Diamond .alpha. particle detector

• US 5,212,385 A
• Filed: 08/19/1991
• Issued: 05/18/1993
• Est. Priority Date: 08/17/1990
• Status: Expired due to Fees

• Current Assignee: Barbara L. Jones
• Original Assignee: Barbara L. Jones
• Inventors: Jones, Barbara L.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US07/747,267
• Time in Patent Office: 638 Days
• Field of Search: 250/370.01, 250/370.07
• US Class Current: 250/370.01
• CPC Class Codes: G01T 1/26 with resistance detectors photoresistors H01L31/00

Abstract

A radiation detector element which is optimized for the detection of α particles comprises a layer of diamond or diamond-like carbon with first and second electrical contacts applied to the surface of the layer. The layer is formed on a silicon substrate, together with an electronic circuit. Each of the contacts defines a rectifying junction with the layer, thus defining a back-to-back diodic structure, having junction characteristics which are responsive to the intensity of radiation incident on the detector element. The electronic circuit is powered by a battery or a solar cell, and activates an LCD indicator if the intensity of the incident radiation exceeds a predetermined level. The radiation detector element and the electronic circuit are housed on a card which is sized similarly to a conventional identification card.

Claims

1. A radiation detector element comprising a layer of diamond or diamond-like carbon with first and second electrical contacts applied thereto, with at least one of the contacts defining a rectifying junction with the diamond or diamond-like carbon layer which is responsive to the intensity of radiation incident on the detector element.

2. A radiation detector element according to claim 1 wherein both first and second electrical contacts define rectifying junctions with the diamond or diamond-like carbon layer in a back-to-back diodic structure.

3. A radiation detector element according to claim 1 wherein the thickness of the diamond or diamond-like carbon layer is optimised for the detection of α

particles.

4. A radiation detector element according to claim 1 wherein the diamond or diamond-like carbon layer is a chemical vapour deposition layer.

5. A radiation detector element according to claim 4 including a supporting substrate on which the diamond or diamond-like carbon layer is deposited.

6. A radiation detector element according to claim 5 wherein the supporting substrate comprises silicon.

7. A radiation detector element according to claim 6 wherein the supporting substrate is a silicon chip or wafer on which an electronic circuit is formed.

8. A radiation detector comprising a radiation detector element according to claim 1, and an electronic circuit means connected electrically to the radiation detector element for applying a bias voltage to the electrical contacts thereof, and for measuring the response of the radiation detector element to incident radiation.

9. A radiation detector according to claim 8 wherein the electronic circuit means reverse biases at least one of the rectifying junctions, and detects variations in the junction characteristics due to radiation incident on the detector element.

10. A radiation detector according to claim 9 wherein the electronic circuit means monitors the reverse breakdown voltage of the junction or junctions.

11. A radiation detector according to claim 8 wherein the electronic circuit means provides an analog output voltage which varies in accordance with the intensity of radiation incident on the detector element.

12. A radiation detector according to claim 8 including a power supply means for powering the electronic circuit, and an indicator means responsive to an output signal of the circuit for providing an indication to a user of the detector when the intensity of radiation incident on the detector element reaches a predetermined level.

13. A radiation detector according to claim 12 wherein the power supply means is a battery.

14. A radiation detector according to claim 12 wherein the power supply means is a solar cell.

15. A radiation detector according to claim 12 including a card-like substrate on which the radiation detector element is formed.

16. A radiation detector according to claim 1 including a single silicon wafer on which an electronic circuit, electrically coupled to the radiation detector element, and the radiation detector element are fabricated.