Instruction Manual MIC type EC-912
Revision no.4
7 / 38
The smoke measuring equipment can also be used in other applications, where
measurements of smoke density are needed.
Specifications
System specifications
Measuring accuracy:
The overall measuring accuracy of the whole system is limited by the
measuring accuracy of the MIC, which is better than ±4% of full scale
reading (X = 1) for 0
X < 0.9.
Mains supply:
115 to 230 Vrms, 50 to 60 Hz without switch-over. Power consumption
max. 120 W independent of the applied voltage. Mains supply for vacuum
pump,
see Section 1.4.5
.
Cabinet:
19 inch desktop/subrack cabinet with power supply for MIC.
The control cabinet and the vacuum pump are intended for operation in normal laboratory
environment. However, the measuring ionization chamber may be applied in the temperature range 0-
100°C.
Measuring Ionization Chamber (MIC) type EC-912-10
General:
The MIC is designed to fulfil the specification in EN54-7 and EN14604.
See Ref. [5][6]
.
Radioactive source:
Isotope:
Am 241
Activity:
129.5 kBq (3.5 µCi) ±5%
Average
-energy:
4.5 M eV ±5%
Mechanical construction:
Americium oxide embedded in gold between two layers of gold. Covered
with a hard gold alloy. The source is in the form of a circular disc ø = 27
mm, which is mounted in a holder in such a way that no open cut edges
are accessible.
Ionization chamber:
Chamber quiescent current: I
CHO
= 100 pA
Chamber impedance:
R
CHO
= 1.9
•
10
11
±5%
The characteristics are measured in aerosol free air at:
Air pressure:
p =1.013
•
10
5
Pa (760 mm Hg)
Air temperature:
t = 25°C
Rel. humidity:
h = 48%