UV Flashcards
UVA wavelength
400-315 nm
UVB wavelength
315-280 nm
UVC wavelength
280-100 nm
Thermal Daily Limit
E = 10,000 J/m^2 over any 8 hour period
315-400 nm eye
Photochemical Daily Limit
E eff = 30 J/m^2 over any 8 hour period
weighted, 180-400 nm eye and skin
Typical spectral irradiances for UVA
4 mW/cm^2
Typical spectral irradiances for UVB
0.2 mW/cm^2
Uses of UV radiation
room lighting
curing resin
germicidal irradiation (UVC)
black light
Properties of vacuum thermopile detectors
bare detector
converts optical energy to heat enregy
broad range of wavelengths
flat response
Properties of photon detectors
photoelectric or solid state
use with diffuser or filter
restricted range of wavelengths
match detector to lamp type
non uniform spectral response
What is UV spectrometry used for?
Calibration
intergrated counts at each wavelength step
Range of UV in tissue
0.1 mm
Which wavelength range is most damaging?
UVC
(280 - 100 nm)
Which wavelength range is most effective at causing erythema?
UVB
(315 - 280 nm)
What are the bio-effects of UV exposure?
vitamin D production
erythema
cataracts
sunburn
skin cancer
What is the weighting factor S(λ)?
used to modify the spectral irradiance data to take into account the wavelength dependency of adverse health effects on both the eye and skin
applies for 180-400 nm
What is the S(λ) peak?
S(λ) = 1 at 270 nm
PPE used in phototherapy
eyewear
visors
What is MED?
Minimal erythema dose in an individual
What is SED?
Standard amount of erythemally weighted radiation 100J/m^2
What is effective irradiance?
Weighted spectral irradiance (W/m^2)
Who provides guidelines for QC of UV sources?
British Association of Dermatoligists
