Acquiring Lifetime Decays in EasyTau 2 with the FT250
Software Tutorial
Safety Issues
Summary
This tutorial shows step-by-step, how to acquire a lifetime decay with a FT250, using the EasyTau Wizard in EasyTau 2.
It explains the usage of the EasyTau 2 Software using version 2.0.
Preparation
Make sure that the correct laser (e.g. LDH-P-C-375B) is in place and connected to the laser driver (e.g. PDL 820).
Put the sample cuvette in the sample chamber (here, a solution of anthracene in ethanol will be used).
Turn on the laser driver and unlock the laser.
Switch on the FluoTime 250.
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’)

Easy Tau 2 window after creating a workspace, with the FT250 switched on

Polarizer set to Magic Angle indicated by the “M”
PLATZHALTER: FOTO ODER ZEICHNUNG MIT RICHTIGER POSITION DES POLARISATORS

Graphical User Interface of the Decay Wizard
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 field for entering Sample name, solvent and additional information
Select the right excitation source (here an LDH-375 is chosen).
Select the right Emission-Filter (a CG400 Longpass-Filter in this example, this depends on the sample and filter configuration):
Note: For systems equipped with a monochromator the detection wavelength has to be chosen. ◦ In case that the emission spectrum of the sample is unknown, it is possible to perform a fast spectral scan to find the wavelength emitting with the highest intensity by clicking the ‘Peak search’ - Button. A fast scan is then performed and the wavelength with the highest intensity measured will be automatically chosen as detection wavelength.

Measurement parameters for systems equipped with monochromators
Go to the “Acquire Decay” page. The decay is automatically measured, until 10000 photons in the peak channel have been counted. If you want to choose a different stop condition, change it and restart the measurement.
Switch off the Laser by turning the key on the laser driver
open the lid of the sample chamber
Remove your sample and replace it with a scatter sample (e.g. a Ludox solution)
Place the lid again
Turn the laser back on by turning the key of the laser driver to “Laser Active”
Click on ‘Start optimization’
Again, the best parameters for the measurement are being found (for the IRF optimization, only the attenuation is changed, while the repetition rate is kept the same as for the fluorescence decay measurement).
Click the ‘Acquire IRF’ - Button and thereby switch to the “Acquire IRF”-page.
The IRF is automatically measured, until 10000 photons in the peak channel have been counted.
The IRF is automatically measured and overlaid with the decay:
Fit a Lifetime Decay with EasyTau 2
Click the ‘Fit’ - Button below the parameter chart
The calculated parameters (e.g. lifetime τ) will be shown in the parameter chart
The calculated fitting function will be shown as a black graph
Also the residuals are shown below the decay graph
Generating a Report
The report window opens. Concerning the report, there are 3 presets to choose from: “Brief”, “Custom” and “Complete”. The “Brief” Report e.g. does not contain the Fitting function. In the “Custom”-Report, you can decide, which elements can be seen. The Report contains a table with the fitting values, the decay+fit graph and outputs of other performed analysis.
It is possible to print or save the report by clicking the according button in the top left corner of the window. While “Print” allows for creating a pdf-document

, if a pdf-prtiner is installed on the PC; the “Save” button

stores the report in a html-format.