Lithium niobate explosion monitor
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsCharles H. Bundy, Robert A. Graham, Stephen F. Kuehn, Richard R. Precit, Michael S. Rogers
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Abstract
Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier.
Claims9
An explosive monitor including:
- means for providing an electrical output indicative of the detonation of an explosive material, said means comprising:
- a lithium niobate crystal wafer having spaced parallel faces cut substantially perpendicular to a unique polar axis "z";
- and
- first means for detecting a piezoelectric current output of said crystal indicative of the detonation of an explosive material;
- and
- checking means for nondestructively checking the responsiveness of said crystal prior to detonation of the explosive material, said checking means comprising:
- second means for controllably heating said crystal;
- and
- third means for detecting a pyroelectric charge output of said crystal responsive to the heating of said crystal by said second means.
A method for monitoring the detonation of an explosion comprising:
- positioning adjacent an explosive a negative face of a lithium niobate crystal wafer having spaced parallel faces cut substantially perpendicular to a unique polar axis "z";
- impinging a thermal pulse on said crystal;
- measuring the electrical charge generated by crystal as a result of said thermal pulse to check the responsiveness of said crystal;
- and
- measuring the piezoelectric current generated by said crystal as a result of the impact of the explosion on said crystal face.
Dependencies are inferred from the claim text.