Self powered neutron detector
View Patent ↗A self-powered neutron detector having an emitter with a slightly negative bias voltage that assures that an increase in the electrons that enter the insulator are counted and decreases or eliminates the gamma induced prompt signal. Variations in the size of the bias is used as a diagnostic tool to estimate the gamma induced prompt signal.
1. A self-powered neutron detector comprising:
a neutron sensitive emitter element;
an annular insulator substantially coaxially disposed around the emitter element;
an outer electrically conductive sheath disposed around the annular insulator; and
a negative bias voltage applied to the neutron sensitive emitter.
2. The self-powered neutron detector of claim 1 wherein the negative bias voltage is approximately between 1 and 30 volts.
3. The self-powered neutron detector of claim 2 wherein the negative bias voltage is approximately between 1 and 2 volts.
4. The self-powered detector of claim 1 including a coating of a material that enhances the photoemissivity of the emitter, around at least a portion of the outside of the emitter.
5. The self-powered detector of claim 4 wherein the coating comprises selenium.
6. The self-powered detector of claim 1 including means for varying the negative bias voltage.
7. A nuclear fuel assembly having an instrument thimble housing a self-powered neutron detector comprising:
a neutron sensitive emitter element;
an annular insulator substantially coaxially disposed around the emitter element;
an outer electrically conductive sheath disposed around the annular insulator; and
a negative bias voltage applied across the neutron sensitive emitter.
8. The nuclear fuel assembly of claim 7 wherein the negative bias voltage is approximately between 1 and 30 volts.
9. The nuclear fuel assembly of claim 8 wherein the negative bias voltage is approximately between 1 and 2 volts.
10. The nuclear fuel assembly of claim 7 including a coating of a material that enhances the photoemissivity of the emitter, around at least a portion of the outside of the emitter.
11. The nuclear fuel assembly of claim 10 wherein the coating comprises selenium.
12. The self-powered detector of claim 7 including means for varying the negative bias voltage.
13. A nuclear reactor system including a fuel assembly having an instrument thimble housing a self-powered detector comprising:
a neutron sensitive emitter element;
an annular insulator substantially coaxially disposed around the emitter element;
an outer electrically conductive sheath disposed around the annular insulator; and
a negative bias voltage applied across the neutron sensitive emitter.
14. The nuclear reactor system of claim 13 wherein the negative bias voltage is approximately between 1 and 30 volts.
15. The nuclear reactor system of claim 14 wherein the negative bias voltage is approximately between 1 and 2 volts.
16. The nuclear reactor system of claim 13 including a coating of a material that enhances the photoemissivity of the emitter, around at least a portion of the outside of the emitter.
17. The nuclear reactor system of claim 16 wherein the coating comprises selenium.
18. The self-powered detector of claim 13 including means for varying the negative bias voltage.