Page 4 - Shimadzu MXF-2400
P. 4

Principle                                                                                                                  Construction








            When X-rays hit a sample, atoms in the sample are excited and release the secondary X-rays, which are also called fluorescent X-rays.
            Since the wavelength of secondary X-rays is peculiar to the element concerned, the sample can be qualitatively determined by measuring
            that wavelength. Also, since the fluorescent X-ray intensity is proportional to the concentration of the element, quantitative
            determination is made by measuring the fluorescent X-ray intensity of the wavelength peculiar to each element.
                                                                                                                                                                                        1

                                                             Focusing circle
                                              Detector  X-ray tube
                                                                         Detector
                                          Secondary slit                                                                                                                                    2
                                                                         Secondary slit                                                                                             3
                                         2θ 2
                                                                          2θ 2                                                                                       6
                                     Curved crystal
                                                                       Curved crystal                                                                                           4                       7
                                                               Primary slit
                                                Primary slit
                                                        Sample
                                                      Concentration
                                       Concentration (%)  calculation   X-ray intensity (kcps)                                                                                                          8
                                        Si  3.1182                  Si  34.79725
                                        Mn  0.2011    Intensity     Mn  6.30588
                                        P   0.0209                  P   0.45881                                                                                                        5
                                        S   0.0173                  S   1.11912
                                        Mg  0.0185     Concentration  Mg  0.11576
                                                                                                                                                                                                         9


            Spectrometer Unit                                  Measuring Electronics

            This unit disperses the fluorescent X-rays generated from the   The electric pulses corresponding to the number of X-ray photons
            sample, measures the intensity of the X-rays of the particular   are counted and recorded. — The output pulse signal of the
                                                                                                                                       1  X-ray Spectrometer (Installed in the case)      6  Data Processing Unit
            wavelength, and converts that intensity into electric signals. High   detector is amplified and its interfering spectrum signals are
            quality curved crystals are used for dispersion.   removed by the pulse height analyzer. Then the signal is measured      Up to 36 monochromators are radially arranged around   The operation of the MXF-2400 is made via the keyboard
                                                                                                                                      the X-ray tube. The case of the X-ray spectrometer is   of this unit. This unit has various high-level data handling
            The MXF-2400 uses one monochromator for one element, and up   by the scaler, processed by the microprocessor, and then
                                                                                                                                      temperature-controlled.                            functions, which provides advanced analysis by easy
            to 36 monochromators can be installed together to permit   transmitted to the data processing unit.
                                                                                                                                                                                         operation.
            simultaneous determination of up to 36 elements.
                                                                                                                                       2  Sample Turntable (with dust-proof cover)
            Use of the optional scanning monochromator provides automatic                                                                                                                 7  X-ray Power Control Unit and
            qualitative analysis and allows up to 30 elements to be preset for                                                        Up to eight samples may be loaded together for        Processor Unit
            quantitative analysis.                                                                                                    automated successive analysis. An external automatic
                                                                                                                                      sample feeder and/or automatic sample pretreatment unit   The X-ray power control unit controls the output power
                                                                                                                                      may be connected to this turntable.                of the X-ray tube with such a high stability that it is not
            X-ray Power Source                                 Data Processing Unit                                                                                                      necessary to use a motor generator in most cases. The
                                                                                                                                       3  Sample Feeding Unit                            processor unit incorporates the X-ray intensity measuring
            This unit supplies power to the X-ray tube which emits the   X-ray intensities are converted into concentration values of the
                                                                                                                                        (Installed behind the panel)                     circuit and the microprocessor, which counts X-ray pulses
            excitation X-rays (primary X-rays). It consists of a high-voltage   elements concerned through the use of the conversion equations                                           and controls all the other units.
            transformer and an X-ray power controller.         (calibration curves) predetermined using standard samples. The         The swing arm system accurately positions the sample.
                                                               results are presented on the display or the printer.                                                                       8  DC Power Source Unit
                                                                                                                                       4  Maintenance Panel
                                                                                                                                                                                         This unit supplies DC power to the control units.
                                                Spectrometer                                                                          This unit displays the status of each part and has manual
                                                unit
                                                                                                                                      switches for checking.
                                                                 Measuring electronics  Data processing unit
                                                 Mono-                                                                                                                                    9  Switchboard
                                                                        Microprocessor  Keyboard                                       5  X-ray Tube Cooling Unit                        The necessary power source is one three phase 200 VAC
                                                 chro-                         Display
                                      X-ray power source  meter  Detector
                                                                                Printer
                                                                 PHA scaler                                                           This unit circulates cool, distilled water to the X-ray tube.   or 220 VAC line.
                                                 X-ray tube  Amplifier
                                                                                                                                      The distilled water is cooled externally.
                                                                                                                                                                                                                            MXF-2400
                                                                                                                                                                                                                     Multi-Channel X-ray Fluorescence Spectrometer
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