1. Motor vehicle outer tank for a cryogenic fuel which is situated in an inner tank which is positioned within the outer tank wherein the outer tank is of flat design, and in that planar side walls of the outer tank are at least partially of sandwich design or are reinforced with sandwich plates.
2. Outer tank according to claim 1, wherein a sandwich plate which is provided with an upper belt and a lower belt is mounted on a planar side wall of the outer tank.
3. Outer tank according to claim 1, wherein a sandwich plate with an upper belt but without a lower belt is adhesively bonded to a planar side wall of the outer tank, with the side wall of the outer tank serving as a lower belt and being part of the sandwich plate.
4. Outer tank according to claim 1, wherein at least the upper belt of the sandwich plate is connected with its edge to the side wall of the outer tank by means of a weld seam.
5. Outer tank according to claim 1, wherein the side walls of the outer tank are produced in a deformation process, and the sandwich plate projects up to a hardened edge region of a side wall and is welded to the latter there.
6. Outer tank according to claim 1, wherein a side wall is provided in the peripheral region with an outwardly aligned edge bead or arched portion and the sandwich plate extends at least up to said edge bead and is welded there at least with its upper belt to the side wall of the outer tank, with the upper belt of the sandwich plate lying in a plane with the edge bead, that is to say the highest region of the latter.
7. Outer tank according to claim 1 wherein the sandwich plate extends up to a side panel which is adjacent to the outer tank, and said sandwich plate is fixedly connected to said side panel.
8. Outer tank according to claim 1, wherein T-bolts are fastened to that side wall of the outer tank which is reinforced with the sandwich plate, which T-bolts extend perpendicular to the side wall and extend through the sandwich plate, and in that wherein the sandwich plate is secured on the outer tank by means of a screw connection on the T-bolt.
9. Outer tank according to claim 1, characterized in that wherein the weld seam of the connection of the sandwich plate to the outer tank is formed as a stepped weld seam.
10. Outer tank according to claim 1, wherein the outer tank has a height of between 100 and 500 mm.
11. Outer tank according to claim 1, wherein the sandwich plate has a thickness of between 5 and 20 mm.
12. Outer tank according to claim 1 wherein the sandwich plate has a central region with a support core which is compressed in relation to the edge region.
13. Outer tank according to claim 1, wherein the sandwich plate, in its peripheral edge region, decreases in height to the peripheral edge, and no support core is provided in said peripheral region.
14. Outer tank according to claim 1, wherein the area of contact of the sandwich plate with the side wall of the outer tank has ventilation ducts for promoting adhesive curing and degassing, which ventilation ducts are formed by ducts in the adhesive layer andor by ribs on the side wall of the outer tank andor by holes in the sandwich plate.
15. Outer tank according to claim 1, wherein the sandwich plate is guided up to an auxiliary system capsule, which is arranged adjacent to the outer tank, for tank accessories, and is fixedly connected to the auxiliary system capsule.
16. Outer tank according to claim 1, wherein both the side wall of the outer tank and also the upper and lower belt of the sandwich plate are formed from aluminum or an aluminum alloy.
17. Outer tank according to claim 1, wherein the edge and narrow-side regions of the outer tank do not have any sandwich reinforcement.
18. Tank having an outer tank according to claim 1, wherein the outer tank is self-supporting and the inner tank is not loaded by air pressure forces which act on the outer tank.
19. Outer tank according to claim 1, wherein the outer tank is shaped as a parallelepiped.
20 Outer tank according to claim 1, wherein the sandwich plate is adhesively bonded to the planar side wall of the outer tank.
21. Outer tank according to claim 1, wherein the upper belt and lower belt thereof are connected to the side wall of the outer tank by means of a weld seam.
22. Outer tank according to claim 1, wherein the side walls of the outer tank are produced in a cold working process.
23. Outer tank according to claim 1, wherein the side walls of the outer tank are produced in a deep-drawing process.
24. Outer tank according to claim 1, wherein the sandwich plate projects up to a work-hardened edge region.
25. Outer tank according to claim 1, wherein the sandwich plate extends up to a body panel which is adjacent to the outer tank.
26. Outer tank according to claim 1, wherein the sandwich plate is fixedly connected by screws to said side panel.
27. Outer tank according to claim 1, wherein the outer tank has a height of between 250 and 350 mm and a length of between 700 and 1000 mm.
28. Outer tank according to claim 1, wherein the sandwich plate has a central region with a honeycomb core.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A magnetic lens for generating a magnetic imaging field to focus charged particles emitted from a sample, the lens comprising a central pole piece and an outer pole piece disposed about the central pole piece, wherein the lens comprises at least one magnetic moveable element for movement relative to at least one of the pole pieces, whereby a focal length of the lens is variable by said movement of the at least one magnetic moveable element.
2. A magnetic lens as claimed in claim 1 wherein said movement of the at least one magnetic moveable element changes the magnetic circuit between the pole pieces.
3. A magnetic lens as claimed in claim 1 wherein the central pole piece comprises a magnetic moveable element which comprises a magnetic part which, in a first position, forms at least part of the central pole piece whereby a first magnetic circuit is generated and, in a second position, forms part of the outer pole piece whereby a second magnetic circuit is generated, different from the first magnetic circuit.
4. A magnetic lens as claimed in claim 1 wherein the at least one magnetic moveable element comprises a first magnetic part and a second magnetic part, said first magnetic part and second magnetic part being separated by a non-magnetic part.
5. A magnetic lens as claimed in claim 4 wherein the at least one magnetic moveable element is moveable between at least a first position and a second position, wherein, in the first position it defines a first focal length of the lens and, in the second position it defines a second focal length of the lens.
6. A magnetic lens as claimed in claim 1 wherein the central pole piece and the outer pole piece are symmetrical about an axis of the lens and the outer pole piece is annularly disposed about the central pole piece and co-axial therewith thereby defining an annular space therebetween, the lens further comprising an energizing means disposed in the annular space.
7. A magnetic lens as claimed in claim 1 wherein the central pole piece comprises a body, a moveable element being arranged for movement therein.
8. A magnetic lens as claimed in claim 7 wherein the body has a through-bore for accommodating therein the moveable element.
9. A magnetic lens as claimed in claim 7 wherein the moveable element is moveable between at least a first position and a second position with respect to the body of the central pole piece, wherein, in the first position, the moveable element is positioned with respect to the body whereby the first and second magnetic parts of the moveable element are in connection with the body such that the first and second magnetic parts form part of the central pole piece thereby defining a first focal length of the lens and, in the second position, the moveable element is positioned with respect to the body whereby the first magnetic part of the moveable element is in connection with the body such that the first magnetic part forms part of the central pole piece and the second magnetic part of the moveable element is in connection with the outer pole piece such that the second magnetic part forms part of the outer pole piece, thereby defining a second focal length of the lens.
10. A magnetic lens as claimed in claim 1 wherein the outer pole piece has a sample facing end which extends inward toward the central pole piece, wherein said end has an internal diameter which decreases in the direction of the sample.
11. A magnetic lens as claimed in claim 4 wherein the first magnetic part comprises a magnetic elongate member.
12. A magnetic lens as claimed in claim 4 wherein the first magnetic part has a sample facing end which has an external diameter which decreases in the direction of the sample.
13. A magnetic lens as claimed in claim 4 wherein the second magnetic part comprises a magnetic annular member which is disposed about the first magnetic part.
14. A magnetic lens as claimed in claim 13 wherein the second magnetic part has an outer surface profiled for engagement with a complementarily profiled inner surface of the outer pole piece.
15. A magnetic lens as claimed in claim 4 wherein the second magnetic part has a maximum external diameter which is greater than the minimum internal diameter of the outer pole piece.
16. A magnetic lens as claimed in claim 1 wherein, in the first position, the central pole piece does not extend out of the lens beyond the outer pole piece and, in the second position, the central pole piece extends out of the lens beyond the outer pole piece.
17. A magnetic lens as claimed in claim 1 wherein the outer pole piece comprises a magnetic moveable element which comprises a magnetic part which, in a first position, forms at least part of the outer pole piece whereby a first magnetic circuit is generated and, in a second position, forms part of the central pole piece whereby a second magnetic circuit is generated, different from the first magnetic circuit.
18. A magnetic lens as claimed in claim 1 wherein the lens provides at least two different magnifications.
19. A magnetic lens as claimed in claim 18 wherein the lens provides at least three different magnifications.
20. A method of focusing charged particles emitted from a sample comprising:
providing a magnetic lens in proximity to the sample for generating a magnetic imaging field to focus the charged particles;
energizing the magnetic lens to generate the magnetic imaging field;
causing charged particles to be emitted from the sample; and
focusing at least some of the charged particles emitted from the sample to produce a charged particle image of the sample;
wherein the magnetic lens comprises a central pole piece and an outer pole piece disposed about the central pole piece, wherein the lens further comprises at least one magnetic moveable element for movement relative to at least one of the pole pieces, whereby a focal length of the lens is variable by said movement of the at least one magnetic moveable element.
21. A method as claimed in claim 20 comprising energizing the lens when at least one moveable element of the lens is in a first position thereby defining a first focal length of the lens and providing the lens in proximity to the sample at a first working distance and energizing the lens when the moveable element is in a second position thereby defining a second focal length of the lens and providing the lens in proximity to the sample at a second working distance.
22. An analyzer for analyzing a selected area of the surface region of a sample comprising: a sample holder for holding the sample; a source of radiation for causing the emission of charged particles from a sample placed on the sample holder; a magnetic lens for focusing at least some of the charged particles emitted from the sample; and analyzing means for analyzing the energy of the focused charged particles emitted from the sample, wherein the magnetic lens comprises a central pole piece and an outer pole piece disposed about the central pole piece, wherein the lens comprises at least one magnetic moveable element for movement relative to at least one of the pole pieces, whereby a focal length of the lens is variable by said movement of the at least one magnetic moveable element.
23. The method of claim 20, wherein the step of causing charged particles to be emitted from the sample includes irradiating a surface region of the sample with radiation thereby causing the emission of charged particles from the surface region and further comprising a step of analyzing the energy of the focused charged particles.
24. The analyzer of claim 22, wherein the source of radiation includes a source of x-ray or ultraviolet radiation for causing the emission of photoelectrons from the sample, and wherein the analyzer means includes and electron analyzing means for analyzing the energy of the focused photoelectrons emitted from the sample.