Claims
- 1. A method of surface preparation of a chemically etched and cleaned niobium surface to produce a high quantum efficiency material comprising:
a. polishing the niobium surface to remove coarse scratches; b. polishing the niobium surface to remove fine scratches; c. rinsing the niobium surface; d. cleaning the niobium surface to remove polishing material; e. introducing the niobium surfaces into a vacuum chamber and pumping the chamber until background pressure is low; f. baking the vacuum chamber; and g. irradiating the niobium surface with a laser.
- 2. The method of claim 1 wherein the polishing of the niobium surface to remove the coarse scratches is by
a. using abrasive paper on a polisher where the abrasive paper contains grit of about 800 grit size.
- 3. The method of claim 1 wherein the polishing of the niobium surface to remove coarse scratches is by
a. using abrasive paper on a polisher where the abrasive paper contains grit of about 800 grit size and a fluid polishing extender; and b. mounting the niobium surface on a mechanical chuck to hold the niobium surface in a three point design, whereby the three points are adjusted such that all three surfaces are accurately leveled.
- 4. The method of claim 1 wherein the niobium surface is polished to remove fine scratches by
a. using a polishing cloth affixed to a platen; b. applying polishing compound to the polishing cloth; and c. rotating the polishing cloth across the niobium surface.
- 5. The method of claim 4 wherein the polishing compound is a diamond suspension polishing compound.
- 6. The method of claim 4 wherein the platen is rotating at a speed of about 120 rpm and a pressure of about 3 pounds for about 90 seconds.
- 7. The method of claim 1 wherein the niobium surface is rinsed with Hexane.
- 8. The method of claim 5 wherein the suspension is 9 micron suspension.
- 9. The method of claim 8 further comprising:
a. rinsing the niobium surface; b. applying 6 micron suspension to the polishing cloth on a clean platen; and c. rotating the polishing cloth across the niobium surface.
- 10. The method of claim 9 further comprising:
a. rinsing the niobium surface; b. applying 1 micron suspension to the polishing cloth; and c. rotating the polishing cloth across the niobium surface.
- 11. The method of claim 9 wherein the platen is rotating at a speed of about 120 rpm and a pressure of about 3 pounds for about 90 seconds.
- 12. The method of claim 10 wherein the platen is rotating at a speed of about 120 rpm and a pressure of about 3 pounds for about 60 seconds.
- 13. The method of claim 1 wherein the niobium surface is cleaned by introducing the niobium surface to a Hexane bath in an ultrasonic cleaner to remove polishing material.
- 14. The method of claim 13 wherein the niobium is in the Hexane bath for at least 20 minutes.
- 15. The method of claim 1 further comprising after step(d) blowing the niobium surface with high purity nitrogen.
- 16. The method of claim 1 wherein the chamber background pressure is between 10−7 Torr and 10−8 Torr.
- 17. The method of claim 1 wherein the chamber is baked at about 100° C. for between 8 to 12 hours.
- 18. The method of claim 1 wherein the niobium:
a. is irradiated with the laser for about 45 minutes; b. the laser density is approximately equal to 0.6 mJ per 1 mm diameter; c. the laser wavelength is about 266 nm; and d. the laser pulse duration is about 12 ps.
- 19. The method of claim 18 further comprising:
a. adjusting laser energy and laser spot size to yield the high quantum efficiency without damaging the niobium surface.
- 20. A method of surface preparation of a chemically etched and cleaned niobium surface to produce superconducting material comprising:
a. polishing the niobium surface to remove coarse scratches; b. polishing the niobium surface to remove fine scratches by using a polishing cloth affixed to a platen; applying a diamond polishing compound to the polishing cloth; rotating the polishing cloth across the niobium surface; c. rinsing the niobium surface with Hexane; d. cleaning the niobium surface to remove polishing material; e. blowing the niobium surface with high purity nitrogen; f. cleanly transferring the niobium surface into a vacuum chamber and pumping the chamber until background pressure is between 10−7 Torr and 10−8 Torr; g. baking the vacuum chamber at about 100° C. for between 8 to 12 hours; and h. irradiating the niobium surface with a laser.
- 21. Further comprises repeating step (b) with a 1 micron diamond polishing compound.
Government Interests
[0001] This invention was made with Government support under contract number DE-AC0298CH10886, awarded by the U.S. Department of Energy. The Government has certain rights in the invention.