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xmuxiaoyu

金虫 (著名写手)


[交流] 【求助】请教用monochromator采集光谱的问题

最近要测量非常弱的光的光谱分布,用的是monachromator, 型号是triax 320,不知道大家有没有用过。首先用光电倍增管测量到光的强度大概是10万cps左右。如果将光源连接到monachromator的入口,但是什么也没有测量到,尽管曝光时间在一分钟左右。请问是什么问题呢?是不是因为monachromator的灵敏度不够。望大家多给意见,谢谢。
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bote

maybe you had to run through your monochromator over its wavelength range.

★ ★ ★ ★ ★ ★ ★ ★
xmuxiaoyu(金币+1,VIP+0):谢谢指点 9-17 03:38
musi429(金币+2,VIP+0):多谢交流~ 9-17 03:38
xmuxiaoyu(金币+5,VIP+0):谢谢 9-17 21:30
or if you've already known the light source wavelength, then set the monochromator around it and make a narrow scan.

首先用光电倍增管测量到光的强度大概是10万cps左右

As your 光电倍增管 can pick up photons from your light source, then, you may use it to get the spectroscopy of your light source by replacing the installed PIN detector on your spectrometer.
Another approach is:
1. checking the background noise of your spectrometer w/o any light in. This may help you to estimate the sensitivity of your spectrometer, and then compared it with that of your PMT.
2. if the sensitivity is compatible, then your light source may be of wide band, and light intensity at each wavelength is too weak to be measurable.
3. if the sensitivity of your spectrometer is only a little bit worse, you may still be able to get the spectroscopy by (a) conducting several measurements and then averaging them. (b) increasing the shutter-open time based on the noise ratio.  

All suggestion above is based on that you have run your spectrometer at its best for your sample such as its PIN detector at 77 K, the right grating installed (the lowest resolution grating), the greatest slit and the fastest F#. Good luck.


我的monochromator是用CCD 作为detector
1. You can use "bin or binning" setting in your software to combine several pixels of your CCD together for increasing its sensitivity (at the expense of sacrificing its resolution).   
2. the exit slit may be not allowed to be adjusted. You may consult the vendor about all your questions.

光投射不到ccd上面
if other people have used your spectrometer for similar measurements, it seems that light can reach CCD sensor.

[ Last edited by bote on 2009-9-18 at 12:01 ]
2楼2009-09-17 03:28:01
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xmuxiaoyu

金虫 (著名写手)


我已经用了很宽的波长扫描范围了,从400到1300nm,
我不知道光源的波长,估计峰在700nm左右,高手,指点啊
3楼2009-09-17 03:38:08
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xmuxiaoyu

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非常感谢bote的指点
我的monochromator是用CCD 作为detector,用液氮冷却,按理应该是很灵敏的,因为很多实验室都用这台仪器。
我的仪器有四个ports,我发现entrance port的宽带可以改变的,通过电脑控制,从0-2mm,但是exit port的宽带改变不了,一直是0.我不知道是不是因为这个原因,光投射不到ccd上面。
4楼2009-09-17 21:29:53
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