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„Disable auto alert reset"
„Alert confirmation" *)
*) If "Disable auto alert reset" is activated, the alert always appears in the menu list independent on
status of "Alert confirmation".
After delivery, following alerts are pre-defined:
Alert source
Alpha dose
Beta dose
Flow rate
Filter stepping drive
(optical sensor)
Filter stepping drive
(Motor signal)
The green light signalizes the proper operation of the instrument and will light only if sampling is
started. The configuration procedure for alerts will be explained in the chapter "User specific
settings".
9. Gamma background compensation for the beta channel
Increased background radiation results in an increased count rate for betas. The reason is the
generation of conversion electrons by interaction of gamma quants with matter (e.g. detector
housing). These conversion electrons cannot be distinguished physically from the electrons emitted
by the collected aerosols. Thus, the instrument would show a beta exposure even if no air-born
aerosols are present. This "virtual" exposure disappears as soon as the instrument leaves the gamma
radiation field while the real collected filter activity cannot decrease.
9. 1. Static gamma background compensation
The standard instrument offers the possibility of static background compensation if the gamma
radiation field on site is known (work place). The best way is to measure the background count rate
directly with the instrument (sampling without pump). Then, the achieved value can be set as one
configuration parameter using the configuration software dCONFIG. The background count rate can
also be estimated if the local dose on site is known. For a natural radiation field, the following
formula may be used:
Background count rate = 250cpm/(µSv/h) * Dose rate (µSv/h)
The pre-set background count rate will be subtracted from the beta gross count rate, taking the
statistical fluctuations in consideration. If the unit with pre-set background is operated in areas
without gamma radiation, the configuration needs to be changed again. Otherwise, the detection
limit would be increased.
To set the background count rate see the chapter "User specific settings".
SARAD GmbH 2023
Signal devices will be switched off after the user confirms the
X
alerts by the associated menu function.
Signal devices will be switched off if the alert situation is no longer
-
present.
X
The alerts appear in the menu list for confirmation.
-
The alerts do not appear in the menu list for alert confirmation.
Signal/check period
Red/Interval
Red/Interval
Yellow
Yellow
Stop sampling
Manual_Aer 5400_EN_27-04-2023.docx
Pre-set threshold
> 2.5DACh
> 2.5DACh
< 15Lpm
> 5s
> 1s
Aer 5400
Displayed phrase
Aerosols
Aerosols
Flowmeter
Filter status
Motor
15
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