Intermittent Radiation Sources; Measure Without Lid - Fluke Biomedical RAYSAFE 452 Mode D'emploi

the instrument typically detects a few muons per day, but
at higher altitudes, for example when travelling by air, the
number increases to hundreds per day.
Mean photon energy
Mean photon energy uses a moving average of up to 10 seconds.
The averaging time is shortened whenever a change in dose rate is
detected.

Intermittent radiation sources

Dose is accurate for short pulse lengths due to the fast dead time
corrections and sensor algorithms. See Figure 9 on page 10.
1000
100
10
1
0.1
0.001 0.01 0.1
Pulse length (ms)
Figure 9. Performance on intermittent radiation, for temperatures up to 30 °C
(86 °F). Green area: Response within ±20 % of the response at continuous
radiation.
RaySafe 452 – Users Manual (EN)
1 10 100
Dose rate is averaged over 1 second or longer, and updated once per
second. Therefore, the instrument needs a radiation pulse of at least
2 seconds to reliably measure the rate of the pulse. It is possible to
manually calculate the rate of a shorter pulse using the measured
dose and a known pulse length.
When measuring on continuously repeating pulses, for example from
pulsed fluoroscopy or linacs, the instrument measures average dose
rate. If the duty cycle is known, it can be used as a correction for
calculating the radiation rate in the pulses.
NOTE At temperatures above 30 °C (86 °F) the instrument's ability to
handle radiation from intermittent sources gradually declines
with increasing temperature.

MEASURE WITHOUT LID

When measuring without lid, for example on a potentially
contaminated surface:
1. Unmount the lid. When measuring without lid, the active sensor is
the Geiger-Müller pancake, G in Figure 1 on page 4.
2. Turn on the measurement sound.
Tip: Long press on the left arrow button toggles the measurement
sound on or off.
3. Hold the instrument close to, but not in contact with, the surface.
4. Scan the surface slowly, approximately 1 cm/s (½ inch per
second).
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