Acquiring Emission Spectra in EasyTau 2 with the FT250
Software Tutorial
Laser Safety Issues
 | Your FluoTime 250 is a system of laser class 3. Make sure to comply with laser safety regulations. More information can be found here: laser_safety_issues |
Summary
This tutorial shows step-by-step, how to acquire emission spectra with an FT250 (equiped with a monochromator) using the Emission Spectrum Wizard in EasyTau 2.
Preparation
Switch on the FluoTime 250.
Put the sample cuvette (here, a solution of Anthracen dissolved in Ethanol) in the sample chamber.
Make sure that the correct laser (here: LDH-P-C-375) is in place and connected to the laser driver (here: PDL 820).
Turn on the laser driver and unlock the laser.
Start the EasyTau 2 software and wait until the status on the bottom right switches from yellow to green:
Load a workspace or create a new one by clicking “File“ → „New Workspace“.
After loading or creating a new workspace, the name of the workspace is displayed in the top line of the window (here, the workspace is called „Demo“).
Enter information about the sample and the solvent in the “Sample”-Tab (in this example: Anthracene solved in Ethanol).
Additional information about the measurement or the sample may be stored in the “Comment”-Field:
The system will perform a quick measurement of the emission spectrum and change the attenuator settings for an optimal signal countrate across the chosen wavelength range.
Once the optimization has finished the “Start Optimization” - Button the count rate displayed in the bar above the optimization-button.
NOTE: On the right side Easytau 2 shows a graphical preview of the emission spectrum. If you want to change the scanning range, you can go back to the “Sample Setup” - Tab by clicking the “Sample Setup” - Button. There, change the measurement parameters as desired and restart the optimization process. You'll have to re-do the optimization if you do this, before you can proceed to the “Acuire Spectrum”-page.
If your signal is relatively low in comparison to the dark counts of the system, a “blank”, i.e. an measurement of the buffer only can be acquired in order to properly subtract the background. This is mainly important with detectors with higher dar count rates, e.g. IR-PMTs. If you don't want to acquire a blank, directly step to the “Save & Exit”-page. To measure a blank, click on the “Acquire Blank” - Button.
Turn off the laser by turning the key of the laser driver from the “Laser Active” position to the “Locked” position.
Exchange the Sample in the chamber with the blank sample (here spectral grade Ethanol).
Close the lid and turn on the laser by turning the key of the laser driver from the “Locked” position to the “Laser Active” position.
Click the “Start” - Button to start the acquisition of the blank emission spectrum.
The grey graph overlaying the spectrum shows the normalized spectrum of the blank sample.
There is also a red graph which is not normalized. In this example the photons counted are so low that this graph can not be displayed.
When the acquisition is finished click the “Save & Exit” - Button.
Plotting the Stored Data
crv[0] is the raw data acquired for the Blank sample
crv[1] is the raw data curve
crv[2] is the spectral correction curve for your specific system
To display the different curves, the display settings for the graph have to be changed first (the measured count rate of the emission spectrum of the Blank sample in our example was so low that it will not be shown with standard settings).
The display settings for the graph are shown on the top right site of the graph window:
Click on the checkbox Y-Axis “Min” to activate the manual control of the display settings for this parameter.
Enter ”-0.01” in the text field behind the checkbox. This lowers the minimum y-value of the shown graph for which data points will be displayed.
On the right side of the “Plot” - Window you can find all the curves included in the data set under “Raw Data”.