surfaces), however, it does not solve the effective layout of square modules in circular apertures.

[0007] The closest similar technical solution of the geometric layout proposed herein was referred to in the professional journal "Optics for EUV, X-ray and Gamma-ray Astronomy IV (Proc. of SPIE Vol.7437)" by Richard Willingal and Frank H.P. Spaan in 2009. This article describes two geometric layouts (namely, the "sunflower" and "rectangular one"). Modules in the "sunflower" layout are orientated in the telescope so that the diagonals are mutually parallel and modules are laid out in a square network (in the center of circular aperture). "Rectangular" layout utilizes the aperture more effectively than the "sunflower" one. In case of this layout there arises the dead zone, where a part of modules is inactive. No dead zone already arises in the sunflower layout but the module layout is not tight and most effective. WO9209088 discloses an x-ray optical system according to the preamble of claim 1, in particular composed from kite-shaped segments arranged in 8-fold rotational symmetry.

DISCLOSURE OF INVENTION

[0008] According to the invention, there is provided an x-ray optical system according to claim 1. Preferred embodiments are set out in the dependent claims.

[0009] The proposed X-ray optical system has the advantage in that the layout of separate modules and segments effectively utilizes the aperture and covers the dead zone. The band homogeneity can be increased by means of rotation of the whole X-ray system around the system optical axis. In addition, manufacture of the designed optical system does not require expensive mandrels and commercially available substrates may be used. The dead zone can be filled with thin, rotationally symmetric foils laid out in another geometric layout, e.g. the parabolic or elliptic one, thus increasing the effective surface of the whole optical system for higher energies. The X-ray optical system composed of modules with thin reflection foils according to this invention has another advantage in that the proposed geometric layout results in a more effective aperture of the X-ray optical system. The proposed layout of the X-ray optical system can be used both for the focusing of X-ray radiation from infinity to point (astrophysical application) and the focusing and illustration of X-ray radiation from point to point (laboratory application). Proposed solution can be modified by adaptive and/or active elements.

BRIEF DESCRIPTION OF DRAWINGS

[0010] Fig. 1 represents the schematics of modules with square aperture according to the Schmidt & Angel layout; Fig. 2 is the schematics of passage of X-rays through the optical system; Fig. 3 represents the segment diagram; Fig 4 is the schematics of X-ray optical system composed of segments; and Fig. 5 represents the schematics of X-ray optical system composed of segments, where the dead zone is filled with this rotationally symmetric reflection foils, which have the common optical axis with the system.

MADE FOR CARRYING OUT THE INVENTION

Embodiment 1:

[0011] X-ray optical system 3 is based on the total reflection. Basic building block of the X-ray optical system 3 is module 1 with square aperture. Individual modules 1 of the proposed optical system 3 are type Schmidt (2D). In the Schmidt layout the module 1 is composed of two sub-modules, in one of which are foils laid out vertically and in the other one horizontally and a single reflection of the X-ray in both sub-modules takes place, as shown in Fig, 2, i.e. the X-ray is reflected twice in each optical system. Thin reflection foils cover with the greatest possible effectiveness the spatial field, i.e. where one foil is ended above the optical axis 4 of the optical system 3, there the other foil begins, as shown in Fig. 2 The reflection foil is a substrate with low surface roughness, enabling the reflection of X-ray radiation. Planar, aspherical curved foils shall be used for the illustrating optical system 3 with short focal length. Reflection planar foils, bilaterally reflecting X-ray radiation with the equally spread out reflection foils throughout the optical system 3, shall be used for the wide-angle illustrating optical system 3. The proposed geometrical layout of the X-ray optical system 3 shall be applied for focusing of X-ray radiation from infinity to point for the astrophysical application and for focusing of X-ray radiation from point to point for the laboratory applications.

Embodiment 2 :

[0012] Modules 1 are laid out in segment 2, and the diagonals of all the modules 1 in segment 2 are always in parallel with symmetry axis 5 of segment 2. Modules 1 are laid out in the square network in a rectangular way so that the spatial covering of the field is as effective as possible. The X-ray optical system 3 is composed of 8 segments 2 according to Fig. 4. Segments 2 are laid out so that they effectively cover the circular aperture of the X-ray optical system 3. All symmetry axes 5 of segments 2 always intersect the optical axis 4 of optical system 3.

Embodiment 3:

[0013] Center of the proposed X-ray optical system 3 may be modified according to Fig. 5. Dead zone is filled with thin, rotationally symmetric foils 7 of parabolic shape, where only one reflection takes place and the effective surface of the whole optical system 3 is thus increased for higher energies. This modification is suitable for an illustration from infinity to point.

Embodiment 4 :

[0014] Center of the proposed X-ray optical system 3 can be modified according to Fig. 5. Dead zone is filled with thin, rotationally symmetric foils 7 of elliptic shape, where only one reflection takes place and the effective surface of the whole optical system 3 is thus increased for higher energies. This modification is suitable for an illustration from point to point.

APPLICATION OF THE INVENTION

[0015] The proposed X-ray optical system 3 can be utilized as a condensor of EUV/X-ray radiation for lithography. EUV/X-ray lithography is used for the industrial production of chips. The whole X-ray optical system 3 can rotate around the optical axis 4 of the optical system 3and thus increases the band homogeneity.

[0016] The proposed X-ray optical system 3 may be utilized for the focusing of particles, e.g. neutrons and electrons.

[0017] The proposed X-ray optical system 3 may be utilized for an increase of the effectiveness of fluorescent X-ray analysis.

List of related signs

[0018] 

1 - module

2 - segment

3 - optical system

4 - optical axis of the optical system

5 - symmetry axis of the segment

6 - dead zone

7 - thin, rotationally symmetric, central reflection foil

Claims

1. X-ray optical system, composed from modules, wherein the optical system (3) is composed from minimum 5 segments (2), each segment (2) is assembled from minimum one module (1) and the diagonals of all modules (1) in each segment (2) are always in parallel with a symmetry axis (5) of the segment (2), and the segment (2) is a sector with a central angle from 18° to 72°, the narrowest part of which being a dead zone (6);
characterised in that
each module (1) is composed of two sub-modules, in one of which are foils laid out vertically and in the other one horizontally and thus adapted so that a single reflection of the X-ray in both sub-modules takes place, i.e. the X-ray is reflected twice in each optical system; the modules comprise thin reflection foils, and planar, aspherical curved foils are used for the x-ray optical system.

2. The X-ray optical system according to claim 1, distinguished by that the dead zone (6) is filled with thin, rotationally symmetric foils laid out in another geometric layout so that a common focus of the whole optical system (3) is formed.

3. The X-ray optical system according to claim 1, distinguished by that individual segments (2) are laid out so that the aperture of the X-ray optical system (3) approaches the circular aperture and the symmetry axis (5) of segment (2) always intersects the optical axis (4) of the X-ray optical system (3).

Ansprüche

1. Röntgenoptisches System, bestehend aus Modulen, wobei das optische System (3) aus mindestens 5 Segmenten (2) besteht, wobei jedes Segment (2) aus mindestens einem Modul (1) zusammengebaut ist und die Diagonalen aller Module (1) in jedem Segment (2) immer parallel zu einer Symmetrieachse (5) des Segments (2) verlaufen und das Segment (2) ein Sektor mit einem Zentriwinkel von 18° bis 72° ist, wobei der engste Teil davon eine Totzone (6) ist;
dadurch gekennzeichnet, dass
jedes Modul (1) aus zwei Untermodulen besteht, wobei in einem von diesen Folien vertikal und in dem anderen horizontal ausgelegt und somit derart ausgebildet sind, dass eine einzelne Reflexion der Röntgenstrahlen in beiden Untermodulen stattfindet, d. h., die Röntgenstrahlen werden in jedem optischen System zweimal reflektiert; wobei die Module dünne Reflexionsfolien umfassen und ebene, asphärisch gekrümmte Folien für das röntgenoptische System verwendet werden.

2. Röntgenoptisches System nach Anspruch 1, dadurch gekennzeichnet, dass die Totzone (6) mit dünnen, rotationssymmetrischen Folien gefüllt ist, die derart in einer anderen geometrischen Anordnung ausgelegt sind, dass ein gemeinsamer Brennpunkt des gesamten optischen Systems (3) ausgebildet wird.

3. Röntgenoptisches System nach Anspruch 1, dadurch gekennzeichnet, dass einzelne Segmente (2) derart ausgelegt sind, dass sich die Öffnung des röntgenoptischen Systems (3) der kreisförmigen Öffnung nähert und die Symmetrieachse (5) des Segments (2) immer die optische Achse (4) des röntgenoptischen Systems (3) schneidet.

Revendications

1. Système optique à rayons X, composé de modules, dans lesquels le système optique (3) est composé de 5 segments (2) minimum, chaque segment (2) est assemblé au minimum à partir d'un module (1) et les diagonales de tous les modules (1) dans chaque segment (2) sont toujours parallèles à un axe de symétrie (5) du segment (2), et le segment (2) est un secteur avec un angle central compris entre 18° et 72°, la partie la plus étroite de ce dernier étant une zone morte (6) ;
caractérisé en ce que
chaque module (1) est composé de deux sous-modules, dans l'un desquels des feuilles sont disposées verticalement et dans l'autre une feuille est disposée horizontalement et par conséquent adaptée à ce qu'il y ait une seule réflexion du rayon X dans les deux sous-modules, c'est-à-dire que le rayon est reflété deux fois dans chaque système optique : les modules comprennent de fines feuilles de réflexion et des feuilles incurvées, asphériques et planaires sont utilisées pour le système optique à rayons X.

2. Le système optique à rayon X selon la revendication 1, caractérisé en ce que la zone morte (6) est remplie de fines feuilles à rotation symétrique disposées dans une autre disposition géométrique de manière à former une visée commune de l'ensemble du système optique (3).

3. Le système optique à rayon X selon la revendication 1, caractérisé en ce que les segments individuels (2) sont disposés de sorte que l'ouverture du système optique à rayon X (3) approche l'ouverture circulaire et que l'axe de symétrie (5) du segment (2) croise toujours l'axe optique (4) du système optique à rayon X (3).

Drawing