A method and device for preparing samples for measuring total alpha and total beta radioactivity

Abstract

The present invention relates to a method and device for preparing samples for measuring total alpha and total beta radioactivity, comprising: step S1: in a U-shaped screen, grinding balls and the U-shaped screen fit each other and can rotate relatively to apply a rolling pressure to a concentrated or processed solid sample to be tested, and based on the rolling pressure, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested; step S2: after adding anhydrous ethanol to the ash sample to be tested, it is stirred in a sample tray to form a paste; step S3: rotating the sample tray, and a scraper parallel to the sample tray is used to make the ash sample to be tested into a sample source to be tested with a uniform and flat thickness in a manner that the height of the scraper and the sample tray can limit the thickness of the sample source to be tested.

Description

Technical Field

[0001] The invention relates to the technical field of radioactivity measurement, in particular to a sample preparation method and device for measuring total alpha and total beta radioactivity. Background Art

[0002] Total α and total β radioactivity refers to the total radioactivity level of α and β radionuclides in the sample. Since the content of radionuclides is usually very low, the measurement of total α and total β radioactivity usually requires that water, biological, aerosol, soil and other samples be concentrated or processed into solid substances in advance, ground into fine ash (an important prerequisite for uniform sample spreading), and then evenly spread on the sample plate to make a sample source (measurement source, sample source), and then sent to the low-background α and β measuring instrument to measure and record the counts caused by the α particles and β particles emitted by the sample source that pass through the sample source itself, the air layer between the sample source and the detector, and the detector entrance window and enter the detector and still have a certain energy. Finally, the measurement results are compared with the measurement results of the standard source (reference source) made of standard substances under the same conditions under the same measurement conditions to obtain the total α and total β radioactivity levels of the sample. The measurement of total α and total β radioactivity is essentially a relative measurement, and the conditions of the sample source and the standard source must be almost completely consistent. At present, the grinding of the concentrated or processed solid sample to be tested and the flattening of the ash sample to be tested are all done manually by the experimenters, which is not only time-consuming and laborious, but also cannot ensure that the concentrated or processed solid sample to be tested is fully ground, and cannot ensure that the thickness of the prepared sample source and the standard source is uniform and flat, especially for infinitely thin or extremely thin (0.5-5 mg / cm 2 )’s sample source and standard source.

[0003] For example, a Chinese patent with publication number CN1103200072A discloses a sample source preparation device and method for measuring total α and total β in water, which includes a suction pump, a suction filter bottle, and a filtering device. The suction filter bottle is connected to the suction pump, and the filtering device is inserted into the suction filter bottle, and the filtering device has filter paper. The filtering device includes a filter cartridge and a filter head, and the filter head is inserted into the suction filter bottle. The filter cartridge is detachably connected to the top of the filter head. A sieve plate and filter paper are arranged in the filter head, and the filter paper is placed on the sieve plate. The purpose of the invention is to provide a sample source preparation device and method for measuring total α and total β radioactivity in water, so as to solve the problem that the uniformity of the sample source plate preparation for measuring total α and total β radioactivity in water in the prior art is greatly disturbed by human subjective factors, so as to achieve the purpose of ensuring that the sample source plate is uniform and flat, and improving the quality of the sample source for water sample measurement. However, the device is only used for samples in which the sample is liquid, and cannot be used to prepare samples in which the sample is solid.

[0004] Compared with nuclide analysis, total α and total β radioactivity measurement has the advantages of short cycle, low cost, simplicity and ease of operation. In addition, the level of radionuclides in the environment is very low in most cases, and the health hazards are extremely limited. Generally, there is no need for nuclide analysis. Therefore, total α and total β radioactivity are widely used in radioactive contamination screening, that is, the total α and total β radioactivity of the sample is first determined, and when the total α and total β radioactivity levels exceed the screening level or the preset operation level, the nuclide analysis is performed. The World Health Organization and many countries use total α and total β radioactivity as drinking water radioactivity screening indicators, and the International Atomic Energy Agency uses total α and total β radioactivity as radioactivity screening indicators for food, milk and drinking water in nuclear and radiation accident emergencies. Accurately measuring the total α and total β radioactivity levels of samples can avoid unnecessary nuclide analysis. At present, many technicians have conducted a lot of research on various factors that affect the accurate measurement of total α and total β radioactivity and have given corresponding solutions, but no practical method has been given for how to prepare sample sources and standard sources with uniform thickness to reduce counting errors.

[0005] In solid matter, alpha particles and low-energy beta particles have a very short range. If it is not infinitely thin (such as 0.5 mg / cm 2 ), then the α particles and low-energy β particles emitted by it are easily absorbed or lose energy due to the interaction with the solid material itself. This is the self-absorption of α particles and β particles. For the measurement of total α and total β radioactivity, in order to ensure the measurement sensitivity and convenient sample preparation, the sample source and the standard source usually have a certain thickness (usually 10-20 mg / cm 2 ), its self-absorption of α particles and low-energy β particles cannot be ignored. Due to the existence of self-absorption, most α particles and β particles are absorbed or their energy is reduced, and only a few α particles and β particles on the surface of the sample source and the standard source can be ejected and recorded by the low-background α and β measuring instrument. Generally, the thicker the solid material, the more serious the self-absorption of α particles and β particles. If the thickness distribution of the sample source and the standard source is uneven and flat, the self-absorption of α particles and β particles in various parts of the sample source and the standard source will be inconsistent, so the uniformity and flatness of the thickness of the sample source and the standard source seriously affects the counting efficiency of the low-background α and β measuring instrument for α particles and β particles (especially α particles). Since the absorption of α particles and β particles by the air layer between the sample source or the standard source and the detector and the detector incident window or the energy loss of α particles and β particles is fixed, whether the thickness of the sample source and the standard source is uniform and flat has a great influence on the accuracy of the total α and total β radioactivity measurement results. Summary of the invention

[0006] In view of the deficiencies of the prior art: A method for preparing samples for measuring total α and total β radioactivity, comprising: grinding a concentrated or processed solid sample to be tested into a ash sample to be tested with a mesh size that meets the requirements, preparing the ash sample to be tested into a sample source to be tested with a relatively uniform and flat thickness, step S1: in a U-shaped screen, grinding balls and the U-shaped screen fit each other and can rotate relative to each other to apply a crushing pressure to the concentrated or processed solid sample to be tested, based on the crushing pressure, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested; step S2: after adding anhydrous ethanol to the ash sample to be tested, stirring it in a sample tray to form a paste, step S3: rotating the sample tray, and preparing the ash sample to be tested into the sample source to be tested in a manner such that the height of the scraper blades parallel to the sample tray can limit the thickness of the sample source to be tested.

[0007] According to a preferred embodiment, a large number of ash samples to be tested are concentrated in the middle area of ​​the sample tray, so that when the sample tray rotates, the ash samples to be tested can be driven to rotate by the scraping wire thickening area of ​​the rigid scraping wire, so that the ash samples to be tested are driven by the scraping wire thickening area to creep toward the two sides of the scraping wire side area based on the centrifugal force and the scraping action of the scraping wire thickening area.

[0008] According to a preferred embodiment, as the sample disc rotates, the ash sample to be tested in the middle area of ​​the sample disc gradually creeps to the scraping wire side area under the action of centrifugal force and the scraping block of the scraping wire thickening area, and is gradually spread evenly under the smoothing action of the scraping bottom.

[0009] According to a preferred embodiment, both ends of the rigid scraping wire are respectively connected to the inner spiral rod via at least two oblique wires, wherein the torsional stiffness of the oblique wires is greater than the torsional stiffness of the rigid scraping wire, so that the rigid scraping wire can flatten the ash sample to be tested in a controllable shaking manner during the rotation of the rotating disk.

[0010] According to a preferred embodiment, the inner spiral rod is spirally connected to the outer spiral rod, and the outer spiral rod is spirally connected to the outer fixed tube, wherein the pitch of the inner spiral rod is smaller than the pitch of the outer spiral rod, so that the height between the scraper and the sample plate can at least be determined by first coarse adjustment and then fine adjustment.

[0011] According to a preferred embodiment, the inner screw is provided with a sensor, and the rotation speed of the sample disk can be determined based on a measurement signal of the sensor.

[0012] According to a preferred embodiment, in step S3, a bubble level meter is used to check whether the sample tray is in a horizontal state.

[0013] According to a preferred embodiment, the method comprises: step S4, turning on an infrared lamp to dry the sample source to be tested with a uniform and flat thickness.

[0014] According to a preferred embodiment, the present invention also provides a sample preparation device for measuring total α and total β radioactivity, which at least includes a U-shaped screen, grinding balls, a sample tray and a scraper. In the U-shaped screen, the grinding balls and the U-shaped screen fit each other and can rotate relative to each other to apply a crushing pressure to the concentrated or processed solid sample to be tested. Based on the crushing pressure, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested; after adding anhydrous ethanol to the ash sample to be tested, it is stirred in a sample tray to form a paste, and the sample tray is rotated. The scraper parallel to the sample tray makes the ash sample to be tested into the sample source to be tested in a way that the height of the two can limit the thickness of the sample source to be tested.

[0015] According to a preferred embodiment, the scraper blade includes a rigid scraper wire, and the rigid scraper wire includes a scraper wire thickening area and a scraper wire side wing area, wherein the scraper wire thickening area increases in the thickness direction from the scraper bottom to the scraper top, and after reaching a maximum value at the symmetry axis of the scraper blade, decreases in the thickness direction from the scraper bottom to the scraper top and is located in the middle of the scraper wire side wing areas on both sides. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a sample spreader of a total α and total β measurement sample preparation device provided by the present invention;

[0017] Figure 2 is a schematic diagram of a scraper of a total α and total β measurement sample preparation device provided by the present invention; and

[0018] Figure 3 is a schematic diagram of a sample grinder of a total α and total β measurement sample preparation device provided by the present invention; and

[0019] Figure 4 It is a preferred rigid scraping wire provided by the present invention;

[0020] Figure 5 It is a schematic flow chart of the method of the present invention.

[0021] Reference numerals list

[0022] 100: Sample grinder 200f: Leveling base

[0023] 200: Sample spreader 200g: Level bubble meter

[0024] 200a: Sample tray 200h: Backing plate

[0025] 200b: scraper 200i: rotating disk

[0026] 200c: Height adjuster 200b-1: Rigid scraper

[0027] 200c-1: Inner spiral rod 100a: Sample grinder bracket

[0028] 200c-2: External spiral rod 100b: Fixed sleeve

[0029] 200c-3: External fixing tube 100c: Rotating screw

[0030] 200c-4: Sample laying support 100d: Handle

[0031] 200c-5: inner screw rod fixing knob 100e: connecting rod

[0032] 200c-6: External screw rod fixing knob 100f: U-shaped screen

[0033] 200d: tablet clamp 100g: grinding ball

[0034] 200e: Bottom plate 200b-2: Oblique wire drawing

[0035] 200b-1a: scrape bottom 200b-1c: scrape top

[0036] 200b-1b: scraping wire flank area 200b-1d: scraping wire thickening area

[0037] 300: Infrared light DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-5 Provide detailed explanation.

[0039] In the present invention, the sample has at least the following three forms, which include, in order of processing steps:

[0040] For the solid sample to be tested, water, biological, aerosol, soil and other samples are first concentrated or processed into the solid sample to be tested.

[0041] The ash sample to be tested is prepared by grinding the concentrated or processed solid sample to be tested into the ash sample to be tested.

[0042] For the sample source to be tested, drop a small amount of anhydrous ethanol into the ash sample to be tested and stir it into a paste, then spread it evenly and dry it to form a sample source that can be measured by the measuring probe.

[0043] In the present invention, since total α and total β are relative measurement values, a reference sample is required during measurement. Therefore, the sample source to be measured includes a sample source) and a standard source (made with a reference sample).

[0044] Example 1

[0045] This embodiment discloses a method for measuring total α and total β radioactivity in grinding samples.

[0046] The sample preparation device includes a sample grinder 100 and a sample spreader 200. The sample grinder 100 is used to grind the concentrated or processed solid sample to be tested into a gray sample to be tested that meets the sample preparation mesh requirements of the sample spreader 200. Specifically, the sample grinder 100 includes the following components:

[0047] The sample grinder bracket 100a is made of 304 stainless steel, with a diameter of 4mm and a length of 70mm. It is welded to the middle of the upper part of the fixed sleeve 100b, forming an angle of 30 degrees with it, and is used to support the fixed sleeve 100b and fix the weighing paper for collecting the ash sample to be tested after grinding.

[0048] The fixed sleeve 100b is made of 304 stainless steel, with an upper length of 40mm, an upper inner diameter of 20mm, a lower length of 7mm, a lower inner diameter of 12mm, and a thickness of 2mm. A thread is set inside the sleeve with a pitch of 0.1mm, which is used to fix the rotating screw rod 100c and the U-shaped screen 100f.

[0049] The rotating screw 100c is made of 304 stainless steel, with a diameter of 20mm, a length of 50mm, and a pitch of 0.1mm. The upper side is connected to the handle 100d, and a screw hole with a diameter of 4mm and a depth of 4mm is set in the middle of the bottom end, which is connected to the connecting rod 100e.

[0050] The handle 100d is made of 304 stainless steel, has a length of 40 mm and a diameter of 4 mm, and is connected to the rotating screw 100c.

[0051] The connecting rod 100e is made of 304 stainless steel, with a diameter of 4mm and a length of 38mm. It is provided with threads at both ends, with the upper thread length of 4mm and the lower thread length of 3mm. It is connected to the rotating screw 100c and the grinding ball 100g respectively.

[0052] The U-shaped sieve 100f is made of 304 stainless steel, with a thickness of 1mm, an inner diameter of 10mm, a length of 35mm, a smooth inner wall, a hemispherical bottom, a sieve hole located at the bottom of the hemispherical bottom, a sieve hole of 100 mesh, and a 5mm long thread set on the outer side of the upper end, which is connected to the bottom of the fixed sleeve 100b.

[0053] The grinding ball 100g is made of 304 stainless steel, is hemispherical, has a diameter of 10mm, a smooth spherical surface, and a screw hole with a diameter of 4mm and a depth of 3mm is set in the center of the upper part, which is connected to the connecting rod 100e. When the rotating screw 100c is rotated to the upper bottom end of the fixed cylinder 100b, the grinding ball 100g is completely consistent with the bottom end of the U-shaped screen 100f.

[0054] At least one optional workflow of the sample grinder 100 is: transfer the concentrated or processed solid sample to be tested into the U-shaped screen 100f in the grinder 100, screw the U-shaped screen 100f and the fixed sleeve 100b together, place the weighing paper under the U-shaped screen 100f, press it with the sample grinder bracket 100a, push the handle 100d by hand to rotate the screw 100c until the grinding ball 100g and the U-shaped screen 100f are completely matched, rotate the screw 100c, flick the U-shaped screen 100f with fingers several times, and then push the handle 100d by hand to rotate the screw 100c until the grinding ball 100g and the U-shaped screen 100f are completely matched, repeat several times, and fully grind the concentrated or processed solid sample to be tested into the gray sample to be tested. After the sample is ground, remove the U-shaped screen 100f and the grinding ball 100g, clean them with ultrapure water and anhydrous ethanol, and dry them for standby use.

[0055] Example 2

[0056] This embodiment discloses a method for measuring total α and total β radioactivity.

[0057] The inventor of the present invention has conducted a long-term investigation and research on the existing devices and processes. The main problems of the existing manual production include at least: 1. It is impossible to ensure that the thickness of the sample source and the standard source is uniform and flat, especially when the amount of ash sample to be tested is small or the thickness is infinitely thin or extremely thin (0.5-5 mg / cm 2 ) It is extremely difficult to prepare a uniform and flat sample source. Due to the self-absorption of α particles and β particles, the thickness of the sample source to be tested is uneven after preparation, which has a great impact on the measurement results of total α and total β radioactivity. 2. In the process of manually flattening the sample source to be tested, the sample source is easy to crawl outward to the outer edge of the sample tray, and it is easy to contaminate the probe during the measurement process, resulting in an increase in the background of the low-background α and β measuring instrument, thereby affecting the accuracy of the total α and total β radioactivity measurement results. Therefore, this embodiment mainly provides a total α and total β radioactivity measurement sample preparation device, which aims to quickly and conveniently prepare sample sources and standard sources with uniform and flat thickness, and the prepared sample sources and standard sources will not crawl outward to contaminate the probe. Furthermore, the sample preparation device provided in this embodiment is to improve the accuracy of total α and total β radioactivity detection and the stability of the measurement value. Specifically:

[0058] This embodiment discloses a sample preparation device for measuring total α and total β radioactivity. The sample preparation device includes a sample spreader 200, which is used to prepare the gray sample to be tested into a sample source to be tested with a relatively uniform thickness. Specifically, the sample spreader 200 includes a sample plate 200a and a scraper 200b. Figure 1 and 2 As shown, the sample plate 200a and the scraper 200b are arranged in parallel, and the height difference between the two defines the thickness of the sample source to be tested. Generally, the thickness of the sample source to be tested is 0.5-50 mg / cm2 . The inventor of the present invention finely adjusts the thickness of the sample source to be tested, on the one hand to ensure that the thickness of the sample source to be tested is relatively uniform and flat, and on the other hand to ensure that the sample source to be tested can still be made into a uniform and flat sample source even when the thickness is infinitely thin or extremely thin. Infinitely thin means that the sample source to be tested is observed by the human eye as a thin film, thereby reducing the interaction between α particles and β particles and solid matter and reducing absorption or energy loss, so as to overcome the technical problem in the prior art that the sample source to be tested cannot be made infinitely thin or extremely thin with uniform thickness due to manual production, thereby solving the technical problem that the sample source to be tested made by the prior art has a large thickness, resulting in excessive absorption of α particles and β particles by itself.

[0059] In this embodiment, the scraper 200b and the sample disk 200a can rotate relative to each other, so that the gray sample to be tested on the sample disk 200a after being stirred with anhydrous ethanol can rotate relative to the scraper 200b. The scraper 200b contacts the gray sample to be tested during the rotation of the sample disk 200a relative to it. Based on the centrifugal force and the contact force of the scraper 200b, the gray sample to be tested is gradually spread out and flattened, and the height of the scraper 200b and the gray sample to be tested is gradually adjusted. The rotating disk 200i drives the sample disk 200a to rotate until it forms a relatively uniform and flat sample source to be tested. At this time, the maximum thickness that the sample source to be tested can reach is the height difference between the sample disk 200a and the scraper 200b, and the prepared sample source to be tested is roughly a pancake-shaped thin sheet (similar to a film). By comparing the sample source to be tested made by the present invention (sample source No. 1) with the handmade sample source to be tested (sample source No. 2) under the same experimental conditions, it was found that: since sample source No. 1 is thinner, sample source No. 1 is more easily detected by a low-background α and β measuring instrument, so that the measured value of sample source No. 1 is closer to the true value and has greater reference value; since sample source No. 1 is more uniform, when the same batch of solid samples to be tested are prepared and measured, the total α and total β radioactivity values ​​of sample source No. 1 show higher stability (i.e., smaller standard deviation), which fully demonstrates that the measured value of the sample source to be tested made by the sample preparation device provided by the present invention has more scientific value and guiding significance.

[0060] In addition, in addition to the above considerations on the accuracy and stability of the measured values, the present invention reduces the labor and energy of the experimenter (or measurement personnel) as much as possible. On the one hand, the more accurate and stable the measured values ​​are, the less the experimenter (or measurement personnel) need to make and measure the sample repeatedly; on the other hand, by using the device, the flattening and making process of the sample source to be measured is almost completely completed by the device, so that the experimenter (or measurement personnel) does not need to spend much energy and time in the sample making process.

[0061] Preferably, if Figure 2As shown, the scraper 200b includes a rigid scraping wire 200b-1 for making the gray sample to be tested into a sample source to be tested. The rigid scraping wire 200b-1 plays a role similar to "wire cutting" and "leveling" the gray sample to be tested during the relative rotation of the sample disk 200a. In the early stage of relative rotation, the gray sample to be tested is uneven, and the rigid scraping wire 200b-1 gradually drives the part higher than it to the part of the sample disk 200a corresponding to the sample disk 200a that is not covered with the gray sample to be tested or is lower than it in a manner similar to "wire cutting", gradually making the surface formed by the gray sample to be tested just contact with the rigid scraping wire 200b-1, and then based on the centrifugal force and the contact of the rigid scraping wire 200b-1, the gray sample to be tested is gradually leveled until it is relatively evenly spread out. In the present invention, the rigid scraping wire 200b-1 is fixedly connected to the height adjuster 200c. According to the thickness requirement of the sample source to be tested, the height adjuster 200c adjusts the rigid scraping wire 200b-1 to the thickness requirement, and places the stirred ash sample to be tested roughly and evenly in the center of the sample tray 200a. The length of the rigid scraping wire 200b-1 matches the sample loading diameter size of the sample tray 200a to prevent the ash sample to be tested from climbing to the outer edge of the sample tray 200a during the relative rotation process, thereby preventing the background radioactivity from increasing.

[0062] Preferably, if Figure 1 As shown, the height adjuster 200c includes an inner screw rod 200c-1 and an outer screw rod 200c-2. The inner screw rod 200c-1 is screwed to the outer screw rod 200c-2. The outer screw rod 200c-2 is screwed to the outer fixed cylinder 200c-3. Figure 2 As shown, the rigid scraping wire 200b-1 is fixedly connected to the inner spiral rod 200c-1. Preferably, the pitch of the inner spiral rod 200c-1 is smaller than the pitch of the outer spiral rod 200c-2. In this way, when the outer spiral rod 200c-2 is rotated until the scraper 200b is close to the gray sample or standard substance to be tested, the outer spiral rod 200c-2 is fixed with the outer spiral rod fixing knob 200c-6, and then the inner spiral rod 200c-1 is rotated until the scraper 200b contacts the gray sample or standard substance to be tested, the inner spiral rod 200c-1 is fixed with the inner spiral rod fixing knob 200c-5. Therefore, the height between the scraper 200b and the sample disk 200a can be finely adjusted by first coarse adjustment and then fine adjustment, thereby ensuring that the sample source to be tested can be as infinitely thin as possible.

[0063] Preferably, the rigid scraping wire 200b-1 is connected to the inner spiral rod 200c-1 by at least two oblique edges. Figure 1 and 2As shown, the rigid scraping wire 200b-1 is connected to the inner spiral rod 200c-1 by two oblique edges, so that the scraper 200b forms a stable triangular structure. The two oblique edges are also made of stainless steel wires of comparable size. In the process of the rigid scraping wire 200b-1 contacting the gray sample to be tested, based on the stable structure of the triangle, the rigid scraping wire 200b-1 relatively smoothly (there may be some shaking, especially in the early stage of sample laying) performs "wire cutting" and "leveling" on the gray sample to be tested. Through careful measurement results, it is found that: if the rigid scraping wire 200b-1 is not connected to the inner spiral rod 200c-1 by the oblique edge but connected to the inner spiral rod 200c-1 by a T-type, the flatness of the sample source to be tested formed at this time is lower (but still higher than that made by hand), and the stability of its measured value is also lower (but still higher than that made by hand).

[0064] Example 3

[0065] This embodiment may be a further improvement and / or supplement to Embodiments 1 and 2, and repeated contents will not be repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may be used as a supplement to this embodiment.

[0066] This embodiment provides a sample preparation device for measuring total α and total β radioactivity, and the specific components required include:

[0067] Sample laying bracket 200c-4: used to support the inner spiral rod 200c-1, the outer spiral rod 200c-2 and the outer fixed tube 200c-3, with a diameter of 10mm and a length of 200mm, perpendicular to the upper surface of the base plate 200e, and made of 304 stainless steel.

[0068] Bottom plate 200e: 200mm long, 200mm wide, 10mm high, a 304 stainless steel cylinder with a diameter of 60mm and a height of 5mm is set in the center of the upper surface, and the material is 304 stainless steel.

[0069] Leveling base 200f: located below the bottom plate 200e, the leveling base 200f can be adjusted to ensure that the rotating disk 200i / bottom plate 200e is in a horizontal state.

[0070] Rotating disk 200i: rotates around the cylinder on the bottom plate 200e, used to drive the sample disk 200a to rotate relative to the scraper 200b, with a diameter of 100mm, a height of 10mm, a concave depth of 5mm at the center of the lower surface, a diameter of 60mm, and is made of 304 stainless steel.

[0071] Pressing clamp 200d: located on the rotating disk 200i, used to fix the sample disk 200a.

[0072] The backing plate 200h is located on the rotating disk 200i and is used to backing the sample disk 200a. Its outer diameter is 60mm, which is 1mm concave than the upper surface of the rotating disk 200i. Its inner diameter is 54mm, which is 3mm concave than the upper surface of the rotating disk 200i.

[0073] Level bubble meter 200g: located on the rotating disk 200i, used to check whether the rotating disk 200i / bottom plate 200e is in a horizontal state;

[0074] The rigid scraping wire 200b-1 is a filament with a smooth surface. Its diameter is 0.2mm-0.5mm, and its length matches the sample diameter size of the sample disk 200a. Preferably, the scraper 200b is an equilateral triangle made of 316 stainless steel wire with a diameter of 0.3mm, the bottom side (rigid scraping wire 200b-1) is parallel to the rotating disk 200i, the length of the bottom side (rigid scraping wire 200b-1) matches the sample diameter size of the sample disk 200a, and the top is connected to the inner spiral rod 200c-1 by a nut through a 316 stainless steel wire with a diameter of 0.3mm. According to the currently commonly used sample disk 200a sample diameter size of 20mm, 30mm, 45mm and 52mm, scrapers with bottom sides (rigid scraping wire 200b-1) lengths of 20mm, 30mm, 45mm and 52mm can be made to meet the needs of sample preparation of sample disks 200a with different sample diameters.

[0075] The infrared lamp 300 is used to dry the laid sample source and standard source. It has a rated power of 50W and adjustable power. The lamp head emits parallel infrared light. The cross-sectional area of ​​the parallel infrared light is slightly larger than the sample plate 200a. The heating temperature in the heating area is relatively uniform and stable.

[0076] Inner screw rod fixing knob 200c-5: Made of plastic, used to fix the inner screw rod 200c-1, and fix the inner screw rod 200c-1 so that it does not rotate when the rotating disk 200i is rotated to lay the sample source or standard source.

[0077] Outer screw rod fixing knob 200c-6: Made of plastic, used to fix the outer screw rod 200c-2, and fix the outer screw rod 200c-2 so that it does not rotate when the rotating disk 200i is rotated to lay the sample source or standard source.

[0078] The outer spiral rod 200c-2 is hollow, with threads both inside and outside, a pitch of 1mm, an outer diameter of 5mm, an inner diameter of 2mm, perpendicular to the rotating disk 200i / bottom plate 200e, and is made of 304 stainless steel.

[0079] The inner screw rod 200c-1 is provided with a thread, a pitch of 0.1 mm, a diameter of 2 mm, is perpendicular to the rotating disk 200i / bottom plate 200e, and is made of 304 stainless steel.

[0080] The sample plate 200a has an outer diameter of 60mm and a thickness of 0.7mm. Its diameter (sample loading diameter) matches the rigid scraper 200b-1 and the probe size of the low-background α and β measuring instrument, which are usually 20mm, 30mm, 45mm and 52mm, with a net depth of 1.5mm, a flat surface, uniform thickness, and a polished surface. It is made of 304 stainless steel. After the preparation of the sample source to be tested is completed, the sample source to be tested laid on the sample plate 200a can be directly used for measurement by the measuring probe after being dried by an infrared lamp. The sample plate 200a is in a horizontal state. The thickness of the prepared sample source to be tested is relatively uniform and flat, and the liquid phase in the ash sample to be tested will not flow to the outer edge of the sample plate 200a when the scraper 200b and the sample plate 200a rotate relative to each other, thereby preventing it from contaminating the probe and further preventing it from increasing the background.

[0081] When using this device:

[0082] (1) First check the bubble level 200g, adjust the leveling base 200f to ensure that the rotating disk 200i / bottom plate 200e is in a horizontal state, and then take an appropriate amount of the ash sample or standard substance to be tested and put it into the sample tray 200a according to the measurement requirements. Place the sample tray 200a on the backing plate 200h and fix it with the pressing clamp 200d, drop a small amount of anhydrous ethanol, and use a pin to mix the ash sample or standard substance to be tested into a paste (thin mud) and spread it roughly evenly.

[0083] (2) Rotate the outer screw rod 200c-2 until the scraper 200b is close to the ash sample or standard substance to be tested, and then use the outer screw rod fixing knob 200c-6 to fix the outer screw rod 200c-2, then rotate the inner screw rod 200c-1 until the scraper 200b contacts the ash sample or standard substance to be tested, and then use the inner screw rod fixing knob 200c-5 to fix the inner screw rod 200c-1, and slowly rotate the rotating disk 200i to scrape the ash sample or standard substance to be tested flat, and repeat this process several times to make the scraper 200b contact the ash sample or standard substance to be tested and then scrape it flat until the ash sample or standard substance to be tested is evenly spread. Preferably, the rotating disk 200i can be manually rotated by the experimenter to drive the sample disk 200a to rotate relative to the scraper 200b.

[0084] (3) Finally, the infrared lamp 300 is turned on to dry the gray sample or standard material to be tested in the sample tray to form a sample source or standard source with uniform thickness.

[0085] Example 4

[0086] This embodiment may be a further improvement and / or supplement to Embodiment 1, 2 or a combination thereof, and repeated contents are not repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may be used as a supplement to this embodiment.

[0087] Preferably, the relative rotation speed of the scraper 200b and the sample disk 200a is configured in a manner of first slowing down, then gradually increasing, and then gradually slowing down to a uniform speed. The rotating disk 200i of the present embodiment is driven by a motor. The speed of the motor is first set by laboratory personnel in a controller, such as a PLC controller. The inventors found in the study of the effect of rotation speed on the measured value that in the process of "wire cutting" of the gray sample to be measured by the rigid scraper 200b-1, its rotation speed is as slow as possible. If it is too fast, the liquid phase in the sample source to be measured is easily separated from the solid phase, thereby affecting its measurement result. After the gray sample to be measured is gradually evenly spread out, the rotation speed can be appropriately increased to increase the centrifugal force so that the gray sample to be measured is as thin as possible. Subsequently, the rotation speed of the sample disk 200a is reduced to maintain a uniform rotation in order to make the flatness of the sample source to be measured higher, that is, the thickness of the sample source to be measured is as uniform as possible during the uniform speed process.

[0088] Example 5

[0089] This embodiment may be a further improvement and / or supplement to one of Embodiments 1, 2, 3 or a combination thereof, and repeated contents are not repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may be used as a supplement to this embodiment.

[0090] This embodiment discloses a preferred scraper blade 200b. The scraper blade 200b includes a rigid scraper wire 200b-1 and an oblique wire 200b-2 (ie, an oblique edge) for fastening the rigid scraper wire 200b-1.

[0091] Preferably, the rigid scraper wire 200b-1 includes a scraper wire thickening area 200b-1d and a scraper wire flank area 200b-1b. Figure 4 As shown, the scraper wire thickening area 200b-1d is located in the middle of the scraper wire wing area 200b-1b on both sides in a manner that the thickness increases from the scraper bottom 200b-1a to the scraper top 200b-1c, and after reaching the maximum value at the symmetry axis of the scraper blade 200b, the thickness decreases from the scraper bottom 200b-1a to the scraper top 200b-1c. In addition, the area where the thickness increases and decreases is limited to the area near the symmetry axis of the scraper blade 200b. And, preferably, as Figure 4As shown, the scraping wire thickening area 200b-1d is formed in the following manner: the scraping bottom 200b-1a always maintains a constant height relative to the sample disk 200a in the direction from the scraping wire wing area 200b-1b on one side to the scraping wire wing area 200b-1b on the other side, and the scraping top 200b-1c first increases relative to the height of the sample disk 200a in the direction from the scraping wire wing area 200b-1b on one side to the scraping wire wing area 200b-1b on the other side, and then decreases after reaching a maximum value at the symmetry axis of the scraper 200b. Preferably, the scraping top 200b-1c is designed to be streamlined. The scraping bottom 200b-1a, as an important part for leveling the gray sample to be tested, always remains relatively parallel to the sample disk 200a, so the scraping bottom 200b-1a is a straight line in the front projection direction. Preferably, the trend of increase or decrease is smooth rather than abrupt.

[0092] When laying the sample, the gray sample to be tested is placed in the middle area of ​​the sample tray 200a, which is almost corresponding to the scraping wire thickening area 200b-1d. When the sample tray 200a rotates, a large number of gray samples to be tested are concentrated in the scraping wire thickening area 200b-1d and piled up. At this time, the scraping wire thickening area 200b-1d acts as a baffle to drive more gray samples to be tested in the middle area to rotate. Based on the centrifugal force and the scraping and blocking effect of the scraping wire thickening area 200b-1d, the gray sample to be tested driven by the scraping wire thickening area 200b-1d creeps to the two sides of the scraping wire wing area 200b-1b. As the sample tray 200a rotates, the gray sample to be tested in the middle area of ​​the sample tray 200a gradually creeps to the scraping wire wing area 200b-1b under the centrifugal force and the scraping and blocking effect of the scraping wire thickening area 200b-1d, and is gradually spread evenly (relatively evenly) under the leveling effect of the scraping bottom 200b-1a. This structure of the scraper wire 200b-1 is: on the one hand, in order to improve the production efficiency of the sample source to be tested, the scraper wire thickened area 200b-1d can pull more gray samples to be tested to rotate relative to it and creep to both sides with centrifugal force, reducing the time for the gray samples to be tested to move to both sides, thereby improving efficiency; on the other hand, although the rigid scraper wire 200b-1 is a component made of steel, it is actually flexible due to its slenderness. The provision of the scraper wire thickened area 200b-1d increases the rigidity coefficient of the rigid scraper wire, which can keep its vibration at a reasonable amplitude and frequency as much as possible to promote the movement of the gray samples to be tested to both sides.

[0093] Example 6

[0094] This embodiment may be a further improvement and / or supplement to one of embodiments 1, 2, 3, 4, 5 or a combination thereof, and repeated contents are not repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may be used as a supplement to this embodiment.

[0095] This embodiment discloses a preferred scraper blade 200b. The scraper blade 200b includes a rigid scraper wire 200b-1 and an oblique wire 200b-2 (ie, an oblique edge) for fastening the rigid scraper wire 200b-1.

[0096] The rigid scraping wire 200b-1, as the name implies, is a filament made of a rigid material, such as 304 stainless steel. However, since the length of the rigid scraping wire 200b-1 is more than 20 mm, it is equivalent to a beam structure with both ends fixed, so it exhibits "flexibility" during contact with the gray sample to be tested, and then it will shake. After research, it was found that the shaking of the rigid scraping wire 200b-1 is greatly affected by the rotation speed, the flexibility of the oblique wire 200b-2, and the height of the suspension point of the oblique wire 200b-2. Furthermore, the inventor of the present invention found in the study that compared with the case where the torsional stiffness of the oblique wire 200b-2 is less than or equal to the torsional stiffness of the rigid scraping wire 200b-1, when the torsional stiffness of the oblique wire 200b-2 is greater than the torsional stiffness of the rigid scraping wire 200b-1, the shaking of the rigid scraping wire 200b-1 is controllable, and it is conducive to speeding up the flattening speed of the gray sample to be tested. Controllable means that in the initial stage when the rigid scraping wire 200b-1 contacts the gray sample to be tested, the shaking amplitude and shaking frequency of the rigid scraping wire 200b-1 are large, but the creeping speed of the gray sample to be tested to both sides increases, and then in the process of gradually flattening the gray sample to be tested, the shaking amplitude of the rigid scraping wire 200b-1 is significantly reduced and the shaking frequency is reduced until it stops shaking. The sample source to be tested is accelerated to flatten at a controlled shaking action of the rigid scraping wire 200b-1, and after being measured by a measuring instrument, the thickness of the sample source obtained by this method can meet the requirements of infinitely thin or extremely thin.

[0097] Preferably, a displacement sensor, a velocity sensor or an acceleration sensor, etc., which can measure the vibration of the inner spiral rod 200c-1, is provided on the inner spiral rod 200c-1. The measurement signal of the sensor can appropriately (qualitatively or semi-quantitatively) reflect the thickness of the sample source to be tested. When the signal measured by the sensor changes from irregular to regular, it means that the thickness of the sample source to be tested almost meets the measurement requirements. In this case, when the signal measured by the sensor is regular, the speed of the rotating disk 200i can start to decrease and uniformly speed to improve the quality of the sample source to be tested. Therefore, the present invention can measure the thickness of the sample source to be tested without setting too many image monitoring equipment and microscopic monitoring equipment, thereby saving the thickness detection process, improving the rate and efficiency of radioactive detection, and is particularly beneficial for detection in key nuclear areas such as nuclear test areas and nuclear leakage areas.

[0098] Example 7

[0099] This embodiment also discloses a sample preparation device, which may be a further improvement and / or supplement to one of embodiments 1, 2, 3, 4, 5, 6 or a combination thereof, and the repeated contents will not be repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may serve as a supplement to this embodiment.

[0100] This embodiment discloses a sample preparation device for measuring total α and total β radioactivity, comprising:

[0101] The sample grinder 100 grinds the concentrated or processed solid sample to be tested into a gray sample to be tested with a mesh size that meets the requirements;

[0102] The sample spreader 200 prepares the gray sample to be tested into a sample source to be tested with a relatively uniform thickness. The sample spreader includes a scraper 200b and a sample tray 200a. The scraper 200b and the sample tray 200a are parallel to each other. At this time, the height between the two is set according to the thickness requirement of the sample source to be tested. When the scraper 200b and the sample tray 200a rotate relative to each other, the scraper 200b can prepare the gray sample to be tested into a sample source to be tested with a relatively uniform thickness.

[0103] Preferably, the speed of the relative rotation of the scraper 200b and the sample plate 200a is configured in a manner of first slowing down, then increasing, and finally decreasing to a uniform speed.

[0104] Example 8

[0105] This embodiment also discloses a sample grinder, which can be a further improvement and / or supplement to one of the embodiments 1, 2, 3, 4, 5, 6, 7 or a combination thereof, and the repeated contents will not be repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments can be used as a supplement to this embodiment.

[0106] The sample grinder includes a U-shaped screen 100f and grinding balls 100g. In the U-shaped screen 100f, the grinding balls 100g and the U-shaped screen 100f fit each other and can rotate relative to each other to apply a grinding force to the concentrated or processed solid sample to be tested, and based on the grinding force, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested.

[0107] After adding anhydrous ethanol to the ash sample ground by the sample grinder, the sample is stirred in the sample tray 200a to form a paste. The sample tray 200a is rotated, and the scraper 200b parallel to the sample tray 200a forms the ash sample into a sample source in such a way that the height of the scraper 200b and the sample tray 200a can define the thickness of the sample source.

[0108] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention description and its drawings are illustrative and do not constitute a limitation of the claims. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing samples for measuring total α and total β radioactivity, comprising: Grind the concentrated or processed solid sample to be tested into a ash sample to be tested with a mesh size that meets the requirements. Prepare the ash sample to be tested into a sample source with relatively uniform thickness. It is characterized in that Step S1: In a U-shaped screen (100f), the grinding balls (100g) and the U-shaped screen (100f) fit each other and can rotate relative to each other to apply a grinding pressure to the concentrated or processed solid sample to be tested. Based on the grinding pressure, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested; Step S2: adding anhydrous ethanol to the ash sample to be tested and stirring in a sample tray (200a) to form a paste. Step S3: rotating the sample plate (200a), and using a scraper (200b) parallel to the sample plate (200a) to form the ash sample to be tested into the sample source to be tested in such a manner that the heights of the scrapers (200b) and the sample plate (200a) can define the thickness of the sample source to be tested; A large number of ash samples to be tested are concentratedly placed in the middle area of ​​the sample disk (200a), so that when the sample disk (200a) rotates, the ash samples to be tested can be driven to rotate by the scraping wire thickening area (200b-1d) of the rigid scraping wire (200b-1), so that the ash samples to be tested are driven by the scraping wire thickening area (200b-1d) to creep toward the two sides of the scraping wire flank area (200b-1b) based on the centrifugal force and the scraping effect of the scraping wire thickening area (200b-1d), and when the rigid scraping wire (200b-1) contacts the ash samples to be tested, the rigid scraping wire (200b-1) performs wire cutting and flattening on the ash samples to be tested, and the diameter of the rigid scraping wire (200b-1) is 0.2 mm to 0.5 mm; The relative rotation speed of the scraper (200b) and the sample plate (200a) is configured in a manner of first slowing down, then gradually increasing, and then gradually decreasing to a uniform speed. During the process of the rigid scraper (200b-1) performing wire cutting on the gray sample to be tested, its rotation speed is set in a manner of preventing the liquid phase and the solid phase in the sample source to be tested from being separated. Both ends of the rigid scraping wire (200b-1) are connected to the inner spiral rod (200c-1) via at least two inclined wires (200b-2), so that the scraping blade (200b) forms a stable triangular structure. The rigid scraping wire (200b-1) comprises a scraping wire thickening area (200b-1d) and a scraping wire flank area (200b-1b); The scraper wire thickening area (200b-1d) is located in the middle of the scraper wire flank area (200b-1b) on both sides in a manner that the thickness increases from the scraper bottom (200b-1a) to the scraper top (200b-1c), reaches a maximum value at the symmetry axis of the scraper blade (200b), and then decreases from the scraper bottom (200b-1a) to the scraper top (200b-1c), wherein: The ash sample to be tested is a fine ash-like solid material with the total radioactive level of α-radionuclide and β-radionuclide. The sample to be tested is a fine ash-like solid material. The thickness of the sample source to be tested is 0.5-5 mg / cm 2 .

2. The sample preparation method according to claim 1, characterized in that: As the sample plate (200a) rotates, the ash sample to be tested in the middle area of ​​the sample plate (200a) gradually creeps to the scraping wire side area (200b-1b) under the scraping action of the centrifugal force and the scraping thickening area (200b-1d), and is gradually spread evenly under the leveling action of the scraping bottom (200b-1a).

3. The sample preparation method according to claim 1, characterized in that: The torsional rigidity of the oblique drawing wire (200b-2) is greater than that of the rigid scraping wire (200b-1), so that the rigid scraping wire (200b-1) can flatten the gray sample to be tested in a controllable shaking manner during the rotation of the sample plate (200a).

4. The sample preparation method according to claim 3, characterized in that: The inner spiral rod (200c-1) is spirally connected to the outer spiral rod (200c-2), and the outer spiral rod (200c-2) is spirally connected to the outer fixed tube (200c-3). The pitch of the inner spiral rod (200c-1) is smaller than the pitch of the outer spiral rod (200c-2), so that the height between the scraper (200b) and the sample plate (200a) can at least be determined by first coarse adjustment and then fine adjustment.

5. The sample preparation method according to claim 3, characterized in that: The inner spiral rod (200c-1) is provided with a sensor, and the rotation speed of the sample disk (200a) can be determined based on a measurement signal of the sensor.

6. The sample preparation method according to claim 1, characterized in that: In step S3, a bubble level meter (200g) is used to check whether the sample tray (200a) is in a horizontal state.

7. The sample preparation method according to any one of claims 1 to 6, characterized in that: The method comprises: Step S4, turning on the infrared lamp (300) to dry the sample source to be tested with uniform thickness.

8. A sample preparation device for measuring total α and total β radioactivity, comprising at least a U-shaped screen (100f), a grinding ball (100g), a sample plate (200a) and a scraper (200b), It is characterized in that In the U-shaped screen (100f), the grinding balls (100g) and the U-shaped screen (100f) fit each other and can rotate relative to each other to apply a grinding force to the concentrated or processed solid sample to be tested, and based on the grinding force, the concentrated or processed solid sample to be tested is ground into an ash sample to be tested; After adding anhydrous ethanol to the ash sample to be tested, the mixture is stirred in a sample tray (200a) to form a paste. The sample plate (200a) is rotated, and a scraper (200b) which is parallel to the sample plate (200a) is used to form the ash sample to be tested into the sample source to be tested in such a manner that the height of the scraper (200b) and the sample plate (200a) can define the thickness of the sample source to be tested; A large number of ash samples to be tested are concentratedly placed in the middle area of ​​the sample disk (200a), so that when the sample disk (200a) rotates, the ash samples to be tested can be driven to rotate by the scraping wire thickening area (200b-1d) of the rigid scraping wire (200b-1), so that the ash samples to be tested are driven by the scraping wire thickening area (200b-1d) to creep toward the two sides of the scraping wire flank area (200b-1b) based on the centrifugal force and the scraping effect of the scraping wire thickening area (200b-1d), and when the rigid scraping wire (200b-1) contacts the ash samples to be tested, the rigid scraping wire (200b-1) performs wire cutting and flattening on the ash samples to be tested, and the diameter of the rigid scraping wire (200b-1) is 0.2 mm to 0.5 mm; The relative rotation speed of the scraper (200b) and the sample plate (200a) is configured in a manner of first slowing down, then gradually increasing, and then gradually decreasing to a uniform speed. During the process of the rigid scraper (200b-1) performing wire cutting on the gray sample to be tested, its rotation speed is set in a manner of preventing the liquid phase and the solid phase in the sample source to be tested from being separated. The rigid scraping wire (200b-1) comprises a scraping wire thickening area (200b-1d) and a scraping wire flank area (200b-1b); The scraper wire thickening area (200b-1d) is located in the middle of the scraper wire side wing area (200b-1b) on both sides in a manner that increases in the thickness direction from the scraper bottom (200b-1a) to the scraper top (200b-1c), reaches a maximum value at the symmetry axis of the scraper blade (200b), and then decreases in the thickness direction from the scraper bottom (200b-1a) to the scraper top (200b-1c).

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