Compact handheld non-laser detector for greenhouse gasses

Abstract

Techniques are disclosed relating to gas leak detection. The techniques can be deployed, for example, in compact, handheld portable devices usable for detecting leaks in space-confined applications. The devices generally include a non-laser light source and thermal imaging camera that allow for detection of a target gas (or gasses) that absorbs at least some of the light source's wavelengths of operation. The light source can be implemented, for example, with an incoherent infrared (IR) light source, such as a resonance lamp configured with a gas cell containing a volume of a gas that, when excited by electric discharge, emits a wavelength that is absorbed by the target gas.

1 . A gas leak imaging system, comprising:
 a non-laser incoherent light source for providing a light beam having at least one wavelength that is absorbable by a target gas; and   a thermal imaging camera having a field of view and for imaging absorption of the at least one wavelength by the target gas;   wherein the system is contained in a handheld housing.   
     
     
         2 . The system of  claim 1  wherein the target gas is sulfur hexafluoride (SF 6 ). 
     
     
         3 . The system of  claim 1  wherein the light source is configured for expanding the light beam toward the field of view. 
     
     
         4 . The system of  claim 1  wherein the camera is a longwave infrared camera. 
     
     
         5 . The system of  claim 1  wherein the light source is a resonance lamp, comprising:
 a cell that contains a volume of gas;   an excitation coil wrapped with a number of turns around the cell; and   an excitation source operatively coupled to the coil;   wherein in response to the excitation source energizing the coil, radiation is emitted from the cell that is in resonance with absorption lines of the target gas.   
     
     
         6 . The system of  claim 5  wherein the resonance lamp is configured with a transmitting window for expanding the light beam toward the field of view, such that radiation emitted from the cell is transmitted by the transmitting window toward the field of view. 
     
     
         7 . The system of  claim 6  wherein the transmitting window is a germanium or zinc selenide diverging lens. 
     
     
         8 . The system of  claim 6  wherein the resonance lamp further includes a rear mirror for reflecting radiation within the cell toward the transmitting window. 
     
     
         9 . The system of  claim 5  wherein the volume of the gas contained in the cell is the same as the target gas. 
     
     
         10 . The system of  claim 5  wherein the excitation source is one of an RF oscillator or a pulse width modulation source or an RF waveguide excitation source. 
     
     
         11 . The system of  claim 1  wherein the non-laser incoherent light source is a modified laser. 
     
     
         12 . The system of  claim 11  wherein the modified laser has been modified by replacing its output mirror with the transmitting window, and replacing its gaseous lasing medium with a gas capable of emitting radiation that is in resonance with absorption lines of the target gas. 
     
     
         13 . The system of  claim 11  wherein the target gas is sulfur hexafluoride (SF 6 ). 
     
     
         14 . A gas leak imaging system, comprising:
 a resonance lamp for providing a light beam having at least one wavelength that is absorbable by a target gas, the lamp is configured with a transmitting window for expanding the light beam toward the field of view; and   a thermal imaging camera having a field of view and for imaging absorption of the at least one wavelength by the target gas;   wherein the system is contained in a handheld housing.   
     
     
         15 . The system of  claim 14  wherein the target gas is sulfur hexafluoride (SF 6 ). 
     
     
         16 . The system of  claim 14  wherein the camera is a longwave infrared camera. 
     
     
         17 . The system of  claim 14  wherein the resonance lamp further comprises:
 a cell that contains a volume of a gas;   an excitation coil wrapped with a number of turns around the cell;   an excitation source operatively coupled to the coil; and   a rear mirror for reflecting radiation within the cell toward the transmitting window;   wherein in response to the excitation source energizing the coil, radiation is emitted from the cell that is in resonance with absorption lines of the target gas.   
     
     
         18 . The system of  claim 14  wherein the modified laser has been modified by replacing its output mirror with the transmitting window, and replacing its gaseous lasing medium with a gas capable of emitting radiation that is in resonance with absorption lines of the target gas. 
     
     
         19 . A gas leak imaging method, comprising:
 providing a light beam from a non-laser incoherent light source to a field of view, the light beam having at least one wavelength that is absorbable by a target gas;   expanding the light beam toward the field of view; and   imaging absorption of the at least one wavelength by the target gas;   wherein the light source is contained in a handheld device that is capable of carrying out the method.   
     
     
         20 . The method of  claim 19  wherein the non-laser incoherent light source is a resonance lamp comprising:
 a cell that contains a volume of a gas;   an excitation coil wrapped with a number of turns around the cell;   an excitation source operatively coupled to the coil; and   a rear mirror for reflecting radiation within the cell toward the transmitting window;   wherein in response to the excitation source energizing the coil, radiation is emitted from the cell that is in resonance with the target gas's absorption lines.