Measurement Parameters - Fluke Biomedical RAYSAFE 452 Manual Del Usuario

The instrument counts discharge avalanches in the Geiger-Müller
pancake, caused by alpha, beta and gamma radiation. After each
discharge, the pancake takes some tens of microseconds to recharge,
called the dead time. The instrument corrects for the effect of this
dead time each millisecond, automatically.
The instrument has no zero adjust functionality, and measurements
include background radiation.

Measurement parameters

Counts
Counts is the sum of all discharge events during the current
measurement, corrected for dead time every millisecond.
Count rate
Count rate uses an algorithm that detects changes in radiation with a
response time of a few seconds or less, but may in some cases need
more time to stabilize. See Table 3 on page 11.
Count rate is averaged over 1 second or longer, and updated once per
second, why the instrument needs a stable radiation level for at least
2 seconds to reliably measure the rate.
RaySafe 452 – Users Manual (EN)
RATE
(cps)
≤ 0.5
1.5
5
15
50
150
500
≥ 1500
Table 3. Count rate stabilization times.
Peak count rate
Peak count rate is the highest displayed count rate since last reset.
See definition of count rate.
11
TIME TO MAX
RATE
(cpm) STABILITY
≤ 30 60 s
90 33 s
300 10 s
900 10 s
3 k 10 s
9 k 7 s
30 k 4 s
≥ 90 k 2 s