Graphite x-ray window
The x-ray windows herein can have low gas permeability, low outgassing, high strength, low visible and infrared light transmission, high x-ray flux, low atomic number materials, corrosion resistance, high reliability, and low-cost. The x-ray window can include a film 11 with a polymer layer 22 and a graphite layer 21 . The film 11 can consist essentially of graphite and polymer. Most of the film 11 can be the graphite layer 21 . The polymer layer 22 can be a small portion of the film 11.
1. A method of making an x-ray window, the method comprising:
obtaining a graphite layer on a flexible substrate;
spin coating a polymer precursor on the graphite layer;
baking the graphite layer and the polymer precursor to form a polymer layer on the graphite layer; and
removing the flexible substrate from the graphite layer.
2. The method of claim 1 , further comprising, after baking the graphite layer and the polymer precursor, laser cutting the polymer layer and the graphite layer to form multiple x-ray windows.
3. The method of claim 2 , wherein the polymer layer and the graphite layer are cut together in a single step by a laser.
4. The method of claim 1 , wherein removing the flexible substrate from the graphite layer includes manually peeling the flexible substrate with plastic-tip tweezers.
5. The method of claim 1 , wherein the polymer precursor includes an imide dissolved in N-methyl-2-pyrrolidone.
6. The method of claim 5 , wherein a volume of the n-methyl-2-pyrrolidone divided by a volume of the imide is ≥1.5 and ≤6.
7. The method of claim 5 , wherein the imide is biphenyldianhydride/1,4 phenylenediamine.
8. The method of claim 5 , wherein baking the graphite layer and the polymer precursor forms the imide into a polyimide in the polymer layer.
9. The method of claim 1 , wherein the flexible substrate includes polyethylene terephthalate.
10. The method of claim 1 , wherein:
the spin coating step includes spin coating with the flexible substrate facing a spin coat tool and the graphite layer facing away from the spin coat tool;
the baking step includes baking the flexible substrate; and
the method is performed in the order listed in claim 1 .
11. The method of claim 10 , wherein the flexible substrate adjoins a silicon spin plate on the spin coat tool and the spin plate comprises silicon.
12. The method of claim 1 , wherein a thickness of the flexible substrate divided by a thickness of the graphite layer ≥2 and ≤20.
13. The method of claim 1 , further comprising, after baking and before removing the flexible substrate from the graphite layer, laser cutting the polymer layer, the graphite layer, and the flexible substrate together to form multiple x-ray windows.
14. The method of claim 1 , wherein the flexible substrate includes vinyl.
15. A method of making an x-ray window, the method comprising:
obtaining a graphite layer on a flexible substrate;
spin coating a polymer precursor on the graphite layer, wherein the polymer precursor includes biphenyldianhydride/1,4 phenylenediamine, dissolved in N-methyl-2-pyrrolidone and the polymer layer includes polyimide;
baking the graphite layer and the polymer precursor to form a polymer layer including polyimide on the graphite layer; and
laser cutting the polymer layer and the graphite layer to form multiple x-ray windows.
16. The method of claim 15 , wherein the polymer layer and the graphite layer are cut together in a single step by a laser.
17. The method of claim 15 , wherein a volume of the n-methyl-2-pyrrolidone divided by a volume of the biphenyldianhydride/1,4 phenylenediamine is ≥1.5 and ≤6.
18. A method of making an x-ray window, the method comprising the following steps in the following order:
obtaining a graphite layer on a flexible substrate, and the flexible substrate includes polyethylene terephthalate;
spin coating a polymer precursor on the graphite layer with the flexible substrate facing a spin coat tool and the graphite layer facing away from the spin coat tool; and
baking the graphite layer and the polymer precursor to form a polymer layer on the graphite layer.
19. The method of claim 18 , wherein the flexible substrate adjoins a silicon spin plate on the spin coat tool and the spin plate comprises silicon.
20. The method of claim 18 , wherein a thickness of the flexible substrate divided by a thickness of the graphite layer ≥2 and ≤20.