FPC-TDC Spectrofluorometer is a first photon counting system, ideal for detecting extremely low fluorescence signals. It is optimized for samples with low fluorescence yield, ensuring high sensitivity and time resolution.
Description
FPC-TDC Spectrofluorometer
The FPC-TDC Spectrofluorometer is designed to study fluorescence decay in dim samples, where emitted light is extremely weak. Since fluorescence occurs on the nanosecond timescale (~10⁻⁸ s), the system uses a picosecond laser pulse to excite the sample and measures the time-of-flight of single photons emitted after deexcitation. Each detected photon passes through a monochromator and is captured by a photomultiplier, with the resulting photon arrival times reconstructing the full fluorescence decay profile.
To ensure accurate operation, the system maintains a low detection probability (<10% per pulse), making it exceptionally effective for samples with low fluorescence yield. The instrument is also adapted for electrochemical sample studies.
⬛ Quantities measured by the instrument include:
– Fluorescence time decay as a function of wavelength and, in the case of electrochemical samples, polarization potential,
– Emissive fluorescence spectrum,
– I-V characteristics,
– Open Circuit Potential (OCP),
– Current flowing through the sample.
Spectrofluorometer modules
⬛ The system consists of:
- Sample Chamber
- Picosecond Laser
- Monochromator for UV, VIS and IR range
- Photomultiplier
- Potentiostat
- Electrochemical Cuvette with platinum electrode and reference Ag/AgCl electrode
- Time to Digital Converter
Sample Chamber Interior
⬛ Optical path of laser beam and fluorescence light from the sample
Specification
⬛ Picosecond Laser
- Wavelengths: 405 nm, 450-460 nm, 630-640 nm
- Half width of the pulse duration: 150 ÷ 200 ps
- Maximum pulse repetition frequency: 1 MHz
- Light power of a pulse: 60 mW
- Trigger type: TTL up to 1 MHz
- Power supply: 12 VDC
⬛ Monochromator
- Spectral range: 200 ÷ 1200 nm
- Motorized slits, controlled via software
- Entrance and output slit opening range: 0 ÷ 5 mm
- Motorized internal shutter that provides full cut off of the light beam, controlled via software
⬛ Photomultiplier
R4998 Hammamatsu
- Anode to Cathode voltage range: up to 2500 V
- Spectral range: 300 ÷ 650 nm
- Transit time spread (FWHM): 160 ps
- Rise time: 0.7 ns
⬛ Time to Digital Converter
- Time resolution: 27 ps
- Maximum Measurement time: 500 ns
- Additional Reference channel for laser jitter minimalization
- Maximum impulse rate:
- 500 kHz for 2 channels measurement: sample and reference
- 1 MHz for 1 channel measurement
- Internal trigger frequency: 1 kHz ÷ 1 MHz
- External trigger mode, TTL input
⬛ Potentiostat
- Bias potential range: -5 V ÷ 5 V
- Current ranges: 10 nA, 100 nA, 1 µA, 10 µA, 100 µA, 1 mA, 10 mA
- Current resolution: from 1 pA to 100 nA (range dependent)
⬛ Controller
- Connection with PC: via USB 2.0
- RS485 socket to control devices
