EPSA-RINKO is an autonomously deployable data logger for long-term DO measurements. In order to protect the sensing foil against accumulating bio-fouling, the instrument has a mechanical wiper to sweep the optical window. The sensor is coated with photostimulable phosphor (PSP) on the outside of the pressure-resistant acrylic optical window, measuring the phase difference between phosphorescent time lengths. The excitation blue LED pulse generates a red phosphorescence pulse, which in turn has an inverse correlation with the oxygen partial pressure in the water (DO concentration). Phosphorescent time lengths under oxygen-free conditions are long. However, under high DO concentration conditions, the time length shortens. Since the method does not consume oxygen, there is no need for stirring.
| Parameter | Temperature | DO |
| Range | -3~45℃ | Air saturation: 0~200% |
| Accuracy | ±0.02℃(3 to 31 ℃) | Non-linearity ±2 % FS |
| Resolution | 0.001 ℃ | 0.01 %* |
