29
3) calculate an average value of measured gamma radiation ambient background
DER (further
– gamma background) when there is no reference radiation source. To do it,
wait no less than 600 s from the moment the instrument was placed on the dosimetric
equipment and then take 5 DER measurement readings at 150 s interval (no less). Then
calculate average DER meaning of gamma background
b
H
.
, by formula (5.1). One
segment of analogue scale must be indicated.
5
1
.
.
5
1
i
bi
b
H
H
,
(5.1)
where
bi
H
.
– i-th meaning of gamma background DER measurement, Sv/h;
4) move the dosimeter on the dosimetric unit so that geometrical center of the
detector coincides with the reference point, where reference DER value is 3,0
μSv/h, and
expose the dosimeter to irradiation. At that two segments of analogue scale must be
indicated;
5) wait at least 100 s after exposure starts, then take 5 DER measurement readings
(at 60 s interval at least). Then calculate average DER value
j
H
.
by formula
5
1
.
.
5
1
i
ji
j
H
H
,
(5.2)
where
ji
H
.
– i-th dosimeter reading when measuring DER in j-th tested point;
6) repeat measurements for points where reference DER value is 80,0; 800
μSv/h.
At that three segments of analogue scale must be indicated if DER is 80,0
μSv/h and four
segments if DER is 800
μSv/h;
7) move the dosimeter on the dosimetric unit so that geometrical center of the
detector coincides with the reference point, where reference DER value is 8,0 mSv/h;
8) expose the dosimeter to irradiation, at that five segments of analogue scale must
be indicated;
9) wait at least 60 s after exposure start, then take 5 DER measurement readings
(at 20 s interval at least) and then calculate average DER value by
j
H
.
by formula (5.2);
10) repeat the measurement for the reference point where reference DER value is
80 mSv/h. At that six segments of analogue scale must be indicated;
Phantom
Irradiation direction
Detector geometrical center
Figure 5.1
– The way for dosimeter with phantom be placed on the verification
dosimetric unit
Содержание PM1621
Страница 1: ...X RAY AND GAMMA RADIATION PERSONAL DOSIMETERS 1621 Models 1621 1621 1621 1621 OPERATING MANUAL...
Страница 13: ...13 Figure 1 2 General overview of the dosimeter...
Страница 14: ...14 Figure 1 3 Demounting the clip from 1621 and 1621...
Страница 21: ...21 Figure 2 2 Select the 1621 1621 dosimeter operating indication mode...
Страница 22: ...22 Figure 2 3 Setting the DE threshold values...
Страница 23: ...23 Figure 2 4 Setting the DER threshold values...
Страница 24: ...24 Figure 2 5 Indication of audio alarm state on off adjustment of sound volume of 1621 1621 dosimeter...
Страница 35: ...35 ATTACHMENT C reference OVERALL DIMENSIONS EFFECTIVE CENTER OF THE DOSIMETER DETECTOR Figure C 1...
