AN ELECTRON CAPTURE DETECTOR OPERATING WITH A SCINTILLATION CRYSTAL

Abstract

The invention relates to a detector (100) which comprises at least one data output line (1) in connection with an electronic mechanism (200), at least one column input (2), which is connected to the detector outlet column of a gas chromatography device and to which the sample from which the chromatography data is to be obtained is sent, at least one gas inlet (3) so that preferably nitrogen gas can enter, at least one gas outlet (4) for gas to exit from the detector (100), at least one gas mixing area (5) for mixing the gas sent from the column inlet (2) and preferably N2 gas sent from the gas inlet (3), at least one radioactive measurement chamber (13), at least one gas inlet line (6) for transferring the gas to said radioactive measurement chamber (13), at least one radioactive or non-radioactive light emitting source (9), preferably at least one shielding material (10) that prevents gases from exiting the shielding area, at least one gas outlet line (11) for the gas to exit from said radioactive measurement chamber (13), at least one outlet chamber (14) preferably to allow the gas to exit, at least one scintillator crystal (7) over which the electrical signal is formed with the current applied by the first power source (17) and which interacts with the gases which are mixed in the said measurement chamber (13), wherein the scintillator crystal allows the formation of an optical signal by emitting photons which have specific emission wavelengths as a result of the gases with which it interacts and of the current applied to the photodetector (19) unit, or without the application of current, has an uncoated outer surface or is coated with a conductive coating (8), the outer surface of which has a predetermined thickness in addition to the optical signal for obtaining the electrical signal, preventing the corrosion which will occur thereon and separating the signal of low energy electrons from the optical signal, and at least one fixing apparatus (12) that carries the data of the light coming from the fiber optic cable inside said scintillator crystal (7) or with said photodetector (19) placed on the surface thereof, fixes the scintillator crystal (7) and transfers the electrical data from the scintillator crystal (7) to the data output line (1).

Claims

1. A detector (100), characterized in that it comprises at least one data output line (1) in connection with an electronic mechanism (200), at least one column input (2), which is connected to the detector outlet column of a gas chromatography device and to which the sample from which the chromatography data is to be obtained is sent, at least one gas inlet (3) so that preferably nitrogen gas can enter, at least one gas outlet (4) for gas to exit from the detector (100), at least one gas mixing area (5) for mixing the gas sent from the column inlet (2) and preferably N.sub.2 gas sent from the gas inlet (3), at least one radioactive measurement chamber (13), at least one gas inlet line (6) for transferring the gas to said radioactive measurement chamber (13), at least one radioactive or non-radioactive light emitting source (9), at least one shielding material (10) that preferably prevents gases from exiting the shielding area, at least one gas outlet line (11) for the gas to exit from said radioactive measurement chamber (13), at least one outlet chamber (14) preferably to allow the gas to exit; and in that it preferably comprises at least one scintillator crystal (7) over which the electrical signal is formed with the current applied by the first power source (17) and which interacts with the gases which are mixed in the said measurement chamber (13), wherein the scintillator crystal allows the formation of an optical signal by emitting photons which have specific emission wavelengths as a result of the gases with which it interacts and of the current applied to the photodetector (19) unit, or without the application of current, has an uncoated outer surface, or is coated with a conductive coating (8), the outer surface of which has a predetermined thickness for obtaining the electrical signal in addition to the optical signal, preventing the corrosion which will occur thereon and separating the signal of low energy electrons from the optical signal, and at least one fixing apparatus (12) that carries the data of the light coming from the fiber optic cable inside said scintillator crystal (7) or with said photodetector (19) placed on the surface thereof, fixes the scintillator crystal (7) and transfers the electrical data from the scintillator crystal (7) to the data output line (1).

2. A detector (100) according to the claim 1, characterized in that it comprises YAP (Ce) or YAG (Ce) or LYSO or CdWO4 and Nal (TI) or CaF.sub.2 scintillator crystals (7).

3. A detector (100) according to the claim 2, characterized in that it comprises a conductive coating (8) which is a metal with a high conductivity such as gold, platinum, silver.

4. A detector (100) according to the claim 3, characterized in that it comprises a conductive coating (8) which has a thickness of 100 nm.

Description

DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a view of a cross-section of the detector of the invention.

[0012] FIG. 2 is a perspective side view of a cross section of the detector of the invention.

[0013] FIG. 3 is a block diagram representing the conversion of an analog signal produced in the detector to a digital signal.

[0014] FIG. 4 is the graph of the spectral distributions of the energies of the electrons striking the scintillator crystal coated with 100 nm gold plating.

[0015] FIG. 5 is a graph of the spectral distributions of the energies of the electrons striking the uncoated scintillator crystal.

DESCRIPTION OF THE REFERENCES IN THE DRAWINGS

[0016] The numbers in the drawings are provided below in order to provide a better understanding of the invention: [0017] 100 Detector [0018] 1. Data output line [0019] 2. Column input [0020] 3. Gas inlet [0021] 4. Gas outlet [0022] 5. Gas mixing area [0023] 6. Gas inlet line [0024] 7. Scintillator crystal [0025] 8. Coating [0026] 9. Source [0027] 10. Shielding material [0028] 11. Gas outlet line [0029] 12. Fixing apparatus [0030] 13. Measurement chamber [0031] 14. Outlet chamber [0032] 200 Electronic Mechanism [0033] 15. First unit [0034] 16. Second unit [0035] 17. First power source [0036] 18. Second power source [0037] 19. Photodetector [0038] 20. Optical signal processing unit [0039] 21. Electrical signal unit [0040] 22. Optical signal amplifier [0041] 23. Electrical signal amplifier [0042] 24. Analog to digital converter [0043] 25. Electronic circuit

DETAILED DESCRIPTION OF THE INVENTION

[0044] In one embodiment of the invention, the detector (100) of the invention comprises at least one data output line (1) in connection with an electronic mechanism (200), at least one column input (2), which is connected to the detector outlet column of a gas chromatography device and to which a sample from which the chromatography data is to be obtained is sent, at least one gas inlet (3) so that preferably nitrogen gas can enter, at least one gas outlet (4) for a gas to exit from the detector (100), at least one gas mixing area (5) for mixing the gas sent from the column inlet (2) and preferably N.sub.2 gas sent from the gas inlet (3), at least one radioactive measurement chamber (13), at least one gas inlet line (6) for transferring the gas to said radioactive measurement chamber (13), at least one light emitting source (9), preferably at least one shielding material (10) that prevents gases from exiting the shielding area, at least one gas outlet line (11) for the gas to exit from said radioactive measurement chamber (13), at least one scintillator crystal (7), over which the electrons pass and the photons which are released from the interaction hit and which ensures the formation of light signals at visible wavelengths and ultraviolet (UV) wavelengths, at least one fixing apparatus (12) that carries the data of the light coming from the fiber optic cable inside the scintillator crystal (7) using a photodetector placed on the surface thereof, fixes the scintillator crystal (7) and transfers the electrical data from the scintillator crystal (7) to the data output line (1), and preferably at least one outlet chamber (14) to allow the gas to exit. In another embodiment of the invention, a non-radioactive source (9) is used in the detector (100) of the invention instead of the radioactive source (9). In this case, the chromatogram data is obtained by changing the geometric form of the measurement chamber (13).

[0045] Preferably, the electrical signal in the photodetector unit, which will read the light on the scintillator crystal (7) is formed by the current applied by a first power source (17) due to the optical photons falling on the photodetector. In addition, the scintillator crystal (7) interacts with the gases which are mixed in the said measurement chamber (13), and also allows the formation of an optical signal by emitting photons which has specific emission wavelengths as a result of the gases with which it interacts and of the current applied to the photodetector unit, or without the application of any current. Thus, both electrical and optical signals are generated.

[0046] In one embodiment, the outer surface of the scintillator crystal (7) may be uncoated. In another embodiment, the outer surface of the scintillator crystal (7) is coated with a conductive coating (8) which has a predetermined thickness. In said embodiment, in addition to the optical signal, the electrical signal is also obtained over the conductor, wherein the corrosion which will occur on the scintillator crystal (7) is prevented and the signal of low energy electrons is separated from the optical signal.

[0047] The gas chromatography device to be used in the invention comprises the detector (100) of the invention and at least one electronic mechanism (200) which processes the optical/electrical signals coming from said detector and forms the spectrum thereof.

[0048] In another embodiment of the invention, the detector (100) of the invention comprises at least one data output line (1) in connection with an electronic mechanism (200), at least one column input (2), which is connected to the detector outlet column of a gas chromatography device and to which the gas to be measured is sent, at least one gas inlet (3) so that preferably nitrogen gas can enter, at least one gas outlet (4) for gas to exit from the detector (100), at least one gas mixing area (5) for mixing the gas sent from the column inlet (2) and preferably N.sub.2 gas sent from the gas inlet (3), at least one radioactive measurement chamber (13), at least one gas inlet line (6) for transferring the gas to said radioactive measurement chamber (13), at least one source (9), at least one shielding material (10) that prevents the gas from exiting the radioactive area, at least one gas outlet line (11) for the gas to exit from said radioactive measurement chamber (13), at least one scintillator crystal (7), over which the electrons pass and the photons which are released from the interaction hit and which ensures the formation of light signals at visible wavelengths and ultraviolet wavelengths, a conductive coating (8) of the predetermined thickness which is coated onto the scintillator crystal, at least one fixing apparatus (12) that carries the data of the light coming from the fiber optic cable inside the said coating (8), fixes the scintillator crystal (7) and transfers the electrical data coming from the coating (8) to the data output line (1), and at least one outlet chamber (14) to allow the gas to exit.

[0049] The gas supplied to the gas inlet (3) is preferably N.sub.2 gas, however it is not limited thereto in practice.

[0050] In one embodiment of the invention, the scintillator (or scintillation) crystal (7) is used in the detector (100) of the invention without any coating. In said embodiment, the scintillator crystals (7) may be YAP (Ce) or YAG (Ce) or LYSO or CdWO4 and Nal (TI) or CaF.sub.2. However, it is not limited to these materials and different scintillation materials can be used. In another embodiment of the invention, the scintillator (or scintillation) crystal (7) comprises a conductive coating (8) which has a high conductivity at a predetermined thickness value. Said conductive coating (8) is metals with a high conductivity, such as gold, platinum, silver, but in practice it is not limited thereto. The above-mentioned conductive coating (100) has preferably a thickness of 100 nm. The spectrum obtained is a characteristic feature caused by the internal structure of the scintillator. The spectral data obtained in the invention is made less noisy/is improved by using the coating (8) on the scintillator crystal (7).

[0051] In order to measure the data in the detector (100) of the invention, an electronic mechanism (200) is used, which is coupled to an output line (1). Said electronic mechanism (200) comprises at least one first unit (15) for carrying the light coming through the scintillator crystal (7) over the fiber optic cable or directly processing it without a fiber optic, at least one second unit (16) receiving the electrical data coming through the conductor on which the scintillator crystal (7) is coated or directly through the scintillator crystal (7), at least one first power source (17) applying (or electrically feeding) a current to the second unit (16), thereby to the coating, at least one photodetector (19) which converts the light data into the electrical signal, at least one second power supply (18) used to display the optical data in a photodetector, preferably in a photomultiplier (PMT), at least one optical signal processing unit (20), where said photomultiplier (19) signal is amplified, at least one electrical signal unit (21) which amplifies the electrical signal coming through the conductive coating (8), at least one optical signal amplifier (22) for the signal from said photomultiplier (19), at least one electrical signal amplifier (23) for the signal from the conductive coating (8), at least one high-speed analog-to-digital converter (24) with separate input for both signals (optical and electrical), and at least one electronic circuit (25) for collecting the data.

[0052] Said column inlet (2) is connected to the detector outlet column of a gas chromatography device, and the gas flows from the gas inlet (3) together with the gas flowing from the column. The gas which will flow from the gas inlet (3) can be nitrogen or another preferred gas. The gas flowing from the column inlet (2) and from the gas inlet (3) flows to the gas mixing area (5) by mixing. In the gas mixing area (5), the pressures of the gases mix depending on the ambient temperature, and the entry is realized through the channels indicated by the gas inlet line (6) to the chamber indicated by the measurement chamber (13) in which the radioactive area is concentrated. The gases are prevented from leaving the radioactive area thanks to the shielding material (10).

[0053] The electron particles are randomly emitted from the surface indicated by the position indicated by the source (9). The free particles first interact with the conductive coating (8) and generate an electrical signal. The gain obtained from the electrons trapped on the conductive coating (8) can be adjusted according to the voltage applied from the power source (17) to the conductive coating (8) or directly to the scintillator crystal (7). The electrons passing through the conductive coating (8) and the photons released from the interaction of said electrons and the gas hit the scintillator crystal (7) and form the light signals in visible and ultraviolet wavelengths on the scintillator crystal (7).

[0054] The electric current formed in the conductive coating (8) and the luminescence level formed in the scintillator crystal (7) change in proportion to the energy lost by the particles coming from the source (9) due to the gas which they encounter in the measurement chamber (13).

[0055] The incoming gas flows to the outlet chamber (14) through the channels indicated by the gas outlet line (11), and then the gas is discharged by leaving this chamber from the gas outlet (4).

[0056] The data obtained from the conductive coating (8) and/or the scintillator crystal (7) starts to be processed to be directed to the electronic mechanism (200), which is the data acquisition system, through the data output line (1). It proceeds as a fiber with the first unit (15) and is connected to the photomultiplier (19). The photomultiplier (19) is controlled by the second power source (18), and the light signal is converted into the electrical signal and proceeds to the optical signal unit (20). The data output line (1) the gain of which is controlled by the first power source (17) and the electrical signal coming from the coating (8) proceed to the electrical signal unit (21). A pre-amplification process for both signals which come as the electric current in the optical signal unit (20) and the electrical signal unit (21) is performed, and they are directed to the optical signal amplifier (22) and the electrical signal amplifier (23). In order to convert both signals from analog to digital, an amplification is performed in the optical signal amplifier (22) and the electrical signal amplifier (23). The signals proceed to the analog-to-digital converter (24). In the analog-to-digital converter (24), both signals are analyzed separately and converted into a digital signal, and the digital signal generation process is completed in the electronic circuit (25) to form the chromatogram data. Therefore, the optical and electrical signal coming from the detector (100) is amplified/filtered by said electronic mechanism (200), and the spectrum thereof is obtained.

[0057] It has been made possible to use the ECD system with the scintillation method thanks to the scintillator crystal (7) which is used in the invention. The use of the scintillation technique in the ECD method allows a measure which is more sensitive than the conventional methods in the gas analysis. The use of the scintillation technique also allows the use of the different radioactive sources in the gas chromatography instead of the Ni.sup.63 source which is generally used.

[0058] The corrosion which would be formed by the gas measured in the gas chromatography will be reduced by the conductive coating (8). Since the coating (8) consists of a highly conductive material, it can be used as a second data source.

[0059] The anode which is made of the materials such as copper and brass in the state of the art is converted (or evolved) into the scintillator crystal (8). Once the detector (100) of the invention herein begins to be used in a gas chromatography, the scintillator crystal (7) contained therein is coated with a conductive material depending on the content of the gases passing there through, as there may be corrosion, pollution, contamination and the reduced accuracy and the precision of the data. However, when the scintillator crystal (7) is coated with materials such as gold, etc., some data acquisition advantages can be achieved, and accordingly, the obtained spectra can be better.

[0060] In the graphs given in FIG. 4 and FIG. 5, the situation between the scintillator crystal (7) coated with 100 nm gold coating such that there is air in the gas chamber and the uncoated scintillator crystal (7) is displayed, and the spectral distributions of the energies of the electrons striking the scintillator crystal (7) are shown in the both graphs. In both simulations, the situation created by the electrons with an output energy of 66 keV at 1 MBq activity in the same geometric system for a period of one second was examined.

[0061] 346.291 of the 1.000.000 electrons formed in the graph in FIG. 4 directly reached the scintillator crystal (7), and an average of 51.32 keV energy was measured (including the electrons striking at low energies). In the graph in FIG. 5, 100 nm gold coating (8) was applied to the scintillator crystal (7), and it was observed that 206.694 electrons hit the scintillator crystal (7). Despite that there is approximately 40% less of electron strike compared to the simulation in FIG. 4, the average value (59.19 keV) closer to the output energy of the electrons was observed in the energy information. The reason for the difference is that low energy electrons are trapped within the gold coating (8). In this way, it is seen that the low-energy electrons are filtered out at the measured average electron energy for the same medium. This filtering can also be examined as the decrease in the number of data with the gold coating (8) for values less than 30 keV (average) on the x-axis of the graphs. Briefly, the information that the low energy electrons will be blocked with 100 nm gold coating (8) and a decrease in the parasitic signal formation will be observed is simulated in the graphics.

Industrial Applicability of the Invention

[0062] The invention is a detector (100) which comprises a scintillator crystal (8) to enable precise measurements to be made in the gas chromatography that can be used in the industry and which is industrially applicable.

[0063] The invention is not limited to the above exemplary embodiments, and a person skilled in the art can easily reveal the different embodiments of the invention. These should be considered within the scope of protection of the invention claimed in the claims.