Corrosion-resistant, strong x-ray window
The invention is an x-ray window with a stack of thin film layers including aluminum layer(s), corrosion-barrier layer(s), and/or polymer layer(s). Aluminum layer(s) can provide improved gas impermeability. Polymer layer(s) can increase structural strength. The x-ray window can be substantially transmissive to x-rays but also substantially block visible light and infrared light. The x-ray window can have minimal deflection.
1. An x-ray window comprising:
a. a stack of thin film layers including a first aluminum layer, a second aluminum layer, a polyimide layer, and a corrosion-barrier layer;
b. the corrosion-barrier layer comprises a material selected from the list consisting of amorphous carbon and hexamethyldisilazane;
c. an order of the stack of thin film layers is the corrosion-barrier layer, the first aluminum layer, the polyimide layer, then the second aluminum layer;
d. an enclosure having a hollow center and an opening;
e. the stack of thin film layers is hermetically sealed to the opening of the enclosure;
f. the corrosion-barrier layer is disposed as the farthest layer away from the hollow center;
g. the stack of thin film layers having:
i. a transmissivity of greater than 60% for x-rays having an energy of 1.74 keV;
ii. a transmissivity of less than 10% for visible light at a wavelength of 550 nanometers; and
iii. a transmissivity of less than 10% for infrared light at a wavelength of 800 nanometers.
2. The x-ray window of claim 1 , wherein the stack of thin film layers have a deflection distance of less than 300 micrometers with one atmosphere differential pressure across the stack of thin film layers.
3. The x-ray window of claim 1 , wherein the stack of thin film layers have:
a. a deflection distance of less than 200 micrometers with one atmosphere differential pressure across the stack of thin film layers;
b. a transmissivity of greater than 70% for an x-ray energy of 1.74 keV;
c. a transmissivity of less than 3% for visible light at a wavelength of 550 nanometers; and
d. a transmissivity of less than 4% for infrared light at a wavelength of 800 nanometers.
4. The x-ray window of claim 1 , wherein the enclosure comprises titanium.
5. The x-ray window of claim 1 , wherein:
a. the polyimide layer has a thickness of between 150 to 400 nanometers;
b. the first aluminum layer has a thickness of between 10 to 30 nanometers;
c. the second aluminum layer has a thickness of between 10 to 30 nanometers; and
d. the corrosion-barrier layer has a thickness of between 5 to 25 nanometers.
6. An x-ray window comprising:
a. a stack of thin film layers including an aluminum layer, a polymer layer, and a corrosion-barrier layer;
b. the corrosion-barrier layer comprises a material selected from the list consisting of amorphous carbon and hexamethyldisilazane;
c. the stack of thin film layers having:
i. a transmissivity of greater than 60% for x-rays having an energy of 1.74 keV;
ii. a transmissivity of less than 10% for visible light at a wavelength of 550 nanometers; and
iii. a transmissivity of less than 10% for infrared light at a wavelength of 800 nanometers.
7. The x-ray window of claim 6 , wherein the stack of thin film layers have a deflection distance of less than 300 micrometers with one atmosphere differential pressure across the stack of thin film layers.
8. The x-ray window of claim 6 , wherein the stack of thin film layers have:
a. a deflection distance of less than 200 micrometers with one atmosphere differential pressure across the stack of thin film layers;
b. a transmissivity of greater than 70% for an x-ray energy of 1.74 keV;
c. a transmissivity of less than 3% for visible light at a wavelength of 550 nanometers; and
d. a transmissivity of less than 4% for infrared light at a wavelength of 800 nanometers.
9. The x-ray window of claim 6 , wherein the corrosion-barrier layer comprises amorphous carbon with hybridization of carbon that is:
a. less than 25% sp3 hybridization; and
b. greater than 75% sp2 hybridization.
10. The x-ray window of claim 6 , wherein the corrosion-barrier layer comprises hydrogenated amorphous carbon with an atomic percent of hydrogen between 1% and 10%.
11. The x-ray window of claim 6 , wherein the polymer is a polyimide.
12. The x-ray window of claim 6 , wherein:
a. a mass percent of aluminum in the aluminum layer is at least 95%;
b. a mass percent of polymer in the polymer layer is at least 95%;
c. a mass percent of carbon and hydrogen in the corrosion-barrier layer is at least 95%.
13. The x-ray window of claim 6 , wherein an order of the layers in the stack of thin film layers is the polymer layer, the aluminum layer, then the corrosion-barrier layer.
14. The x-ray window of claim 6 , wherein:
a. the polymer layer has a thickness of between 150 to 400 nanometers;
b. the corrosion-barrier layer has a thickness of between 5 to 25 nanometers; and
c. the aluminum layer has a thickness of between 10 to 30 nanometers.
15. The x-ray window of claim 6 , further comprising an enclosure having a hollow center and an opening, the enclosure comprising titanium, and wherein the stack of thin film layers is hermetically sealed to the opening of the enclosure.
16. The x-ray window of claim 15 , wherein the corrosion-barrier layer is the farthest layer away from the hollow center.
17. The x-ray window of claim 15 , wherein:
a. the aluminum layer comprises a first aluminum layer and a second aluminum layer; and
b. an order of the stack of thin film layers is the first aluminum layer, the polymer layer, the second aluminum layer, then the corrosion-barrier layer.
18. An x-ray window comprising:
a. a stack of thin film layers including an aluminum layer disposed between a first corrosion-barrier layer and a second corrosion-barrier layer;
b. the first corrosion-barrier layer and the second corrosion-barrier layer comprise a material selected from the list consisting of amorphous carbon and hexamethyldisilazane;
c. the stack of thin film layers having:
i. a transmissivity of greater than 60% for an x-ray energy of 1.74 keV;
ii. a transmissivity of less than 10% for visible light at a wavelength of 550 nanometers; and
iii. a transmissivity of less than 10% for infrared light at a wavelength of 800 nanometers.
19. The x-ray window of claim 18 , wherein the stack of thin film layers have:
a. a deflection distance of less than 200 micrometers with one atmosphere differential pressure across the stack of thin film layers;
b. a transmissivity of greater than 70% for an x-ray energy of 1.74 key;
c. a transmissivity of less than 3% for visible light at a wavelength of 550 nanometers; and
d. a transmissivity of less than 4% for infrared light at a wavelength of 800 nanometers.
20. The x-ray window of claim 18 , wherein:
a. the first corrosion-barrier layer has a thickness of between 1 to 25 nanometers;
b. the aluminum layer has a thickness of between 10 to 60 nanometers; and
c. the second corrosion-barrier layer has a thickness of between 1 to 25 nanometers.