SU1187040A1 - Method of x-ray radiometric ore sampling - Google Patents

Description

The invention relates to nuclear-physical analysis of the elemental composition of complex substances and can be used to test the composition of objects with a complex surface shape, 5 for example, broken rock mass, or ORE transported in containers.

The purpose of the invention is to improve the performance of testing and the elimination of false results. ten

Fig, 1 shows a diagram of the device for implementing the method; in fig. 2 - instrumental line of scattered radiation at three positions of the surface of the ore to be tested; in figure 3 15 the error signal _? generated by a spectrum position analyzer.

The proposed method is based on a physical phenomenon consisting in shifting the position of the maximum of the peak 20 of the scattered test ore - collimated radiation with a change in the ore - radiation detector, since the main radiation fraction is scattered in the subsurface py-25 d, the change of the specified distance '. scattering angle

Θ and, thereby, the energy of the · scattered radiation,

The method is implemented as follows.

Before testing, the probe is installed at a certain distance from the surface of the ore, depending on. the size of the transport capacity with the ore being tested.

The ore is irradiated with X-ray or Y radiation from source 1, and the detector 2 records streams of scattered and characteristic radiation of the determined elements, which determine their content in the ore. The analyzer 3 determines the displacement of the maximum position of the instrumental scattered radiation line caused by the probe probe being tested by changing the distance, producing an error signal A ^> (Fig. 3), if the probe is not installed at the required distance from the surface of the test ore 50. The error signal is supplied in the mechanism 4 move the probe and, depending on the error signal, lower or raise the probe as long as there is an error signal, 55 i.e. until the probe is installed at a predetermined distance from the ore being tested. Then they give permission to block 5 to perform calculations of the content of components in the ore and to read the results of testing.

Example. For the excitation of the characteristic radiation of the elements being analyzed, the radiation of the source based on the cobalt-57 nuclide is used, and for the excitation of singly scattered radiation - the radiation of the cesium-137 source. Secondary radiation is recorded with a scintillation detector. Characteristic lines analyzed elements tested analyzer pulse amplitudes AI-256, offset photopeak energy scale ore scattered radiation with an energy of 662 keV is determined from the difference between signals from two discriminators are configured symmetrically with respect to the nominal _peak: SG distance (position "0"'of FIG. 2) between the surface of the ore and the probe. The differential signal is amplified and fed to the electric motor of the actuator that moved the probe vertically up and down, depending on the polarity of the error signal, until the nominal distance between the probe and the ore to be tested is established.

When the distance between the sensor (probe) and the ore is varied, the photopeaks of the scattered radiation shift along the energy scale. The displacement of the photopeak (maximum) of the scattered radiation on an energy scale is determined relative to the nominal (pre-specified) energy value E ^, which corresponds to a certain distance H _o between the sensor and the ore being tested. When this distance is set equal (Fig. 1), the photo peak of the scattered radiation coincides with the position of E _o (Fig. 2), the error signal at the output of the analyzer 3 is missing, the sensor does not move with the executive mechanism 4, and the processing unit 5 gives the test results .

P nominal distance _of between the sensor and corresponds approximately ore singly scattered quanta energy E _o as defined by Compton ^:

E,

^ 0 1 + (1 - cos θ ^)

3

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where is the energy of primary γ-quanta;

. 1 - electron rest energy

(0.511 meV);

θο is the single scattering angle of 5 Y-quanta.

When the distance between the sensor and the ore before the scattering angle is increased to b _n and the energy of singly scattered photons yu decrease creases and takes on the energy scale the position of E ^. With a decrease in the sensor-ore distance to b & the scattering angle decreases to θ _β , and the energy once scattered in рассе-quan <5 tons increases and occupies the position Е _β .

At an ore irradiation angle of 45 °, i.e., when the probe length is equal to

the distance between the sensor and the ore, the shift of the photopeak of the scattered radiation is approximately proportional to the change in the distance of the sensor - ore by 10 - 15%. Reducing the irradiation angle, i.e. elongation of the probe, increases the displacement of the peak of the scattered radiation, approximately ^ as L / g ^ ° C, where about - the angle of irradiation.

The automatic retention of the measuring probe at a predetermined distance from the ore surface eliminates the operations required in the known device for finding the inversion region and setting the probe into this region, and therefore increases the testing performance and eliminates false counts.

Claims (1)

X-ray radiometric RUNDING method using a probe containing sources and a radiation detector consisting in irradiating the test ore with collimated x-ray or gamma radiation from a radiation source, detecting the intensity of the characteristic X-ray radiation of the detected elements and scattered radiation, which determine the desired contents, differing by that, in order to improve the performance of testing and eliminate false results, determine the bias The position of the maximum of the scattered radiation instrumental line, which occurs when the distance from the probe to the surface of the ore to be tested is changed, is moved vertically along the probe to compensate for the position of the maximum of the instrumental scattered radiation line, after which the measurement result is read. WITH $ 1 1187040 2