Advantage and Experience of Windowless X-ray Energy Dispersive Spectroscopy at Composition Analysis of Fluorescent Sample and Lithium Metal
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摘要: 用扫描电子显微镜搭载的有窗X射线能谱仪(EDS能谱)对荧光样品进行分析时,由于电子束的激发作用,样品受激自发产生的荧光将严重干扰EDS能谱探头对特征X射线的分析,最终导致定量困难甚至难以定性. 新型无窗EDS能谱由于其优异的低能量端信号采集与分析能力,结合单颗粒小区域采集的方法,可以成功实现荧光样品的正常EDS能谱分析. 由于无窗EDS能谱仪没有传统薄膜窗口的吸收作用,其最低可分析元素为锂. 通过优化加速电压,并借助样品表面钝化膜的保护作用,克服了背景噪音与样品污染的干扰,成功实现对单质锂的检测.Abstract: When the fluorescent samples were analyzed using a windowed X-ray energy dispersive spectrometer (EDS) equipped with a scanning electron microscope, due to the excitation of the electron beam, the stimulated fluorescence by sample stimulation will seriously interfere with the analysis of the characteristic X-rays by the EDS energy spectroscopy probe, which leads to qualitative and quantitative difficulties. The new windowless EDS combined with the method of single particle small region acquisition can successfully achieve normal EDS spectral analysis of fluorescent samples because of its excellent low-energy-end signal acquisition and analysis capability. Without the adsorption of the traditional ultra-thin window, the windowless EDS can analyze lithium metal. By optimizing the accelerating voltage and the protective effect of the passivation film on the sample surface, the interference of background noise and sample contamination were overcome, and the detection of elemental lithium was successfully realized.
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Key words:
- EDS /
- windowless EDS /
- fluorescent samples /
- lithium metal
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图 1 有窗EDS能谱在15 kV加速电压下分析两种荧光粉得到的异常EDS能谱图
(a)铈掺杂钇铝石榴石荧光粉的EDS能谱图,(a-1)为其荧光发射光谱图,(b)铕掺杂氮化物荧光粉的EDS能谱图,(b-1)为其荧光发射光谱图
Figure 1. Abnormal EDS spectra of two fluorescent powder samples obtained by windowed EDS at 15 kV
(a) EDS spectrum of Y3Al5O12:Ce, (a-1) fluorescence spectrum of Y3Al5O12:Ce, (b) EDS spectrum of SrAlSiN3:Eu, (b-1) fluorescence spectrum of SrAlSiN3:Eu
图 2 电子束加速电压和采集区域大小对铈掺杂钇铝石榴石荧光粉EDS能谱分析的影响
(a-1) ~ (c-1)分别为大区域采集下电子束加速电压为15、10和5 kV时的EDS能谱图,(a-2) ~ (c-2)分别为单颗粒采集下电子束加速电压为15、10和5 kV时的EDS能谱图
Figure 2. Effect of accelerating voltages and scanning areas on EDS spectra of Y3Al5O12:Ce
(a-1) ~ (c-1) accelerating voltages of 15, 10 and 5 kV, respectively, focused on large scanning area, (a-2) ~ (c-2) accelerating voltages of 15, 10 and 5 kV, respectively, focused on single particle
图 4 不同条件下锂峰的出峰与峰形
(a)电子束加速电压为5 kV时样品表面氧化严重,电子束加速电压为(b)1 kV,(c)10 kV,(d)5 kV时受表面钝化膜保护的样品,电子束加速电压为(e)3 kV,(f)5 kV时样品表面经过长时间电子束辐照
Figure 4. Emergence and shape of peaks of lithium under different conditions (a) severely oxidized samples of surfaces under 5 kV, samples protected by passivation films under (b) 1 kV, (c) 10 kV, (d) 5 kV, sample areas of surfaces under repeated radiation by electron beam under (e) 3 kV, (f) 5 kV
表 1 有窗EDS能谱在不同电子束加速电压下对铈掺杂钇铝石榴石荧光粉的定量分析结果
Table 1. Compositional analysis of Y3Al5O12:Ce by windowed EDS under different accelerating voltages
/% Y重量分数 Al重量分数 O重量分数 Ce重量分数 Y∶Al∶O原子比
(理论值1∶1.67∶4)15 kV大区域 Null Null Null Null Null 10 kV大区域 100 0 0 0 Null 5 kV大区域 51.0 22.0 24.0 2.9 1∶1.42∶2.64 15 kV单颗粒 51.0 24.1 23.1 1.0 1∶1.55∶1.78 10 kV单颗粒 48.0 23.1 27.4 1.5 1∶1.52∶1.64 5 kV单颗粒 48.3 21.3 28.9 1.5 1∶1.44∶3.30 表 2 铈掺杂钇铝石榴石荧光粉和铕掺杂氮化物荧光粉的无窗EDS能谱定量分析结果
Table 2. Compositional analysis of Y3Al5O12:Ce and SrAlSiN3:Eu analyzed by windowless EDS
/% 物质 元素 质量分数 原子
百分比Y3Al5O12∶Ce(Y∶Al∶O原子比理论值为1∶1.67∶4) Y 41 13.1 Al 22.5 23.6 O 35.6 63.1 Ce 0.9 0.2 SrAlSiN3∶Eu(Sr∶Al∶Si∶N原子比理论值为1∶1∶1∶3) N 23.7 50.1 Al 16 17.5 Si 16.9 17.8 Sr 42.1 14.3 Eu 1.3 0.3 -
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