Boron-Lined Proportional Counters0 pages
S Detection of thermal neutrons in pulse
nnnnmode
nnnnS Watertight HN connector
nnnnS High safety of use
nnnnSensitivity to thermal neutrons: Pulse mode 1 Background noise 2 | 4 <0.1 | c.s"1/ n.cm"2.s"1 c.s-1 |
Neutron flux range: Pulse mode 3 | 0.3-3x105 | n.cm"2.s"1 |
Exposure limits: Thermal neutrons Gamma exposure Gamma dose rate | max 1.7x1017 max 3.2x107 max 10 | n.cm"2 Gy.h"1 |
Insulating resistance at 800V 5: | min 1012 | Q |
Operating voltage: Nominal up to 200°C Maximum at 20°C Limit with no radiation | 800 850 950 | V V V |
Charge collection time 6: | 250 | ns |
Detector: Materials: Cathode Central anode Insulator Brazing | High purity aluminium 025um stainless steel wire Al203 NiAu and AgCu | |
Sensitive layer: B enriched in 10B Mass | >92% 0.2 | mg.cm"2 |
Filling gas (pressure) | Argon + 15% C02 (at 26.6 kPa) | |
Dimensions: Nominal diameter Detector length 8 Sensitive length | 25.4 394 278 | mm mm mm |
Connector: Type Insulator | Al, female HN Watertight Al203 |
This characteristic depends on the electronic equipment
nnnnassociated to the detector and the conditions of measurement.
nnnnThe figures have been determined with a Merlin-Gerin type SAITB
nnnnequipment, working in current amplification (G = 80 dB) with a
nnnndiscrimination threshold of 600 mV.
nnnnCharacteristic depending on the electronic equipment associated
nnnnto the counter.
nnnnValue depending on the associated electronic equipment and the
nnnnacceptable counting losses.
nnnnStandard counting measurement conditions. Under radiation,
nnnngamma rays generate low amplitude pulses which are not counted
nnnndue to the discrimination threshold. For dose rate more than 10
nnnnGy.h"1, pulse overlapping occurs which increases the counting rate
nnnnwithout correlation with the neutron flux.
nnnnThe insulating resistance is measured between anode and
nnnncathode at 800 V, with polarity (+) on the anode. CAUTION: a
nnnnwrong polarity could destroy the anode.
nnnnDisappearing of C02 induces an increase of the charge collection
nnnntime up to 2 us.
nnnnThe use of high purity aluminium further reduces the material
nnnnactivation after exposition to neutrons.
nnnnOn request this type of counter can be supplied with an integrated
nnnncable (CPNB24).
nnnnIncluding temperature increase due to gamma radiation (effective
nnnnabove 10 gy.h"1). The leakage current in the connection cable
nnnnincreases rapidly with temperature. It is therefore necessary to
nnnntake into account this characteristic, which limits the maximum
nnnntemperature so that the ratio of wanted signal/parasitic signal
nnnnremains acceptable. Consider CPNB24 detector if integral cable
nnnnneeded.
nnnn1 Vibration test conditions : frequency 60 Hz , amplitude ± 1 mm.
nnnnPHOTOIMIS
nnnn25/02/2008
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