Search

US-12626880-B2 - X-ray window with stack of layers

US12626880B2US 12626880 B2US12626880 B2US 12626880B2US-12626880-B2

Abstract

A mounted x-ray window 10 and 20 can include an x-ray window 18 mounted on the flange 11 f of a housing 11 . The x-ray window 18 can include the following layers: a top strong layer 17 , a stress-relief layer 16 , a bottom strong layer 15 , an adhesive layer 14 then a support ring 13 . These layers can have a material composition and thickness for optimizing x-ray window 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.

Inventors

  • Ghazaleh Allaedini

Assignees

  • MOXTEK, INC.

Dates

Publication Date
20260512
Application Date
20240725

Claims (20)

  1. 1 . A mounted x-ray window comprising: a housing including a flange encircling an aperture; an x-ray window mounted on the flange and spanning and covering the aperture; the x-ray window including the following layers in the following order: a top strong layer, a stress-relief layer, a bottom strong layer, an adhesive layer, then a support ring, the support ring located closest to the flange than any other layer of the x-ray window; the support ring includes a hole that is aligned with the aperture; the top strong layer includes boron, the stress-relief layer includes polyimide, the bottom strong layer includes boron, and the adhesive layer includes polyimide; a bonding ring is sandwiched between the support ring and the flange, the bonding ring sealing the support ring to the flange; and wherein the support ring includes: ≥24 mass percent and ≤34 mass percent nickel; ≥7 mass percent and ≤27 mass percent cobalt; ≥43 mass percent and ≤64 mass percent iron; and a sum of the above mass percentages plus mass percentages of trace elements equal 100 mass percent.
  2. 2 . The mounted x-ray window of claim 1 , wherein the trace elements include carbon, manganese, and silicon.
  3. 3 . A mounted x-ray window comprising: a housing including a flange encircling an aperture; an x-ray window mounted on the flange and spanning and covering the aperture; the x-ray window including the following layers in the following order: a top strong layer, a stress-relief layer, a bottom strong layer, an adhesive layer, then a support ring; the top strong layer located farther from the flange than any other layer of the x-ray window; the top strong layer and the bottom strong layer each include boron; the top strong layer and the bottom strong layer each include hydrogen, carbon, aluminum, nitrogen, or combinations thereof; the stress-relief layer and the adhesive layer each include a polymer; the support ring includes a hole that is aligned with the aperture; a bonding ring between the support ring and the flange, the bonding ring sealing the support ring to the flange; and wherein the support ring includes: ≥24 mass percent and ≤34 mass percent nickel; ≥7 mass percent and ≤27 mass percent cobalt; ≥43 mass percent and ≤64 mass percent iron; and a sum of the above mass percentages plus mass percentages of trace elements in the support ring equal 100 mass percent.
  4. 4 . The mounted x-ray window of claim 3 , wherein the trace elements include carbon, manganese, and silicon.
  5. 5 . The mounted x-ray window of claim 3 , wherein the stress-relief layer and the adhesive layer include at least 95 mass percent of the same polymer.
  6. 6 . The mounted x-ray window of claim 3 , wherein the stress-relief layer and the adhesive layer each include ≥95 mass percent polyimide.
  7. 7 . The mounted x-ray window of claim 3 , wherein the top strong layer and the bottom strong layer each include ≥95 mass percent boron.
  8. 8 . The mounted x-ray window of claim 3 , wherein the top strong layer, the stress-relief layer, the bottom strong layer, and the adhesive layer span the aperture.
  9. 9 . A mounted x-ray window comprising: a housing including a flange encircling an aperture; an x-ray window mounted on the flange and spanning and covering the aperture; the x-ray window including the following layers in the following order: a top strong layer, a stress-relief layer, a bottom strong layer, an adhesive layer, then a support ring; the top strong layer located farther from the flange than any other layer of the x-ray window; the top strong layer and the bottom strong layer each include boron; the top strong layer and the bottom strong layer each include hydrogen, carbon, aluminum, nitrogen, or combinations thereof; the stress-relief layer and the adhesive layer each include a polymer; the support ring includes a hole that is aligned with the aperture; a bonding ring between the support ring and the flange, the bonding ring sealing the support ring to the flange; a thickness of the top strong layer at the aperture is ≥2 and ≤10 times thicker than the stress-relief layer; a thickness of the bottom strong layer at the aperture is ≥2 and ≤10 times thicker than the stress-relief layer; and a thickness of the stress-relief layer at the aperture is ≥1.5 and ≤6 times thicker than the adhesive layer.
  10. 10 . The mounted x-ray window of claim 9 , wherein: the top strong layer and the bottom strong layer each include ≥75 mass percent boron; and the top strong layer and the bottom strong layer each include ≥10 mass percent aluminum.
  11. 11 . The mounted x-ray window of claim 9 , wherein the stress-relief layer and the adhesive layer include at least 95 mass percent of the same polymer.
  12. 12 . The mounted x-ray window of claim 9 , wherein the stress-relief layer and the adhesive layer each include ≥95 mass percent polyimide.
  13. 13 . A mounted x-ray window comprising: a housing including a flange encircling an aperture; an x-ray window mounted on the flange and spanning and covering the aperture; the x-ray window including the following layers in the following order: a top strong layer, a stress-relief layer, a bottom strong layer, an adhesive layer, then a support ring; the top strong layer located farther from the flange than any other layer of the x-ray window; the top strong layer and the bottom strong layer each include boron; the top strong layer and the bottom strong layer each include hydrogen, carbon, aluminum, nitrogen, or combinations thereof; the stress-relief layer and the adhesive layer each include a polymer; the support ring includes a hole that is aligned with the aperture; a bonding ring between the support ring and the flange, the bonding ring sealing the support ring to the flange; a thickness of the top strong layer at the aperture is ≥800 nm and ≤4000 nm; a thickness of the bottom strong layer at the aperture is ≥800 nm and ≤4000 nm; a thickness of the stress-relief layer at the aperture is ≥50 nm and ≤800 nm; and a thickness of the adhesive layer is ≥20 nm and ≤300 nm.
  14. 14 . The mounted x-ray window of claim 13 , wherein a thickness of the top strong layer in the aperture equals a thickness of the bottom strong layer in the aperture.
  15. 15 . The mounted x-ray window of claim 13 , wherein: the top strong layer and the bottom strong layer each include ≥90 mass percent boron; and the top strong layer and the bottom strong layer each include ≥0.05 mass percent hydrogen.
  16. 16 . The mounted x-ray window of claim 13 , wherein: the top strong layer and the bottom strong layer each include ≥70 mass percent boron; and the top strong layer and the bottom strong layer each include ≥15 mass percent carbon.
  17. 17 . The mounted x-ray window of claim 13 , wherein: the top strong layer and the bottom strong layer each include ≥75 mass percent boron; and the top strong layer and the bottom strong layer each include ≥10 mass percent aluminum.
  18. 18 . The mounted x-ray window of claim 13 , wherein: the top strong layer and the bottom strong layer each include ≥35 mass percent boron; and the top strong layer and the bottom strong layer each include ≥45 mass percent nitrogen.
  19. 19 . The mounted x-ray window of claim 13 , wherein the stress-relief layer and the adhesive layer include at least 95 mass percent of the same polymer.
  20. 20 . The mounted x-ray window of claim 13 , wherein the stress-relief layer and the adhesive layer each include ≥95 mass percent polyimide.

Description

CLAIM OF PRIORITY This application claims priority to US Provisional Patent Application Number U.S. 63/578,781, filed on Aug. 25, 2023, which is incorporated herein by reference. FIELD OF THE INVENTION The present application is related to x-ray windows. BACKGROUND X-ray windows are designed to transmit a high percent of x-rays, even low energy x-rays. X-ray windows are used in expensive systems requiring high reliability. High system requirements result in demanding characteristics of the x-ray window. BRIEF DESCRIPTION OF THE DRAWINGS (DRAWINGS MIGHT NOT BE DRAWN TO SCALE) FIG. 1 is a cross-sectional side-view of a mounted x-ray window 10 including an x-ray window 18 bonded to a flange 11f of a housing 11 by a bonding ring 12. The x-ray window 18 can include a top strong layer 17, a stress-relief layer 16, a bottom strong layer 15, an adhesive layer 14, and a support ring 13. FIG. 2 is a top-view of a mounted x-ray window 20, similar to the mounted x-ray window 10, except that the adhesive layer 14 in mounted x-ray window 20 has a ring shape. FIG. 3 is a cross-sectional side-view illustrating a step 30 in a method of making a mounted x-ray window 10 or 20, including applying a stress-relief layer 16 on a wafer 31. FIG. 4 is a cross-sectional side-view illustrating a step 40 in a method of making a mounted x-ray window 10 or 20, including attaching a solid ring 41 on the stress-relief layer 16. Step 40 can follow step 30. FIG. 5 is a cross-sectional side-view illustrating a step 50 in a method of making a mounted x-ray window 10 or 20, including using an acid to release the stress-relief layer 16 from the solid wafer 31 with the solid ring 41 remaining attached to the stress-relief layer 16. Step 50 can follow step 40. FIG. 6 is a cross-sectional side-view illustrating a step 60 in a method of making a mounted x-ray window 10 or 20, including depositing a top strong layer 17 across one side of the stress-relief layer 16 and a bottom strong layer 15 across an opposite side of the stress-relief layer 16. Step 60 can follow step 50. FIG. 7 is a cross-sectional side-view illustrating a step 70 in a method of making a mounted x-ray window 10, including applying an adhesive layer 14 on the bottom strong layer 15. Step 70 can follow step 60. FIG. 8 is a cross-sectional side-view illustrating a step in a method of making a mounted x-ray window 10, including placing a support ring 13 on the adhesive layer 14. The support ring 13 can be aligned with a central opening 42 of the solid ring 41. The support ring 13 can include a hole. Step 80 can follow step 70. FIG. 9 is a cross-sectional side-view illustrating a step 90 in a method of making a mounted x-ray window 10, including cutting around the support ring 13 to form an x-ray window 18. Step 90 can follow step 80. FIG. 10 is a cross-sectional side-view illustrating a step 100 in a method of making a mounted x-ray window 20, including applying an adhesive layer 14 on a support ring 13. Step 100 can follow step 60. FIG. 11 is a cross-sectional side-view illustrating a step 110 in a method of making a mounted x-ray window 20, including placing the support ring 13 and the adhesive layer 14 on the bottom strong layer 15, with the adhesive layer 14 sandwiched between the support ring 13 and the bottom strong layer 15. The support ring 13 and the adhesive layer 14 can be aligned with a central opening 42 of the solid ring 41. Step 110 can follow step 100. FIG. 12 is a cross-sectional side-view illustrating a step 120 in a method of making a mounted x-ray window 20, including placing a drop of polymer 124 on the bottom strong layer 15 within an opening of the adhesive layer 14. Step 120 can follow step 110. FIG. 13 is a cross-sectional side-view illustrating a step 130 in a method of making a mounted x-ray window 20, including cutting around the support ring 13 to form an x-ray window 18. Step 130 can follow step 120. Definitions. The following definitions, including plurals of the same, apply throughout this patent application. As used herein, the terms “on”, “located on”, “located at”, and “located over” mean located directly on or located over with some other solid material between. The terms “located directly on”, “adjoin”, “adjoins”, and “adjoining” mean direct and immediate contact. As used herein, the terms “same as” or “equals” mean exactly the same; the same within normal manufacturing tolerances; or almost exactly the same, such that any deviation from exactly the same would have negligible effect for ordinary use of the device. As used herein, the term “nm” means nanometer(s). As used herein, the term “x-ray tube” is not limited to tubular/cylindrical shaped devices. The term “tube” is used because this is the standard term used for x-ray emitting devices. DETAILED DESCRIPTION Useful characteristics of x-ray windows include low gas permeability, low outgassing, high strength, low visible and infrared light transmission, high x-ray flux, made of low atomic number