Diamond radiation detector

• US 7,368,723 B2
• Filed: 09/04/2003
• Issued: 05/06/2008
• Est. Priority Date: 09/06/2002
• Status: Expired due to Term

• Current Assignee: Element Six Technologies US Corporation (Anglo American PLC)
• Original Assignee: Element Six (Holdings) Ltd. (Anglo American PLC)
• Inventors: Scarsbrook, Geoffrey Alan, Twitchen, Daniel James, Whitehead, Andrew John
• Primary Examiner(s): Porta; David
• Assistant Examiner(s): Baker; David S
• Application Number:
  US10/526,403
• Publication Number:
  US 20060071169A1
• Time in Patent Office: 1,706 Days
• Field of Search: 250/370, 250/370.01
• US Class Current: 250/370.01
• CPC Class Codes: G01T 1/26 with resistance detectors photoresistors H01L31/00

Abstract

A method of detecting radiation that includes providing a layer of high purity single crystal CVD diamond, applying an electric field of no greater than 0.5 V/μm to the layer, exposing the layer to the radiation thereby generating a signal, and detecting the signal.

Claims

1. A method of detecting radiation comprising:

providing a layer of high purity single crystal CVD diamond having at least one of,

(i) in an off state, a resistivity R₁ greater than 1×

10¹² Ω

cm measured at an applied field of 50 V/μ

m and 300 K,

(ii) a μ

τ

product greater than 1.5×

10<sup>−

6</sup> cm²/V, measured at an applied field of 10 V/μ

m and 300 K,

(iii) an electron mobility (μ

_e) measured at 300 K greater than 2400 cm²V<sup>−

1</sup>s<sup>−

1</sup>,

(iv) a hole mobility (μ

_h) measured at 300 K greater than 2100 cm²V<sup>−

1</sup>s<sup>−

1</sup>, and

(v) a high charge collection distance greater than 150 μ

m, measured at an applied field of 1 V/μ

m and 300 K;

applying an electric field of no greater than 0.5 V/μ

m to the layer;

exposing the layer to the radiation thereby generating a signal; and

detecting the signal.

2. A method according to claim 1 wherein the electric field applied to the diamond layer is less than 0.3 V/μ

m.

3. A method according to claim 1 wherein the electric field applied to the diamond layer is less than 0.2 V/μ

m.

4. A method according to claim 1 wherein the electric field applied to the diamond layer is less than 0.15 V/μ

m.

5. A method according to claim 1 wherein a thickness of the layer does not exceed 1 mm.

6. A method according to claim 1 wherein a thickness of the layer is less than 500 μ

m.

7. A method according to claim 1 wherein a thickness of the layer is less than 250 μ

m.

8. A method according to claim 1 wherein a bias voltage less than 300 V is applied to the layer.

9. A method according to claim 1 wherein a bias voltage less than 200 V is applied to the layer.

10. A method according to claim 1 wherein a bias voltage less than 100 V is applied to the layer.

11. A method according to claim 1 wherein a bias voltage less than 75 V is applied to the layer.

12. A method according to claim 1 wherein the CVD diamond layer reaches at least 80% of saturated charge collection efficiency at the applied electric field.

13. A method according to claim 1 wherein the CVD diamond layer reaches at least 90% of saturated charge collection efficiency at the applied electric field.

14. A method according to claim 1 wherein the CVD diamond layer reaches at least 95% of saturated charge collection efficiency at the applied electric field.

15. A method according to claim 1 wherein the CVD diamond layer is capable of generating at least 7000 electrons per detection event for minimum ionising particles when operated at the applied electric field.

16. A method according to claim 1 wherein the CVD diamond layer is capable of generating at least 9000 electrons per detection event for minimum ionising particles when operated at the applied electric field.

17. A method according to claim 1 wherein the CVD diamond layer is capable of generating at least 12000 electrons per detection event for minimum ionising particles when operated at the applied electric field.

18. A method according to claim 1 wherein the CVD diamond layer is capable of generating at least 15000 electrons per detection event for minimum ionising particles when operated at the applied electric field.

19. A method according to claim 1 wherein the radiation is alpha particles and the CVD diamond is such that it generates a peak width (FWHM) in energy, expressed as δ

E/E, less than 20%.

20. A method according to claim 1 wherein the radiation is selected from beta particles, alpha particles, protons, other high energy nuclear particles, and high energy electromagnetic radiation.

21. A method according to claim 1 wherein the radiation is neutrons.

22. A detector including a stand-alone, remote or hand-held device comprising:

a layer of high purity single crystal CVD diamond configured to operate at a bias voltage of less than 100V and having one or more of,

(i) in an off state, a resistivity R₁ greater than 1×

10¹² Ω

cm measured at an applied field of 50 V/μ

m and 300 K,

(ii) a μ

τ

product greater than 1.5×

10<sup>−

6</sup> cm²/V, measured at an applied field of 10 V/μ

m and 300 K.

(iii) an electron mobility (μ

_e) measured at 300 K greater than 2400 cm²V<sup>−

1</sup>s<sup>−

1</sup>,

(iv) a hole mobility (μ

_h) measured at 300 K greater than 2100 cm²V<sup>−

1</sup>s<sup>−

1</sup>, and

(v) a high charge collection distance greater than 150 μ

m, measured at an applied field of 1 V/μ

m and 300 K;

23. A detector according to claim 22 wherein the layer of high purity single crystal CVD diamond has a thickness of less than 1 mm.