UV meters and radiometers for irradiance and UV dose

UV meters and radiometers capture irradiance or UV dose within defined spectral ranges. A sound selection requires the radiation source, the wavelength range, the expected reading, the geometry and the operating environment to match. Opsytec offers portable radiometers, dosimeters and process-side measuring systems for UVA, UVB and UVC applications. The product overview leads to the right system by measuring task and measuring range.

How irradiance and dose are defined and which influences determine the measurement result is explained on the page measuring UV dose and irradiance correctly.

What a UV meter measures – and where the limit lies

A UV meter returns the irradiance within a fixed spectral band and, integrated over time, the UV dose. What governs the reading is the spectral responsivity of the sensor; design and measurement physics are covered under design and error sources of UV sensors.

Broadband radiometers integrate the radiation within that fixed responsivity and suit fast process and dose checks. Spectroradiometers resolve the radiation by wavelength and are needed whenever spectral distribution, peak position or spectral mismatch has to be assessed – that is what spectroradiometers for wavelength-resolved measurement are for. Which class fits which measuring task is settled by broadband or spectroradiometer: selection by measuring task.

The following overview leads from the requirement to the instrument; the model comparisons are given on the product pages.

For UVC sources – low-pressure lamps, UVC LEDs and excimer lamps – the page UVC meter compares instruments, sensors and measuring ranges.

For LEDs from the UV to the near infrared, the page LED measurement technology assigns spectrum, irradiance and luminous flux to the appropriate meters.

What the instruments report

• Irradiance – the instantaneous value in W/m², mW/cm² or µW/cm²; 10 mW/cm² equals 100 W/m². convert irradiance
• UV dose – irradiance multiplied by exposure time in J/m², the governing quantity in UV curing and UV disinfection. calculate UV dose
• Spectral range – UVA 315–400 nm, UVB 280–315 nm, UVC 200–280 nm; the boundaries are convention rather than physics, see spectral ranges and standards.

All sensors and instruments are calibrated and traceable to national standards; recalibration is carried out in our own laboratory accredited to DIN EN ISO/IEC 17025. Details are set out under UV calibration, the appropriate interval under calibration interval.

Which quantity do I need – irradiance or dose?
Irradiance (mW/cm² or W/m²) is the instantaneous value and the right quantity for setting up or monitoring a source. Dose (J/m² or mJ/cm²) is its time integral and the governing quantity in UV curing and UV disinfection, where the cumulative effect matters. Instruments such as tinyTracker and curelog capture the dose directly in the process.

Which spectral range does the instrument have to cover?
That of the source, not of the instrument. Because the sensors are interchangeable and individually calibrated, one display unit covers several ranges; if the spectrum is unknown or changing, broadband or spectroradiometer: selection by measuring task helps to find the appropriate instrument class.

How do I choose the measuring range?
By the irradiance expected at the measuring position, not by the maximum output of the source. The reading should sit safely inside the range – close to the upper limit there is a risk of overdriving, close to the lower limit the signal-to-noise ratio suffers.

Are the instruments calibrated and recalibratable?
Yes, all sensors and instruments ship calibrated and can be recalibrated. Procedure and scope are set out under UV calibration, the question of the appropriate interval under calibration interval.

Find the right sensor: The UV Sensor Finder proposes the three best-matching UV sensors and meters by application, wavelength and form factor – with key values, system partner and reasons.