We installed new grating to your Renishaw inVia Raman microsscope. While routine calibration of the system, we observed the Si raman peak at 515cm-1 for 532 lase 600 grating and 519.9 cm-1 for 532 laser and 1800 grating. Why does the system shows different peak value by changing the grating? We mostly use 1800 grating so have not encountered this problem earlier. Any idea ? or suggestion if i can correct it somehow
Basically this means the gratings are calibrated slightly differently. Probably at original installment they calibration was identical, but now it has drifted. The calibration is basically the assignment of Pixel on your CCD to a certain wavenumber.
Your software should provide an option to calibrate your system. The calibration usually drifts over time, ie. components slowly drift out of their original position due to temperature changes, time etc. Also, when you change the gratings they usually never end in exactly the same position. Which is a very normal thing. Simply use a well known type of sample, your silicon is a good candidate, because the peak of silicon is very well known (if you check literature it will probably be reported at 520.8 or similar) and recalibrate it.
Basically this means the gratings are calibrated slightly differently. Probably at original installment they calibration was identical, but now it has drifted. The calibration is basically the assignment of Pixel on your CCD to a certain wavenumber.
Your software should provide an option to calibrate your system. The calibration usually drifts over time, ie. components slowly drift out of their original position due to temperature changes, time etc. Also, when you change the gratings they usually never end in exactly the same position. Which is a very normal thing. Simply use a well known type of sample, your silicon is a good candidate, because the peak of silicon is very well known (if you check literature it will probably be reported at 520.8 or similar) and recalibrate it.
There should be an option to manually offset the peak position to the standard position which for us with a 2400 grating is 520.5 and for a 600 grating is 520.7.
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