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荧光分析
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"Figure 2.30 shows the time-resolved luminescence of Eu2+-doped Sr2Si5N8 measured at varying delay times." 我在文献中看到的这段话，我做的是荧光粉，然后不明白，在荧光分析中为什么要测delay time？ |
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6楼2012-03-19 22:51:12
2楼2011-11-30 14:42:40
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小木虫(金币+0.5):给个红包，谢谢回帖
comehappyon(金币+2): 这个太抽象了，实在看不明白。 2011-12-01 08:46:13
小木虫(金币+0.5):给个红包，谢谢回帖
comehappyon(金币+2): 这个太抽象了，实在看不明白。 2011-12-01 08:46:13
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Delay Lines Delay lines, or a way to introduce time delays, are incorporated into all TCSPC instruments. The need for delay lines is easily understood by recognizing that there are significant time delays in all components of the instrument. A photoelectron pulse may take 20 ns to exit a PMT. Electrical signals in a cable travel a foot in about 1 ns. It would be difficult to match all these delays within a couple of nanoseconds in the start and stop detector channels without a way to adjust the delays. The need for matching delays through the components is avoided by the use of calibrated delay lines. Such delays are part of the NIM bin electronics. However, lengths of coaxial cable are prone to picking up RF interference. Calibrated delay lines are also useful for calibration of the time axis of the MCA. This is accomplished by providing the same input signal to the start and stop channels of the TAC. The preferred approach is to split an electrical signal, typically from the start detector, and direct this signal to both inputs of the TAC. Since the pulses arrive with a constant time difference, one observes a single peak in the MCA. One then switches the time delay in the start or stop channel by a known amount, and finds the peak shift on the MCA display. By repeating this process for several delay times, the TAC and MCA can be calibrated. 自己多看几次，估计能看明白 |
3楼2011-11-30 15:47:43
4楼2011-11-30 16:17:48
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