Table of Contents
Advertisement
Aer 5400
15. 2. Changing the threshold level for the count rate
Configuration window of components CMP1 and CNT1
Two components, a voltage comparator (CMP1) and a counter input (CNT1) are used for gross count
rate measurements. The comparator output is internally connected to the counter input. A digital
pulse will appear at the counter input if the detector signal exceeds the threshold level of the
comparator. Because the height of the detector signal is related to the emission energy of the decay
event, the count rate contains only events above the energy corresponding with the threshold. This
allows the configuration of the counter either as gross alpha or total event counter. The threshold
level can be adjusted in the component window of CMP1, edit field "Threshold voltage". To count
alpha and beta decays, enter 100mV, for alphas only, enter 350mV.
The alert threshold for the count rate can be configured in the configuration window of component
CNT1 ("Alarm if count rate becomes higher than"). The alert is disabled in delivery state ("inactive"
selected from the list box "Alarm index higher than").
15. 3. Adjusting parameters for the gamma background compensation
Configuration window of component SPEC1
Instruments without dynamic gamma compensation
To enter the background count rate, the parameter "Fixed Background Count Rate" is available in the
table "Calibration constants". The unit is cpm (counts per minute).
Instruments with dynamic gamma compensation (double detector)
The parameter table contains in that case the item "Ratio Gamm Filter/Compensation" instead of the
"fixed background Count Rate". This parameter can be calculated according the chapter "Dynamic
gamma compensation".
15. 4. Changing units (US/SI) and dose coefficients
Configuration window of component SPEC1
The activity and dose results can be presented either in traditional US units or in international SI units,
depending on the selection in the list box "Unit scheme". Changing the unit scheme requires always
the changing of the dose coefficients. Dose coefficients must be stated in relation to the selected
dose unit. That means for US unit scheme, the unit of dose coefficients is DACh/(Bqh/m³). The dose
coefficient unit in case of SI unit scheme is µSv/(Bqh/m³). The values can be entered into the table
"Calibration constants". There, the parameters "Dose Coefficient Alpha", "Dose Coefficient Beta" and
"Dose coefficient Unat" are available.
The factory-set coefficients are adjusted with respect to the normative 10CRF20 of the US-DOE.
Because there are specific laws for various applications and countries, the user must change these
constants in accordance with the local regulations.
Coefficient for
Plutonium
Natural Uranium
Strontium
20
in DACh/(Bqh/m³)
10CRF20
10CRF835
9,01
1,35
0,014
0,0039
Manual_Aer 5400_EN_27-04-2023.docx
German StrlSchV §§63 u. 63a Anlage 3
5,4
0,34
in µSv/(Bqh/m³)
192
76,8
0,84
SARAD GmbH 2023
Advertisement
Table of Contents
