Target assembly with electron and photon windows
An X-ray target assembly includes a substrate, a target supported by the substrate adapted to generate X-rays when impinged by an electron beam, and an enclosure over the target providing a volume for the target. The enclosure is made of a material substantially transparent to electrons. The volume is substantially vacuum or filled with an inert gas.
1. A method of making an X-ray target assembly comprising:
providing a substrate;
disposing a target over the substrate; and
disposing an enclosure over the target, said enclosure and at least a portion of the substrate forming a hermetically sealed volume of substantially no oxygen for the target.
2. The method of claim 1 wherein the enclosure is disposed over the target by a brazing operation in a vacuum.
3. The method of claim 1 wherein the enclosure is disposed over the target by a brazing operation in an inert gas.
4. The method of claim 1 further comprising disposing an additional enclosure over a portion of the substrate under the target forming an additional hermetically sealed volume of substantially no oxygen for the target.
5. The method of claim 4 wherein the additional enclosure is disposed under the target by a brazing operation in hydrogen.
6. The method of claim 4 wherein the additional enclosure is disposed under the target by a brazing operation in a vacuum or an inert gas.
7. The method of claim 1 wherein the substrate is provided with a recess, and said target is disposed in the recess.
8. A method of generating X-rays comprising:
providing a system comprising an envelope of substantially vacuum, an accelerator inside the envelope operable to produce electron beams, and a target assembly outside of the envelope, said target assembly comprising a substrate and a target supported by the substrate adapted to generate X-rays when impinged by an electron beam; and
producing an electron beam from the accelerator to the target to generate X-rays.
9. The method of claim 8 further comprising directing an inert gas across at least a portion of the target during operation.
10. The method of claim 8 wherein the system further comprises an additional envelope enclosing at least a portion of the target.
11. The method of claim 10 further comprising purging the additional envelope using a vacuum pump.
12. The method of claim 10 further comprising backfilling the additional envelope with an inert gas.
13. The method of claim 8 wherein the target is provided with a layer comprising an oxidation resistant material.
14. The method of claim 8 wherein the target is provided with an enclosure over the target, said enclosure and at least a portion of the substrate forming a sealed volume for the target.
15. An X-ray target assembly comprising:
a substrate; and
a target supported by the substrate adapted to generate X-rays when impinged by an electron beam, wherein said target comprises a first surface and a second surface opposite to the first surface, said first surface being supported by the substrate, and said second surface having a coating of an oxidation resistent material adapted to protect the target from oxidation when in operation.