The instruments used to detect and measure light and color often have similar capabilities, all revolving around the measurement of electromagnetic radiation. They even have similar-sounding names such as radiometers, spectrometers, and spectroradiometers that do not give much away about their characteristics. However, their functions and applications can vary.
As a radiometry professional or a systems engineer, you must understand the differences between radiometers, spectrometers, and spectroradiometers so that you can apply them in the correct applications in a proper setup. In radiometry, these instruments are applied interchangeably although their measuring capabilities may be different.
As experts in manufacturing radiometry instruments, we believe it is best to use the most relevant tools for your applications so as to achieve accurate results and better efficiency. In most cases, such radiometry tools are used in tandem with other equipment such as optics and additional sensors to achieve the desired action or output.
Here’s a comparison of common radiometry tools and their specific capabilities in measuring light, display, and color.
What is the Difference Between Radiometers, Spectrometers, and Spectroradiometers?
The differences between radiometry tools can be identified by looking at the scope of each tool. For instance, the biggest distinguishing factor between radiometers, spectrometers, and spectroradiometers is the type and quality of their measurement. Other parameters include their operating principle, dependence on other tools, and resolution.
Radiometers can only detect and measure electromagnetic radiation within a particular wavelength range. Spectrometers offer slightly better coverage as they can detect and measure a wider spectrum with the ability to provide additional details such as amplitude. Spectroradiometers bring the advantages of radiometers and spectrometers together and cancel their disadvantages by being a portable, simple tool that can detect and measure a wide variety of light sources and provide additional information such as flux and chromaticity.
At first look, from an application point of view, it would make sense to invest in a spectroradiometer since it can cover a wide variety of applications. However, as a technician, you may be better off using any of the three tools if your main applications fall under any one of their gamuts. The detailed comparison below will help you make a better decision.
Note: There is another tool called spectrophotometers that has evolved from these spectroscopy tools. It is used to measure surface reflectance to understand the absorbance of the material being tested. It’s not usually compared with radiometers and spectrometers as it has more to do with objects and their materials than light sources.
Comparison: Radiometers vs Spectrometers vs Spectroradiometers
The major differences between radiometers, spectrometers, and spectroradiometers are:
Radiometers:
- Highly portable
- Uses a single sensor
- Can be used as a standalone measurement tool
- Quick measurements
- Quantitative measurements only
Spectrometers:
- Not portable
- Uses multiple sensors
- Requires additional tools to work
- Measurements take time due to post-processing
- Quantitative and qualitative measurements
Spectroradiometers:
- Highly portable
- Uses multiple sensors
- Can be used as a standalone measurement tool
- Moderately fast measurements
- Quantitative and qualitative measurements
What is a Radiometer?
A radiometer is an instrument that can measure a light source’s amount of electromagnetic energy within a specific wavelength range. Examples of such a range are ultraviolet (UV) and infrared (IR). For most applications, radiometers are used to measure energy beyond the visible light spectrum.
Radiometers measure energy in watts (W) by detecting the voltage or current of an incoming light source. In most cases, radiometers are calibrated for a particular range, making it the biggest difference when compared to spectrometers and other radiometry tools that are wavelength-independent.
Multi-Channel Radiometer by CI Systems
Applications of Radiometers
Also known as roentgenometers, radiometers are primarily used in fields such as electrical and mechanical engineering, construction, aeronautics, thermal imaging, and art conservation.
For example, IR radiometers are widely applied to detect heat maps of objects and persons. Such a system can be employed to detect the surface heat of a motor in an assembly line. Automated radiometers are also used in airports to scan luggage. Other types include microwave and UV radiometers.
Almost all radiometers available in the market today have evolved from two original types, namely the Crookes radiometer and the Nichols radiometer. Both use different measurement techniques and therefore require controlled environments. For example, a radiometer developed using Nichols’s principle will need a complete vacuum environment to work flawlessly. You should note that modern evolutionary tools do away with these requirements, making them usable in any circumstance.
Unique Features of Radiometers
- Provide quantitative measurements.
- Small in size, making them highly portable.
- Easy to set up and connect to a system.
- Fast measurement due to a single sensor and focus on a particular wavelength range.
Modern radiometers pack more punch than their older counterparts. For instance, the Solar Blind Imaging Radiometer (SBUV) by CI Systems is capable of covering a large area on any field to capture, detect, and measure solar radiation. Key application areas for such a tool include agriculture and telecommunications.
What is a Spectrometer?
Spectrometers can detect, measure, and analyze electromagnetic radiation across different wavelength ranges. They use multiple sensors and additional components to split incoming light energy to detect their wavelength spread, quality, energy, as well as color. Compared to radiometers, this additional ability to measure spectral components makes it a more sought-after tool in engineering and astronomy.
As you can see, the major difference between spectrometers and radiometers is that the former can provide a qualitative measurement. They can also define the wavelengths and scales of a source of light whereas a radiometer can only give an estimate. This makes spectrometers more advanced than radiometers.
Applications of Spectrometers
Naturally, spectrometers are used in applications that require accurate energy data and wavelength information. However, they need to be used with other tools to gain maximum advantage.
Applications include photometry, chemistry, food analysis, and in industrial quality control systems.
Unique Features of Spectrometers
- Provide qualitative and quantitative measurements (in watts per square meter)
- Must be connected with additional tools like optics, spectral cameras
- Have multiple sensors for accurate readings
What is a Spectroradiometer?
A spectroradiometer can be considered a combination of a spectrometer and a radiometer. Therefore, as the name suggests, it is capable of measuring the wavelengths, irradiance, flux, and energy of a light source. Spectroradiometers are the best of both tools mentioned above, making them highly analytical, accurate, and powerful.
Spectroradiometers can be used as a standalone tool to measure light intensity, even in rough conditions where using other electronic instruments may not be feasible. This is their biggest advantage. Modern spectroradiometers have far more advantages like Bluetooth and WLAN integration and remote sensing capabilities. A good example of an advanced spectroradiometer is the SR-5000N Spectroradiometer by CI Systems that has the ability to detect light sources that are kilometers away.
Notably, a spectroradiometer combines the advantages of radiometers and spectrometers. For instance, it can be used as a standalone device and can be carried to sites for reading (including in harsh conditions). That makes it a preferred instrument when compared to a radiometer or spectrometer.
The SR-5000N IR spectroradiometer by CI Systems
Applications of Spectroradiometers
The main applications of spectroradiometers include UV measurement, display measurement and calibration, and electric light fixture testing. They are preferred for their high-
precision measurements and standalone execution.
Unique Features of Spectroradiometers
- Provide detailed measurements of light energy, wavelengths, and amplitude
- Can work as a standalone light measurement instrument
- Highly portable
Conclusion
This comparison between radiometers versus spectrometers versus spectroradiometers shows the major and minor differences between the light measurement tools. We hope knowing these differences will help you make wiser decisions in your trade.
If you’re looking for further assistance on these tools and on buying the best option for your business, contact us for a brief chat. CI Systems manufactures a wide range of radiometers and spectroradiometers that we’re sure will complement your business in providing accurate and detailed light measurement readings.