1. Field of the Invention
The invention relates to a sensor apparatus and a set of methods used to detect biological agents and chemical compounds using optical methods. The sensing apparatus consists of several electrical and optical elements including a tunable laser, a photodetector, a digital controller and a wireless transmitter. The methods consist of several processes needed to control the sensor including laser wavelength tuning, photodetector control, data conditioning and transmission protocol software.
2. Description of the Related Art
A typical approach used to detect agents or chemicals uses Laser Induced Breakdown Spectroscopy (LIBS). High power laser light is applied to the sample, which is then vaporized into plasma. As the sample is vaporized a broadband spectrum of light is emitted due to multiple electronic transitions. The light is then sent to an optical spectrum analyzer that in turn determines the profile of wavelength versus intensity for the sample analyzed. The spectrum data is then processed by means of digital signal processing (DSP) in a computer in order to filter out noise in the spectrum. Finally, the resultant filtered spectrum is compared with a database of signatures for known biological and chemical agents. Some disadvantages of the LIBS approach are:
The invention consists of an unknown agent detection methods and an apparatus. The sensing apparatus consists of a sensor and PDA-phone. The method used in this invention is referred to as Laser Induced Spectroscopy. However, in this invention, tunable lasers are used in order to improve results. The sensor contains an array of tunable lasers. A digital controller contained in the sensor controls each laser. The digital controller ensures that the laser emits light in a narrow band of light frequencies. Typical region for analyzing chemical materials and biological agents is in the 300 nanometers to 900 nanometers of light wavelength. Each laser is tuned to a narrow wavelength of light; the amount of laser power is also controlled to a given level. Wavelength and power are set in an appropriate manner so as to obtain a strong emitted spectrum from the unknown agent. Wavelength of the light source is continuously changed from one region of the spectrum to another with an appropriate amount of power in order to detect a strong and reliable spectrum. Each time we change the wavelength and power of the appropriate laser, the detected spectrum is digitized. After the information is digitized, it is sent to a portable Personal Digital Assistant and telephone unit (PDA-phone) for storage. Once an entire sweep of wavelengths and power has been carried out with a corresponding emitted spectrum digitized and stored, the PDA-phone will transmit through wireless means the data to a remote server. The remote server can contain Digital Signal Processing programs used to filter the information. The server can also contain an analysis tool and databases to determine what is the chemical or agent. The server can also connect through the Internet or other means to databases in research laboratories. Once the agent is identified, the system can transmit to the PDA-phone information related to the identity of the agent or instructions on how to proceed if the agent poses a danger to the operator. Arrays of the sensors described ion this invention can be placed in the filed. Data from the array can be collected through wireless means by using a hub. An advantage of the invention is that the detected spectrum (305) will exhibit a high signal to noise ratio. This will increase the reliability of the detection. Another advantage of the invention is that the detection process does not destroy the sample.
Yet another advantage of the invention is that the sensor is portable and exhibits increased accuracy due to the use of databases in remote server (403)
Details of the invention, and of the preferred embodiment thereof will be further understood upon reference to the drawings:
Figure (400) shows the entire apparatus and methods for agent identification. Once the emitted spectrum (305) is sensed by the probe (301), information is transferred through the wireless link to a compatible PDA-phone (401). The PDA-phone (401) transfers the sensor information through wireless transmission (402) to a remote server (403). The remote server (403) contains high performance computers and extensive databases to conduct an analysis of the spectrum for the unknown agent (103). The remote server (403) can be connected by alternative means to extensive databases resident in research centers. The remote server performs unknown agent identification using information form the databases. Once the identity of the agent has been established, the server will transmit to the PDA-phone appropriate instructions regarding actions to be taken by the operator or precautions if the agent poses a danger.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US04/05627 | 2/25/2004 | WO | 5/16/2006 |
Number | Date | Country | |
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60450223 | Feb 2003 | US |