X-ray microscope with microfocus source and Wolter condenser
An x-ray microscope uses a microfocus x-ray source with a focus spot of less than 10 micrometers and a Wolter condenser having a magnification of about four or more for concentrating x-rays from the source onto a sample. A detector is provided for detecting the x-rays after interaction with the sample, and an x-ray objective is used to form an image of the sample on the detector. The use of the Wolter optic addresses a problem with microfocus sources that arise when the size of the focal spot that must then be imaged onto the sample with the condenser is smaller than the field of view.
1. An x-ray microscope, comprising:
a microfocus x-ray source with a focus spot of less than 10 micrometers;
a Wolter condenser having a magnification of about two or more for magnifying and imaging the focus spot from the source onto a sample and concentrating x-rays from the source onto the sample;
a detector for detecting the x-rays after interaction with the sample; and
an x-ray objective for forming an image of the sample on the detector.
2. An x-ray microscope as claimed in claim 1 , wherein the focus spot of the x-ray source is 4-7 micrometers in diameter.
3. An x-ray microscope as claimed in claim 1 , wherein the focus spot of the x-ray source is about 1 micrometer or less in diameter.
4. An x-ray microscope as claimed in claim 1 , wherein the Wolter condenser has a magnification of four or more.
5. An x-ray microscope as claimed in claim 1 , wherein the Wolter condenser comprises a glass capillary tube.
6. An x-ray microscope as claimed in claim 5 , wherein the glass capillary tube comprises an inner metal coating.
7. An x-ray microscope as claimed in claim 5 , wherein the glass capillary tube comprises a thin film coating comprising alternating layers of different elements.
8. An x-ray microscope as claimed in claim 1 , wherein the Wolter condenser comprises two pieces of glass capillary tube bonded together.
9. An x-ray microscope, comprising:
a microfocus x-ray source with a focus spot of less than 10 micrometers;
a Wolter condenser having a magnification of about two or more for concentrating x-rays from the source onto a sample;
a detector for detecting the x-rays after interaction with the sample; and
an x-ray objective for forming an image of the sample on the detector;
wherein a length of an ellipsoidal segment of the condenser is 1.5 or more times longer than an hyperbolic segment.
10. An x-ray microscope as claimed in claim 1 , wherein the x-rays have an energy of 1 or more kilo electron-volts.
11. An x-ray microscope as claimed in claim 1 , wherein the x-ray objective is a zone plate.
12. An x-ray microscope as claimed in claim 1 , wherein the x-ray objective is a compound refractive lens.
13. An x-ray microscope as claimed in claim 1 , wherein the x-ray objective is a Wolter mirror.
14. An x-ray microscope as claimed in claim 1 , being arranged in phase contrast configuration with a phase ring to image the phase shift through the sample.