Fission Chambers for Out-of-Core Use CFUM 110 pages

Product specification
CFUM11
Neutron detector
Out-core fission chamber
Application
Features
Detection of thermal neutrons in a flux
range of 10 to 1011 n.cm-2.s-1
High safety of use
Integral HN connector
Nuclear characteristics at 20°C
Sensitivity to thermal neutrons 1: Pulse mode
Fluctuation mode
Current mode
10-1
4x10-27
-14
10
Gamma sensitivity:
Exposure limits:
Gamma radiation:
Thermal neutrons
Exposure
Dose rate
5
10 - 107
105 - 3x1010
7
11
10 - 10
n.cm-2.s-1
n.cm-2.s-1
-2 -1
n.cm .s
10-9
Pulse mode 2
Fluctuation mode 3
4
Current mode
Neutron flux range :
c.s-1/n.cm-2.s-1
A2.Hz-1/n.cm-2.s-1
-2 -1
A/n.cm .s
A/Gy. h-1
19
-2
max 2x10
max 109
max 104
n.cm
Gy
Gy.h-1
Notes.
Electrical characteristics
6
12
Insulating resistance at 600V :
Operating voltage:
min 10
7
Charge collection time :
Detector:
Capacitance
600
800
1300
V
V
V
50
Nominal up to 250°C
Maximum at 20°C
Limit with no radiation
Ω
ns
70
pF
Unless otherwise stated, all characteristics are given at 20°C
1
Values depending on the characteristics and the calibration of the
measurement equipment. The pulse sensitivity is calculated from
the (α−neutron) discrimination curve for a discriminating threshold
corresponding to a counting rate of 0.01 c.s-1.
2
Pulse mode operating range for a measurement equipment with a
resolution shorter than the collection time of the detector.
3
Fluctuation operating range measured on an equipment with a 1 to
30 kHz band pass.
4
Current mode operating range: the lower limit of the current mode
operating range depends on the electronics (especially on the
input amplifier) and on the signal / parasitic current ratio (parasitic
current = leakage current + gamma current + α-current). The
upper limit is depending both on the detector and electronics (loss
of linearity).
5
Flux corresponding to a 1 % sensitivity loss of the detector.
6
For sensible fission chambers (s > 0.1 c.s-1/n.cm-2.s-1), the αcurrent is predominant in relation to the leakage current from the
insulators. The insulating resistance is then measured by the ratio
∆U/∆I of the I=f(U) curve determined without any ionizing radiation.
7
Charge collection time: the measured value depends on the
electronics and on the cable capacitance.
8
The use of a gas mixture (Ar + N2) increases the electron velocity
and therefore favours a short collection time.
9
In order to avoid humidity penetration during storage, the
connector is closed with a cap to be removed just before use. As a
general rule, prevent any humidity penetration at the connection
level (refer to "Instructions for use and handling" in the package).
Other connector types are possible . To be required when
ordering.
10
Including temperature increase due to gamma radiation (effective
above 104 Gy.h-1). The maximum operating temperature is
indicated for pulse operating mode. The leakage current in the
cables increases rapidly with temperature. It is therefore
necessary to take into account this characteristic, which limits the
maximum temperature so that the ratio of wanted signal/parasitic
signal remains acceptable.
11
Vibration test conditions: frequency 60 Hz, amplitude ± 1.5 mm.
Mechanical and physical characteristics
Detector:
Materials:
Sensitive layer:
Filling gas 8 (pressure)
Dimensions: Nominal diameter
Detector length
Sensitive length
Connector: Type 9
Insulator
Case, electrodes
Insulator
Brazing
Uranium enriched in 235U
Mass
Aluminium
AI2O3
AgCu
>90%
0.7
mg.cm-2
Argon + 4% nitrogen
(at 400 kPa)
25.4
mm
227
mm
120
mm
Watertight
female HN
Al2O3
21/01/2008