Muon drift tube and method of making same

• US 10,381,205 B1
• Filed: 05/04/2018
• Issued: 08/13/2019
• Est. Priority Date: 05/04/2018
• Status: Active Grant

• Current Assignee: Douglas Electrical Components, Inc.
• Original Assignee: Douglas Electrical Components, Inc.
• Inventors: Schwed, Stephen, Douglas, Edward William, Pellegrino, Stephen Diego, Rempel, Christopher
• Primary Examiner(s): Bryant, Michael C
• Application Number:
  US15/971,894
• Time in Patent Office: 466 Days
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01T 1/185 with ionisation chamber arrangements
• CPC Class Codes: H01J 47/001 Details
• CPC Class Codes: H01J 47/005 Gas fillings H01J47/12 takes precedence; Maintaining the desired pressure within the tube
• CPC Class Codes: H01J 47/008 Drift detectors

Abstract

Various configurations of muon drift tubes for use in muon tomography are described and involve aluminum end caps coupled to an aluminum tube, an electrode in each of the end caps, and an anode wire extending between the electrodes. A two-part electrically conductive, gas-sealed, connection is located between an aluminum end cap and the aluminum tube. Methods of making those configurations of muon drift tubes are also described.

Claims

1. A muon drift tube for use in muon tomography comprising:

an aluminum tube having a first end, a second end, and a longitudinal axis;

an aluminum first cap coupled to the first end of the tube;

an aluminum second cap coupled to the second end of the tube;

a first electrode physically coupled to, but electrically isolated from, the first cap;

a second electrode physically coupled to, but electrically isolated from, the second cap;

a conductive wire within the tube extending, along the longitudinal axis, between the first electrode and the second electrode,

wherein the first cap and the first end of the tube are coupled to each other so as to form an electrically conductive, gas-sealed connection between them, the connection including

a) interference-fit-based galling between a first segment of the first end of the aluminum tube and a corresponding first segment of the first cap, and

b) a high elongation polymer, having an elongation of 30% or greater, located between a second segment of the aluminum tube and a corresponding second segment of the first cap; and

wherein a thickness of the high elongation polymer, measured radially normal to a surface of the tube at the second segment of the connection, is less than 500 micrometers.

2. The muon drift tube of claim 1, wherein the connection comprises:

the segments being located so that the first segments are located between the second segments and an interior volume defined by an interior wall of the aluminum tube.

3. The muon drift tube of claim 1, wherein the connection comprises:

the segments being located so that the second segments are located between the first segments and an interior volume defined by an interior wall of the aluminum tube.

4. The muon drift tube of claim 1, wherein at least one of the first segments includes at least one protrusion.

5. The muon drift tube of claim 1, wherein at least one of the first segments is located on an interior wall of the aluminum tube.

6. The muon drift tube of claim 1, wherein at least one of the first segments is located on an exterior wall of the aluminum tube.

7. The muon drift tube of claim 1, wherein at least one of the second segments is located on an interior wall of the aluminum tube.

8. The muon drift tube of claim 1, wherein at least one of the second segments is located on an exterior wall of the aluminum tube.

9. The muon drift tube of claim 1, wherein the second segment of the aluminum tube includes a terminal end surface of the aluminum tube.

10. A muon drift tube for use in muon tomography comprising:

an aluminum tube having a first end, a second end, and a longitudinal axis;

an aluminum first cap coupled to the first end of the tube;

an aluminum second cap coupled to the second end of the tube;

a first electrode physically coupled to, but electrically isolated from, the first cap;

a second electrode physically coupled to, but electrically isolated from, the second cap;

a conductive wire within the tube extending, along the longitudinal axis, between the first electrode and the second electrode,

wherein a first segment of the first end of the aluminum tube and a first segment of the first cap are interference-fit together so as to form an electrically conductive path between them;

wherein a second segment of the first end of the aluminum tube and a corresponding second segment of the first cap are spaced apart from each other so as to form a gap between them of greater than 76.2 micrometers; and

a high elongation polymer, having an elongation of 30% or greater, bonded to at least one of the aluminum tube or first cap, and located within the gap, so that, the first segments and second segments will collectively form an electrically conductive, gas-sealed, connection between the first end cap and the aluminum tube.

11. The muon drift tube of claim 10, wherein the gap is less than 500 micrometers when measured in an radial direction.

12. The muon drift tube of claim 11, wherein the connection comprises:

the segments being located so that the first segments are located between the second segments and an interior volume defined by an interior wall of the aluminum tube.

13. The muon drift tube of claim 11, wherein the connection comprises:

the segments being located so that the second segments are located between the first segments and an interior volume defined by an interior wall of the aluminum tube.

14. The muon drift tube of claim 11, wherein at least one of the first segments includes at least one protrusion.

15. The muon drift tube of claim 11, wherein at least one of the first segments is located on an interior wall of the aluminum tube.

16. The muon drift tube of claim 11, wherein at least one of the first segments is located on an exterior wall of the aluminum tube.

17. The muon drift tube of claim 11, wherein at least one of the second segments is located on an interior wall of the aluminum tube.

18. The muon drift tube of claim 11, wherein at least one of the second segments is located on an exterior wall of the aluminum tube.

19. The muon drift tube of claim 11, wherein the second segment of the aluminum tube includes a terminal end surface of the aluminum tube.

20. A method of making a muon drift tube for use in muon tomography, the method comprising:

i) threading an anode wire through an aluminum tube having a first end, a second end, and a longitudinal axis, such that the wire extends beyond both the first end and second end of the aluminum tube;

ii) inserting a first end of the anode wire into a first electrode located within, but electrically isolated from, a first end cap;

iii) inserting a second end of the anode wire into a second electrode located within, but electrically isolated from, a second end cap;

iv) coupling a first part of the first end cap to the first end of the aluminum tube, and coupling a first part of the second end cap to the second end of the aluminum tube;

v) tensioning the anode wire such that the longitudinal axis of the aluminum tube and the anode wire are co-linear;

vi) coupling portions of the tensioned anode wire, associated with the first and second ends of the tensioned anode wire, to the first and second electrodes;

wherein, with respect to coupling the first end cap to the aluminum tube, a second segment of one of the first part of the first end cap, or a second segment of the first end of the aluminum tube, includes a high elongation polymer, having an elongation of 30% or greater, and a first segment of both the first part of the first end cap and a first segment of the second end of the aluminum tube are substantially free of the high elongation polymer;

wherein the coupling of the first part of the first end cap to the one end of the aluminum tube in “

iv)”

comprises interference fitting the first part of the first end cap and the first end of the aluminum tube together such that galling will occur between the respective first segments and

wherein the method further includes, forming a flexible seal between the respective second segments, such that the first and second segments collectively form an electrically conductive, gas-sealed, connection between the first end cap and the aluminum tube.

21. The method of claim 20 further comprising, prior to “

iv)”

;

roughening at least one of;

a) the second segment of the first end cap, or

b) the second segment of the first end of the aluminum tube.