Quantum sensor and units issue

• triscuit
In summary, the conversation discusses the use of quantum sensors in a wireless sensor network for a greenhouse and the issue of converting from watts per square meter to micromoles per square meter per second. The conversion formula for energy of a mole of photons is also mentioned.
triscuit
"quantum sensor" and units issue

I'm working on an wireless sensor network for a commercial greenhouse concerned with energy use and efficiency. Much of the literature regarding photosynthetic active radiation uses watts/square meter, but the client has requested a measurement in micromoles/square meter/second as the photon flux density. The commercially available "quantum sensors" use this unit, but we would like to use an array of simple photodiodes as a cost effective alternative.

So, how do you convert from W/m2 to umol/m2/s? We will specifically be looking at and distinguishing between wavelengths 400-500 and 600-700 (because that's what the plants need). If we use a passive sensor with a voltage output, how do I translate that into moles of photons??

haha, that's funny, I never heard the expression "a mole of photons" before

Now, the conversion is very simple:

if v is the frequency of the light (in Hz), then the energy of a mole of photons is given by:

E = h x Na x v

where h is Planck's constant and Na is Avogadro's constant.

A mole of photons per second is then the above expression in Watts.

I understand your concerns about the use of different units in the literature and the client's request. However, the conversion from watts per square meter to micromoles per square meter per second is not a straightforward one as it depends on the spectral distribution of the light being measured. In order to accurately convert between these units, you will need to use a spectroradiometer to measure the spectral distribution of the light and then use a conversion factor specific to that spectrum.

As for using photodiodes instead of commercially available quantum sensors, it is possible to use them as long as you have a way to calibrate the output voltage to the desired units of micromoles per square meter per second. This calibration will also depend on the spectral distribution of the light being measured.

In terms of distinguishing between wavelengths 400-500 and 600-700, you will need to use filters or spectrally selective photodiodes to measure the specific wavelength ranges.

In summary, the conversion from watts per square meter to micromoles per square meter per second is not a simple one and will require a spectroradiometer for accurate measurements. Additionally, using photodiodes as a cost-effective alternative will require proper calibration and possibly the use of filters or spectrally selective photodiodes to measure specific wavelength ranges.

1. What is a quantum sensor?

A quantum sensor is a device that uses the principles of quantum mechanics to detect and measure physical quantities such as light, magnetic fields, and temperature. It operates by detecting and manipulating the quantum states of particles, such as photons or electrons, to make highly precise measurements with minimal disturbance to the system being observed.

2. How does a quantum sensor work?

A quantum sensor works by using quantum phenomena, such as superposition and entanglement, to measure the properties of a system. It typically consists of a probe, which interacts with the system being measured, and a readout, which detects and interprets the resulting changes in the probe's quantum state. The sensitivity and accuracy of a quantum sensor are determined by the properties of the probe and the readout, as well as the environment in which it is being used.

3. What are some common types of quantum sensors?

Some common types of quantum sensors include quantum magnetometers, which measure magnetic fields; quantum thermometers, which measure temperature; and quantum photodetectors, which detect and measure light. Other types include quantum gyroscopes, accelerometers, and gravimeters, which measure rotation, acceleration, and gravity, respectively.

4. What are the units used to measure quantum phenomena?

The units used to measure quantum phenomena vary depending on the specific quantity being measured. For example, the unit for measuring light is typically the photon, while the unit for measuring magnetic fields is the tesla. Other units used for quantum measurements include the kelvin for temperature, the hertz for frequency, and the electron volt for energy.

5. What are some potential applications of quantum sensors?

Quantum sensors have a wide range of potential applications in fields such as medicine, navigation, and communications. They can be used for non-invasive medical imaging, precise navigation in GPS-denied environments, and secure communication through quantum encryption. They also have potential uses in detecting and monitoring environmental pollutants, improving the accuracy of timekeeping, and advancing our understanding of fundamental physics.