Limits...
Sources of Error in UV Radiation Measurements

View Article: PubMed Central - PubMed

ABSTRACT

Increasing commercial, scientific, and technical applications involving ultraviolet (UV) radiation have led to the demand for improved understanding of the performance of instrumentation used to measure this radiation. There has been an effort by manufacturers of UV measuring devices (meters) to produce simple, optically filtered sensor systems to accomplish the varied measurement needs. We address common sources of measurement errors using these meters. The uncertainty in the calibration of the instrument depends on the response of the UV meter to the spectrum of the sources used and its similarity to the spectrum of the quantity to be measured. In addition, large errors can occur due to out-of-band, non-linear, and non-ideal geometric or spatial response of the UV meters. Finally, in many applications, how well the response of the UV meter approximates the presumed action spectrum needs to be understood for optimal use of the meters.

No MeSH data available.


Spectral responsivity of two UV irradiance meters. Uncertainties for these data are given in Ref. [4].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4862826&req=5

f3-j64lar: Spectral responsivity of two UV irradiance meters. Uncertainties for these data are given in Ref. [4].

Mentions: Figure 3 shows the spectral responsivity, determined in monochromatic radiation, of two broadband UV meters used in semiconductor photolithography to determine the total exposure of a photoresist to 365 nm radiation from a filtered mercury source [4]. These meters have a maximum responsivity in the 365 nm region, and the responsivity then decreases to a much smaller, though non-zero, value at longer wavelengths. The instruments demonstrate differing amounts of increased responsivity in the near infrared (IR), with Meter A showing responsivity 2 to 3 orders of magnitude larger than Meter B in the 700 nm to 1000 nm spectral region. The increased IR responsivity is due to increased transmission in the IR by the glass filters, and because silicon photodiodes have their peak response in the near IR. The increased responsivity observed at wavelengths shorter than 300 nm is caused by fluorescence of the diffuser, which then re-emits longer wavelength radiation that passes through the filter to the photodiode. This was verified in Meter A by placing the diffuser between the filter and the photodiode. This effectively eliminated the responsivity near 275 nm.


Sources of Error in UV Radiation Measurements
Spectral responsivity of two UV irradiance meters. Uncertainties for these data are given in Ref. [4].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862826&req=5

f3-j64lar: Spectral responsivity of two UV irradiance meters. Uncertainties for these data are given in Ref. [4].
Mentions: Figure 3 shows the spectral responsivity, determined in monochromatic radiation, of two broadband UV meters used in semiconductor photolithography to determine the total exposure of a photoresist to 365 nm radiation from a filtered mercury source [4]. These meters have a maximum responsivity in the 365 nm region, and the responsivity then decreases to a much smaller, though non-zero, value at longer wavelengths. The instruments demonstrate differing amounts of increased responsivity in the near infrared (IR), with Meter A showing responsivity 2 to 3 orders of magnitude larger than Meter B in the 700 nm to 1000 nm spectral region. The increased IR responsivity is due to increased transmission in the IR by the glass filters, and because silicon photodiodes have their peak response in the near IR. The increased responsivity observed at wavelengths shorter than 300 nm is caused by fluorescence of the diffuser, which then re-emits longer wavelength radiation that passes through the filter to the photodiode. This was verified in Meter A by placing the diffuser between the filter and the photodiode. This effectively eliminated the responsivity near 275 nm.

View Article: PubMed Central - PubMed

ABSTRACT

Increasing commercial, scientific, and technical applications involving ultraviolet (UV) radiation have led to the demand for improved understanding of the performance of instrumentation used to measure this radiation. There has been an effort by manufacturers of UV measuring devices (meters) to produce simple, optically filtered sensor systems to accomplish the varied measurement needs. We address common sources of measurement errors using these meters. The uncertainty in the calibration of the instrument depends on the response of the UV meter to the spectrum of the sources used and its similarity to the spectrum of the quantity to be measured. In addition, large errors can occur due to out-of-band, non-linear, and non-ideal geometric or spatial response of the UV meters. Finally, in many applications, how well the response of the UV meter approximates the presumed action spectrum needs to be understood for optimal use of the meters.

No MeSH data available.