Neutron detector with layered thermal-neutron scintillator and dual function light guide and thermalizing media

• US 20050224719A1
• Filed: 04/13/2004
• Published: 10/13/2005
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Leidos, Inc. (Leidos Holdings, Inc.)
• Original Assignee: Science Applications International Corporation
• Inventors: Baltgalvis, Janis, Polichar, Raulf M.
• Granted Patent: US 7,244,947 B2
• Time in Patent Office: Days
• US Class Current: 250/390.10
• CPC Class Codes: G01T 3/06 with scintillation detectors

Abstract

A broad spectrum neutron detector has a thermal neutron sensitive scintillator film interleaved with a hydrogenous thermalizing media. The neutron detector has negligible sensitivity to gamma rays and produces a strong and unambiguous signal for virtually all neutrons that interact with the hydrogenous volume. The interleaving of the layers of thermal neutron sensitive phosphors helps ensure that all parts of the thermalizing volume are highly sensitive.

Claims

1. A broad spectrum neutron detector comprising a thermal neutron sensitive scintillator film interleaved with a hydrogenous thermalizing media.

2. The neutron detector of claim 1 wherein the thermal neutron sensitive scintillator film comprises a material selected from the group consisting of ⁶Li—

ZnS, ¹⁰BN, and other alpha particle sensitive phosphors doped with ⁶Li or ¹⁰B.

3. The neutron detector of claim 1 wherein the hydrogenous thermalizing media comprises acrylic.

4. The neutron detector of claim 1 wherein the thermal neutron sensitive scintillator film has a layer thickness of about 0.1 mm to about 0.5 mm.

5. The neutron detector of claim 1 wherein the thermalizing media has a layer thickness of about 0.5 cm to about 1.5 cm.

6. The neutron detector of claim 1 further comprising a photo-sensor.

7. The neutron detector of claim 1 further comprising a wavelength shifter.

8. A portal detector comprising the neutron detector of claim 1.

9. A handheld instrument comprising the neutron detector of claim 1.

10. A neutron detector comprising a plurality of ⁶Li—

ZnS films optically coupled to a light guide-thermalizing media comprising a plurality of acrylic layers.

11. The neutron detector of claim 10 comprising at least four ⁶Li—

ZnS films and at least five acrylic layers.

12. The neutron detector of claim 10 wherein each of the ⁶Li—

ZnS films has a thickness of about 0.1 mm to about 0.5 mm.

13. The neutron detector of claim 10 wherein each of the high density polyethylene layers has a thickness of about 0.5 cm to about 1.5 cm.

14. The neutron detector of claim 10 further comprising a photo-sensor.

15. The neutron detector of claim 10 further comprising a wavelength shifter.

16. A portal detector comprising the neutron detector of claim 10.

17. A handheld instrument comprising the neutron detector of claim 10.

18. A neutron detector comprising:

a thermal neutron sensing scintillator comprising at least four ⁶Li—

ZnS films interleaved with and optically coupled to a light guide-thermalizing media comprising at least five acrylic layers;

a reflecting surface substantially enveloping said interleaved layers, wherein said reflecting surface comprises a tapered portion extending from an end of said interleaved layers for guiding light to a narrowed section; and

a photo-sensor located at the narrowed section of the tapered portion.

19. A portal detector comprising the neutron detector of claim 18.

20. A handheld instrument comprising the neutron detector of claim 18.