Chapter 6 ā Maintenance, Transportation and Storage, Warranty and Service
Section 6.6 ā Illuminator Calibration and Preventive Maintenance
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Section 6.6 Illuminator Calibration and Preventive
Maintenance
Calibration and Verification
The INT100 INTERCEPT illuminator is calibrated and verified at the time of
illuminator manufacture, at the time of installation at the customer site, and at
six-month intervals thereafter. Qualified service personnel perform calibration
and verification activities.
Calibration and verification are performed using an external radiometer (ER) that
was specifically designed for use with the INTERCEPT illuminator. Each ER is
indirectly calibrated against an NIST traceable standard at six-month intervals.
The ER has the same dimensions as an illumination container, and is placed in the
same location within the tray as an illumination container.
The ER contains eight (8) photodiodes with UVA filters on both top and bottom
surfaces, that are dispersed over the surface such that the external radiometers
sample the same light field seen by the illumination container. During use, the
external radiometer is placed in each illumination tray and connected by a
cable to the computer of the INTERCEPT illuminator.
During the calibration process, the ER collects energy readings from the
INTERCEPT illuminator UVA bulbs at 3.0, 4.0, 5.0, 6.0, and 7.0 J/cm
2
. The instrument
software uses these energy readings to recalculate the calibration constants of
the photodiode sensors inside the illuminator. Calibration is followed by
verification, in which a different ER is placed in the illumination tray and
connected to the illuminator. As with the calibration procedure, energy readings
are collected from the radiometer at 1 J/cm
2
increments from
3.0 to 7.0 J/cm
2
. If
the energy readings seen by the illuminator using the new calibration constants
at each of the above dose points are within 10% of the energy readings seen by
the verification radiometer, then the new calibration constants become
permanent until the next calibration procedure.
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