SYSTEMS AND METHODS FOR TRACE CHEMICAL DETECTION USING DUAL PHOTOIONIZATION SOURCES
A dual source ionizer is provided. The dual source ionizer includes a first photoionization source configured to emit low flux ultraviolet (UV) light to generate primarily NO 3 − ions, and a second photoionization source configured to emit high flux UV light to generate primarily ions other than NO 3 − ions.
1 . A dual source ionizer comprising:
a first photoionization source configured to emit low flux ultraviolet (UV) light to generate primarily NO 3 − ions; and
a second photoionization source configured to emit high flux UV light to generate primarily ions other than NO 3 − ions.
2 . The dual source ionizer of claim 1 , further comprising a controller communicatively coupled to said first and second photoionization sources and configured to selectively disable said second photoionization source for a period of time while said first photoionization source is enabled.
3 . The dual source ionizer of claim 1 , wherein at least one of said first photoionization source and said second photoionization source comprises a krypton discharge lamp.
4 . The dual source ionizer of claim 1 , wherein the first and second photoionization sources are the same photoionization source.
5 . The dual source ionizer of claim 1 , wherein the first and second photoionization sources are separate photoionization sources.
6 . The dual source ionizer of claim 1 , wherein the first photoionization source is configured to emit UV light having a flux less than approximately 3.75×10 12 photons per second.
7 . The dual source ionizer of claim 1 , wherein the first photoionization source is configured to emit UV light having a flux in a range between approximately 3.75×10 12 photons per second and 1.0×10 14 photons per second.
8 . The dual source ionizer of claim 1 , wherein the second photoionization source is configured to emit UV light having a flux on the order of 10 15 photons per second.
9 . A method of ionizing a gas, the method comprising:
ionizing the gas using a first photoionization source that emits low flux ultraviolet (UV); and
ionizing the gas using a second photoionization source that emits high flux UV.
10 . The method of claim 9 , further comprising selectively disabling the second photoionization source for a period of time while the first photoionization source is enabled.
11 . The method of claim 9 , wherein ionizing the gas using a first photoionization source comprises ionizing the gas using a krypton discharge lamp.
12 . The method of claim 9 , wherein ionizing the gas using a second photoionization source comprises ionizing the gas using a krypton discharge lamp.
13 . The method of claim 9 , wherein ionizing the gas using a first photoionization source and wherein ionizing the gas using a second photoionization source comprise ionizing the gas using the same photoionization source.
14 . The method of claim 9 , wherein ionizing the gas using a first photoionization source and wherein ionizing the gas using a second photoionization source comprise ionizing the gas using separate photoionization sources.
15 . The method of claim 9 , wherein ionizing the gas using a first photoionization source comprises ionizing the gas using a first photoionization source that emits UV light having a flux less than approximately 3.75×10 12 photons per second.
16 . The method of claim 9 , wherein ionizing the gas using a first photoionization source comprises ionizing the gas using a first photoionization source that emits UV light having a flux in a range between approximately 3.75×10 12 photons per second and 1.0×10 14 photons per second.
17 . The method of claim 9 , wherein ionizing the gas using a second photoionization source comprises ionizing the gas using a second photoionization source that emits UV light having a flux on the order of 10 15 photons per second.
18 . A trace detection system comprising:
a chamber configured to contain a gas composed of at least a vapor of a chemical substance sample;
a first photoionization source configured to emit low flux ultraviolet (UV) light to generate primarily NO 3 − ions from the gas; and
a second photoionization source configured to emit high flux UV light to generate primarily ions other than NO 3 − ions from the gas.
19 . The trace detection system of claim 18 , further comprising a spectrometer configured to screen ions generated from the gas for both nitrate-based explosives and for non-nitrate-based explosives.
20 . The trace detection system of claim 18 , further comprising a controller communicatively coupled to said first and second photoionization sources and configured to selectively disable said second photoionization source for a period of time while said first photoionization source is enabled.