Phototransistor Based Position Sensitive Detector for Signal Detection in Photothermal Spectroscopy

Kusminarto Kusminarto ( Department of Physics, Gadjah Mada University)
Susilo Susilo ( Department of Physics, Semarang State University (UNNES))

Jurnal Matematika & Sains
Vol 9, No 2 (2004)

In a photothermal spectroscopy the signal change is indicated by the displacement of the probe laser beam, therefore a position sensitive detector (PSD) is required to record this displacement that is proportional to the intensity of the signal.A phototransistor (BPY62D) based PSD has been designed and constructed. A Darlington circuit has been employed to increase the sensitivity of the PSD. Sensitivity of 100.6 mV/mm has been achieved which covered a linear area of 0,5 mm.