Emission lines from the Deuterium lamp are split into two lines

Hi everyone,

We are using a UV-VIS-NIR model Cary 5000. Recently when we validated the instrument. However, at the wavelength accuracy test using the Deuterium lamp, we found that 486 and 656.1 nm emission lines have been split into two emission lines. However, when the instrument was just brought, there were only single emission lines (486 and 656.1 nm) from the Deuterium lamp as I would like to add the photos below.

These are emission lines that we currently validated our instrument


And these are emission lines from the Deuterium lamp when the instrument was new


Now, the wavelength accuracy test of our instrument has failed, and we can not use it.

Has any experienced this problem like us and why there are also more peaks near 486 and 656.1 nm?

Could this be due to our lamp or any other parts of our instrument has failed?

I would appreciate it if you could share with us your experience and solutions to address this problem.

Thank you very much.

  • Hello:


    The D2 lamp needs to be replaced.  The second line is hydrogen emission, due to the proximity of the deuterium emission can affect wavelength calibration. The lamps have a typical life of 500 hours.

    The lamp life is shown in the Align application.


    Open the Align application and choose the Lamps tab,

    Select source (e.g., UV) and the lamp hours are displayed on the right.

    Replace the vis lamp as well. 

    Align the lamps after replacement.


    Best regards,



  • Hi Mike,

    Thank you very much for providing us with very useful answers.
    We will follow your suggestions to fix our problem.

    Once again, I appreciate your support so much.

    Best regards,


  • Hi Mike,

    We have changed to a new D2 lamp, and there were no other peaks near the emission lines 468 and 656.1 nm. However, we got error messages in the following photo. I would like to share the photo of emission lines and error messages with you.

    This is emission line after we changed the D2 lamp

    And this is error messages that we still get.

    We have already used the new D2 and visible lamps to check. However, the errors are still there.
    Could I ask if there is a possibility of this error relating to a fault of the NIR detector PbS?
    If possible, could you please give us suggestions or recommendations about this?

    Thank you very much for your help.

    Best regards,


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