Uranium isotope abundance measurement method by using carbon nanotubes as ion emission agent

A technology of isotopic abundance and carbon nanotubes, which is used in measurement devices, preparation of samples for testing, and material analysis by electromagnetic means. The effect of increased efficiency, reduced coating volume, and improved stability

Active Publication Date: 2013-04-10
NUCLEAR POWER INSTITUTE OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If thermal ionization mass spectrometry is used to measure nanogram-level uranium samples, the signal value is small at low temperature, but at high temperature, the sample volatilizes quick

Method used

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  • Uranium isotope abundance measurement method by using carbon nanotubes as ion emission agent
  • Uranium isotope abundance measurement method by using carbon nanotubes as ion emission agent

Examples

Experimental program
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Effect test

Embodiment 1

[0023] The measurement method disclosed in the present invention is mainly composed of three major steps of sample preparation, sample coating and sample measurement, and the three steps are now described in detail.

[0024] (1) Sample preparation: including the preparation of carbon nanotube suspension and the pretreatment of rhenium tape, among which:

[0025] Preparation of carbon nanotube suspension: Weigh three parts of 0.1g carbon nanotubes into 100ml plastic bottles, add 50ml deionized water with a resistivity >18MΩ.cm, and ultrasonically disperse for 20 minutes to form a uniform suspension Standby, if it has not been used for a long time, it needs to be ultrasonically dispersed before use.

[0026] Pretreatment of rhenium ribbons: (a) Degassing treatment: Degas the rhenium-rhenium double-belt inserts in the degassing device to remove moisture and impurities. Combined composition, its size is 0.04×0.7×18mm, the evaporation rhenium belt is used to provide the evaporatio...

Embodiment 2

[0040] The only difference between this example and Example 1 is that in step (2) of this example, the carbonized evaporated rhenium strip is placed on the applicator, and 1 μL of uranium solution is dropped on the sample applicator with a micropipette. In the center of the evaporated rhenium band, slowly increase the temperature of the evaporated rhenium band to 300°C and dry it, then disconnect the current, wait until the evaporated rhenium band drops to room temperature, take 1 μL of carbon nanotube suspension and coat it on the uranium sample, slowly raise Evaporate the rhenium strip at 180°C to dry a large amount of water, then raise it to 300°C for drying, and finally raise it to 400°C for 10 seconds, disconnect the current, take the sample strip down to room temperature, and put it on the sample together with the ionization strip On the turntable to be tested.

[0041] In step (3), put the installed turntable into the ion source, turn on the mass spectrometer, and perfo...

Embodiment 3

[0044] The only difference between this example and Example 1 is that in step (2) of this example, the carbonized evaporated rhenium strip is placed on the applicator, and 1 μL of uranium solution is dropped on the sample applicator with a micropipette. In the center of the evaporated rhenium band, slowly increase the temperature of the evaporated rhenium band to 350°C and dry it, then disconnect the current, wait until the evaporated rhenium band drops to room temperature, take 1 μL of carbon nanotube suspension and coat it on the uranium sample, slowly raise Evaporate the rhenium tape at 220°C to dry a large amount of water, then raise it to 350°C for drying, and finally raise it to 450°C for 20 seconds, disconnect the current, take the sample tape down to room temperature, and put it on the sample together with the ionization tape On the turntable to be tested.

[0045] In step (3), put the installed turntable into the ion source, turn on the mass spectrometer, and perform ...

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Abstract

The invention discloses a uranium isotope abundance measurement method by using carbon nanotubes as an ion emission agent, which comprises the following steps: (1) sample preparation: preparing a carbon nanotube suspension, and pretreating a rhenium strip; (2) sample coating: putting the evaporation rhenium strip on a sample coating device, dripping a uranium solution onto the evaporation rhenium strip, drying, and cooling to room temperature; coating the carbon nanotube suspension on the uranium sample, drying the evaporation rhenium strip, cooling to room temperature, and loading onto a rotary table; and (3) sample measurement: sending the rotary table into an ion source, starting a mass spectrometer, and after the ion current signal intensity reaches the maximum and the signal stays in the most stable state for 3-5 minutes, starting data acquisition of uranium isotope abundance measurement. By using the carbon nanotubes as the ion emission agent for uranium isotope abundance measurement, the invention improves the ion emission property of trace uranium sample in thermal ionization mass spectrometer measurement; and by optimizing the burning strip used by the carbon nanotubes as the emission agent as well as experimental conditions for sample preparation, testing and the like, the invention establishes a novel method for measuring the abundance of trace uranium isotope.

Description

technical field [0001] The invention relates to the field of measuring uranium isotope abundance, in particular to a method for measuring uranium isotope abundance using carbon nanotubes as ion emitters. Background technique [0002] Thermal surface ionization mass spectrometry is one of the most accurate and commonly used methods for measuring uranium isotope abundance, and is widely used in uranium ore exploration, geological research, and nuclear fuel element burnup measurement. Because the ionization efficiency of uranium is not high, in order to obtain accurate isotope abundance measurement results, the sample amount is generally on the order of micrograms. If thermal ionization mass spectrometry is used to measure nanogram-level uranium samples, the signal value is small at low temperature, but at high temperature, the sample volatilizes quickly and the signal is unstable (high at first, but quickly decays to zero). It is quickly depleted, making it difficult to measu...

Claims

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Application Information

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IPC IPC(8): G01N27/64G01N1/28
Inventor 李已才梁帮宏张劲松陈云明张舸杜文鹤
Owner NUCLEAR POWER INSTITUTE OF CHINA
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