The variance when measuring peak intensity (mW/cm2) lies in the sample rate of the radiometer versus the time spent under the focal point of the lamp (speed).
A focused UV lamp, has a 3/4 inch focal plane. The UV Power Puck® samples at 25 samples per second. Using the sample rate of the Power Puck, we find that at the 10m/min speed, it is able to accumulate 3.85 samples each inch, but only 2.88 samples which are under the focal plane.
For example:
| 10m/min |
=390 inches/minute
=6.5 inches/second |
| 25 samples/sec |
=25 samples/6.5 inches
=3.85 samples/inch |
| .75 inch in the focal plane |
=2.88 samples under the focal plane (3.85 X .75) |
Using the above math, here is what happens at 20m/min:
| 20m/min |
=780 inches/minutes
=13 inches/second |
Now 25 samples/second (capability of UV Power Puck) = 25 samples/13 inches
OR
| but |
=1.92 samples per inch
=only 1.44 samples under the focus (1.92 X .75) |
At some other speeds, here are the results:
30m/min = .96 samples under the focus
40m/min = .72 samples under the focus
50m/min = .58 samples under the focus
60m/min .= 48 samples under the focus
70m/min = .41 samples under the focus
