DE2947459A1 - Detecting poisonous substances covering ground - using passing vehicle causing luminescence by e.g. laser beam, for analysis via opto-electronic system - Google Patents

Abstract

Poisonous substances assumed to be covering the ground, track, roadway etc. are detected in-situ so that the contaminated area can be guarded off as quickly as possible. Time is not lost on the identification of separate substances. Rather the presence of certain classes of substances is detected. A luminescent beam is generated by a vehicle and received and analysed through an opto-electronic system. A luminescent combination is formed through reaction between the poisonous covering and a corresp. reagent. The reaction takes place at the front of the vehicle while the luminescent radiation is received at the back of the vehicle. The speed of the vehicle is adjusted to the luminescence time.

Description

Procedure and arrangement for in-situ follow-up

knowledge of floor coverings of suspected toxic substances The invention relates to a method for the in-situ detection of suspected toxic floor coverings Substances that generate luminescence radiation from a moving vehicle and is received and analyzed by an opto-electronic system, as well as an arrangement for the implementation of this procedure.

To determine the presence of toxic surface coatings should the measurements from a counter Exposure to poison Can be carried out on the occupant protected vehicle. So that a flagged one Area can be demarcated and marked as quickly as possible, evidence must be provided during the journey. It is less clamped on the identification of individual substances, ; or on the detection of the presence of certain classes of hazard.

For the detection of toxic floor coverings, a Vehicle taken out while driving with suitable devices soil samples and then brought to physical or chemical analysis. The sampling can be done in a number of ways, such as scraping, dabbing, or vacuuming (if necessary after previous surface heating) of the floor. All these Methods have the common and major disadvantage, dan the contact of the contaminated Material with the sampling and detection devices are not prevented can. [In addition, continuous measurements are only possible with certain surface properties are possible because soil samples are taken with mechanical devices.

In addition, individual embodiments have these methods still specific disadvantages, e.g. weather dependency, etc.

The invention as characterized in claims 1-9 is, solves the problem of specifying a method and an arrangement with which or with the toxic floor coverings, especially chemical warfare agents, contactless from can be detected from a moving vehicle.

According to the method of the invention, the toxic floor covering is with a liquid suitable for the formation of a luminescent compound moisturizes. The resulting compound can either through the reaction energy (chemiluminescence) or by a light source, e.g. laser, (fluorescence) to radiation be stimulated.

The method according to the invention is particularly suitable for the detection of deposits of special sedentary chemical warfare agents from the group of phosphoric acid esters. These substances have the general formula in which R1 and R2 are an alkyl, aryl, alkoxy or alkylamino group and X is a halogen atom or a CN group.

Alkyl or alkoxy groups are preferably of low molecular weight Groups with 1 to 8 carbon atoms. These include, for example, isopropyl methylfluorophosphonate (Sarin), methylfluorophosphonic acid trimethylpropyl ester (Soman), dimethylphosphoramidocyanoic acid ethyl ester (Tabun) and diisopropyl fluorophosphonate (DFP). But also others, from the above formula Warfare agents not covered, e.g. tetraethyl pyrophosphonate (TEPP) and hexaethyl tetraphosphonate (HETP) can be detected with the appropriate reagents. All of these connections show no evaluable fluorescence themselves.

To generate a luminescent compound are known per se Reactions are used (e.g. "Analytical Chemistry", 29 (1957), pp. 276-278). To the Detection of nerve gases such as sarin, soman and tabun is e.g. a reagent solution from indole and sodium perborate in acetone and water sprayed onto the toxic floor covering. As a result of the formation of an indoxyl or indigo white compound, appears on irradiation strong green fluorescence with a UV light source.

The invention enables certain chemical floor coverings to be made contactless to be demonstrated while driving from a hermetically sealed vehicle. The arrangement according to the invention is also by day and night and by different Soil conditions and weather conditions can be used, provided these do not disappear effect of the covering from the surface, e.g. insuring. Furthermore, it does not matter whether the covering is in liquid form, e.g. droplets, or solid dried ones Form.

In the following the invention is based on only one embodiment Illustrative drawing explained in more detail.

The arrangement according to the invention is hermetically sealed to the outside Vehicle installed. It consists of two units, namely device A for dispensing the reagent liquid and device B for optical and electronic analysis the luminescent radiation.

The device A consists essentially of a storage container 1 for the reagent liquid and a spray device 2, which are connected to each other via a line 3 are connected. The spray device 2 can be on the vehicle floor in this way be appropriate that they when cornering depending on the curve radius is displaceable transversely to the longitudinal axis of the vehicle. Furthermore, the spray width be changeable. These measures ensure that with as little as possible Reagent consumption of the moistened floor strip always below the receiving system runs.

In the illustrated embodiment, the device B consists of a light source 4, e.g. a laser, and a device for receiving and analyzing the luminescent radiation. The receiving and analysis device contains an electronic Evaluation unit 5 with display, an optical detector 6 (photomultiplier), a monochromator 7 and an optical system 8.

The two devices A and B are at a certain distance a mounted in the vehicle. The toxic floor covering of occupancy density Q is with the reagent liquid moistened by means of spray devices 1 and 2 over a width b. This initiates the reaction, in the course of which a fluorescent compound is created arises. If the occupancy density is greater than a minimum value of 5 minutes, SG is formed after a certain time T1 so much fluorescent compound that the sensitivity the analysis device is sufficient to provide evidence. The vehicle speed v must be set so that the overrun time T2 = a / v is greater than T1.

The device B contains a pulsed nitrogen laser as a light source 4, which emits radiation with a wavelength of 337 nm.

The pulse repetition frequency l / r is typically 100 Hz, the pulse duration at 200 ps. At time t a laser pulse is sent out and over an optical system with deflection mirror 9 through a window 10 in the vehicle floor directed a part of the moistened strip with a spot diameter d. By the laser radiation becomes the connection formed for the emission of a fluorescence radiation pulse excited in the wavelength range around 500 nm.

The fluorescence radiation is received by an optical system 8, spectrally broken down by the frequency-selective element 7, registered by photodetectors 6 and processed by the electronic evaluation unit 5. At times t + and (n = 1, 2, 3, ...), further laser pulses are emitted and fluorescence pulses are registered. Since the vehicle moves with the speed v, a different area with the diameter d is irradiated by each laser pulse. In this case, d is expediently chosen so that successively irradiated areas touch or overlap. If, for example, d = 2 vt is set, then it becomes a strip of width continuously covered.

Preferably the direction is the optical axis of the device B deflectable transversely to the longitudinal axis of the vehicle, so that the moistened floor strip can be scanned point by point over a broader area.

For the analysis, the fluorescence radiation in the polychromator 7 in spectral intervals (channels) broken down. The distribution of the intensity over the spectral Channels is characteristic of the fluorescent substance, e.g. indoxyl. By Determination of the intensity distribution can determine the presence of the connection formed be detected. The number of spectral channels determines the selectivity the detection and the sensitivity to background influences. To the results the spectral components spatially separated by the polychromator 7 are from the detector 6 converted into associated electrical signals and stored in the electronic system 5 processed. Electrical quantities derived from the signals are included stored values compared to those for the spectrum of the compound formed character- are teristic. At a given level of correspondence A message appears on a display device that the expected connection exists is.

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Claims (9)

Claims 1. Method for in-situ detection of floor coverings suspected toxic substances in which a Luminescence radiation generated and received by an optoelectronic system and is analyzed, characterized in that by reaction between the toxin coating and a luminescent compound is formed with a corresponding reagent, wherein the reagent is applied to the front part of the vehicle, and the luminescent radiation received at the rear of the vehicle and analyzed in known wheat is the quotient of the distance between the exit point of the reagent and the @@@@ @@@@ @@@@ of the receiving system and the speed of Vehicle is set so that it is approximately equal to that for the emergence of the luminescent Connection is required time. 2. The method according to claim 1, characterized in that when cornering the position and the width of the soil strip moistened with the reagent and the minimum curve radius can be adjusted so that the moistened strip always runs below the receiving system. 3. The method according to claim 1 and 2, characterized in that the Luminescence radiation through the reaction energy or through one carried by the vehicle Light source, preferably laser, is excited. 4. Application of the method according to any one of claims 1 to 3, for Detection of chemical warfare agents from the group of phosphoric acid esters. 5. Arrangement for the in-situ detection of floor coverings of toxic substances from a moving vehicle according to the principle of luminescence excitation and analysis, characterized in that a device A (1,2,3) on the front part of the vehicle is attached to the soil surface for applying a reagent liquid, and that at the rear of the vehicle a device B (5,6,7,8) for receiving and provided for optical and electronic analysis of the luminescence is, where the distance between the two devices is equal to the product of the speed of the vehicle and the required for the creation of the luminescent connection Time is. 6. Arrangement according to claim 5, characterized in that the device A has a spray device (2), the width of which can be changed. 7. Arrangement according to claim 5 and 6, characterized in that the Spray device (2) is displaceable transversely to the longitudinal axis of the vehicle. 8. Arrangement according to one of claims 5 to 7, characterized in that that the device B has a light source (4), preferably a laser, for exciting Fluorescence radiation and an optical system (9) for guiding the excitation radiation contains. 9 arrangement according to one of claims 5 to 8, characterized in that that the direction of the optical axis of the device B is transverse to the longitudinal axis of the vehicle is deflectable.