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If you want to learn more about diseases, organ function research, or new drug development, you can use heavy oxygen water. Heavy-oxygen water is an isotope of water used in many different ways. In the past, chilled mirror dew point metres, wet and dry bulb hygrometers, and humidity-sensitive capacitors were the few methods to determine a high concentration of oxygen water vapour in the air. However, these could not differentiate between water vapour and heavy oxygen water vapour because they have the same physical and chemical properties.
Heavy oxygen water vapour is always mixed with water vapour when used. There are many sensors for measuring humidity, but a single sensor with good selectivity is a better choice than other sensors.
Types of Water
Heavy water with deuterium hydrogen atoms is not the only known water that differs from other types of water. Many kinds of water have a slightly different number of protons, neutrons, and electrons in their structure. Many kinds of water have a slightly different number of protons, neutrons, and electrons in their structure.
- Tritiated water: It is similar to deuterium water but with a different hydrogen isotope than deuterium water. Hydrogen is in its tritium form in tritiated water, which is tritiated water. Tritium is radioactive, so even the water molecule that comes from it is radioactive and corrosive.
- Semi-heavy water: Because of the name, you can tell this water is a mix of regular and heavy water. In this case, several water molecules have deuterium hydrogen atoms instead of protium hydrogen isotopes. This means that semi-heavy water is an excellent middle ground between light and heavy water.
- Water with heavy oxygen: They are called heavy-oxygen waters because they have isotopes of oxygen like O17 and O18 in their structure instead of the usual O16, which makes them more stable. Similar to tritiated water, heavy waters are also used in radioactive systems.
Experiments and Results
Detection of Water Vapour
The humidity sensor works in DAS-TDLAS mode to look for water vapour. Using a triangle signal, the diode laser scans across the line where the laser absorbs water vapour. The voltage signal that changes with the amount of power used is recorded. A commercial humidity sensor (Rotronic, HP32) is used to get the relative humidity of the gas that has been detected. This sensor has a precision of 0.5% RH.
The measured relative humidity of the water vapour samples is 1.95% RH, 2.60% RH, 3.25% RH, 3.90% RH, 4.55% RH, 5.20% RH, 5.85% RH, 6.50% RH, 18.26% RH, 58% RH, 76% RH, and 88% RH, respectively.
It is said that the signal profiles are all the same and that the absorption is more noticeable when there is a lot of moisture in the air. Linear fitting is done to the curves. In this example, the residual sum of squares is 19.59, and the coefficient of determination is R 2 = 0.993 13.
The rate at which water vapour can be detected is 9.64 mV/ per cent RH. It is found that the proposed sensor has satisfactory linearity and that the measuring accuracy for water vapour is within 0.5% RH.
Heavy Oxygen Water Vapour Detection
Using the WMS-TDLAS mode, we see how well the new humidity sensor works. When the current drives, it causes the central wavelength to travel across the absorption line. The driving current is changed simultaneously by a sine wave and a triangle signal.
Triangle: The frequency of the triangle signal is 100 Hz, and the frequency of the sine wave is 10 kHz. There is a good amount of modulation. There were different amounts of relative humidity when the second harmonic signals were measured.
The Rotronic HP32 humidity sensor detects water vapour and measures relative humidity. They have 3.4% RH, 6.8% RH, 10.2 % RH, 13.6% RH, and 17.9% RH, respectively. There are many similarities between the profiles. They reach their peaks at the centre of the lines absorbing the most energy.
How much is heavy oxygen water vapour related to light being sent in the WMS-TDLAS mode? There is a relationship between the peak of the second harmonic and the amount of relative humidity in a room. The residual sum of squares is 11.03, and R2 = 0.9850. There is 30.91 mV/per cent RH sensitivity for detecting heavy oxygen water vapour, which is how sensitive it is. The proposed sensor has satisfactory linearity, and the measuring precision for heavy oxygen water vapour detection is within 1.0% RH of what it should be for the sensor.
Conclusion
The same humidity sensor can detect water vapour and heavy oxygen. This paper discusses how to make this happen. TDLAS is an excellent way to tell the difference between isotopes. The light source is a single 1372 nm DFB diode laser with a wavelength range covering both absorption lines of water vapour and heavy-oxygen water vapour.
A Herriott gas cell with a 12 m optical length is used to improve SNR, making the optical length about 60 times longer. Detection of water vapour is done in the DAS-TDLAS mode, and the detection accuracy is within 0.5% RH. Heavy oxygen water vapour detection is done in the WMS-TDLAS mode, and the accuracy of detecting heavy-oxygen water vapour is within 1.0% RH.
