Polimaster PM1701M User Manual

19
6.6 Calibration procedure
6.6.1 During the external examination check the instrument against the
following requirements:
- the instrument delivery kit shall comply with the operating manual;
- the instrument must be marked with clear inscriptions;
- the instrument must be free from pollution and mechanical damages that may
affect operation of the instrument.
6.6.2 During check-up it is necessary to check operation of the instrument as
described in the operating manual.
6.6.3 Metrological performance characterization
Check the relative error δ of mean count rate measurement
c
N
, s
-1
(pulses per
second) as follows:
1) switch on the instrument. Let it switch into search mode and wait at least
60 s. Then take 5 background readings N
bi
, s
-1
, and calculate
b
N
, s
-1
by formula
∑
=
=
5
1
5
1
i
bib
NN
(6.1)
2) place the instrument on the dosimetric calibration assembly with
137
Cs
gamma source so that the direction of calibration (Figure 1) coincides with the
radiation flow axis; and measured DER H
oj
in detection unit geometric center
(marked with “+” sign on the Figure 1) is 8.0 μSv/h. Irradiate the instrument.
3) wait at least 60 s after the irradiation start and then take 5 count rate
readings N
ci
, s
-1
; and then calculate average value of count rate by formula
∑
=
=
5
1
5
1
i
ci
c
NN
(6.2)
4) calculate average count rate
N
(without taking background) by formula
bc
NNN −=
(6.3)
5) calculate main relative measurement error δ of average count rate by
formula
%100⋅
−
=
N
NN
δ
, (6.4)
where N – calculated value of count rate – calculate by formula
oj
HN 155=
, (6.5)
where H
oj
– used DER value (μSv/h)

Polimaster PM1701M Specifications

General

Brand	Polimaster
Model	PM1701M
Category	Measuring Instruments
Language	English