F. Garciapichel, A SCALAR IRRADIANCE FIBEROPTIC MICROPROBE FOR THE MEASUREMENT OF ULTRAVIOLET-RADIATION AT HIGH-SPATIAL-RESOLUTION, Photochemistry and photobiology, 61(3), 1995, pp. 248-254
The construction of a new type of microprobe for the measurement of sc
alar irradiance (integral dose rate) in the UV down to wavelengths of
250 nm is described. The microprobes were made from tapered standard o
ptical fibers and a tip-diffuser of magnesia/silica vitroceramic. The
sensing tips were ca 100 mu m in diameter and had maximal deviations i
n the angular response of +/- 15%. I present measurements of scalar ir
radiance at high spatial resolution within dry beach sand and suspensi
ons of microorganisms. These two media are environments in which micro
organisms are exposed to UV, either under natural (sand) or laboratory
conditions (suspensions). In both cases, the space distribution of UV
scalar irradiance, and thus the distribution of integral dose rates,
departed significantly from that predicted by absorptive effects alone
. The results underscore the importance of small-scale, in situ measur
ements of scalar irradiance for UV dosimetry in such scattering media.