I am currently working on a project to develop a fibre optic dosimetry system. The system uses an organic scintillator (BCF-60), which emits green light at 530 nm and has an active volume of 0.8 mm³.
As part of the project, I am designing a transimpedance amplifier (TIA) circuit using the S1223-01 photodetector, which I selected based on its spectral response range (360 nm to 900 nm) and photosensitivity (0.1–0.6 A/W).
To simulate a clinical environment, I use a function generator to produce a 360 Hz pulse signal, which drives a 5 mm green LED. The light signal is transmitted through a 2-meter-long, 1 mm diameter fibre optic cable. The other end of the fibre is coupled to the photodiode, which is connected to the TIA circuit built around the OP07CP op-amp, using a feedback resistor of 1.1 MΩ. The output of the TIA is then connected to a second-stage amplifier (a voltage follower using the OP276) configured with unity gain.
However, I am currently experiencing noise in the output signal, and I plan to test the setup using a National Instruments DAQ (NI 6363) for further analysis.
I attached circuit diagram in which I am using TIA (OP07CP) I am getting noise of around 100 mV at output of TIA. kindly please guide me how I could reduce this noise.
Hasham
