Time-resolved fluorescence

The time-resolved fluorimeter (Processo FAPESP Multiusuário 96/12492-8, e upgrades Projetos FAPESP 01/11721-3 e 09/16765-0) has separate excitation and detection systems.

The excitation system uses a Titanium-Saphire Tsunami 3950 laser to generate laser pulses within the 840 - 1000nm range with a maximum pulse repetition frequency of 4MHz. These pulses are selected (3980-25, Spectra Physics pulse selector) to operate in the range of 80 - 400KHz. The beam then passes through a third harmonic generator (GWN-23PL, Spectra Physics) so that the emerging beam has wavelengths between 280 - 330 nm and a total half-size width of 48ps.

The detection systems consists of: (1) Edinburgh Instruments FL900CDT spectrophotometer, (2) Hamamatsu R3809U photomultiplier for fluorescence emission detection, (3) multichannel analyzer (MCA) and time-amplitude converter (TCA) for temporal detection of fluorescence. Temperature can be controlled within the 5 - 90°C range and different optical paths (2 to 10mm) can be employed to measure samples with volumes of 300 µL to 3mL.