Polimaster PM1403, Руководство по эксплуатации, Страница: 28 / 29

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7.2.3 Search mode of  - β- radiation sources
To search  - β- radiation sources: connect BDAB to Display and Control Unit РМ1403 and
enter the menu indication mode
When the "α Search Mode" line is selected, or "β Search Mode" line is selected, Figure 7.4 (1),
BDAB enters the test mode. Upon testing BDAB automatically enters the background calibration
mode. Remove the γ- -filter after the calibration. When the calibration is finished, BDAB enters the
search mode of
 - radiation sources, Figure 7.6 (1) or β- radiation, Figure 7.6 (2).
If impulses count rate exceeds upper measurement range when BDAB is working in the
search mode, LCD of Display and Control Unit РМ1403 will display “OVL".
1) 2) 3)
Figure 7.6
In the search mode the current value of average count rate of impulses coming from BDAB is
calculated and displayed in cps in the upper line on the LCD of Display and Control Unit РМ1403.
Statistical error is displayed in percents with 0.95 probability under indicated measurement
units on LCD of Display and Control Unit РМ1403 (to the right). User can read the measured value
when the statistical error is 10 % or less.
Current value of count rate is compared to the operation threshold calculated in the calibration
mode. If current value of count rate exceeds the threshold value, then light, sound (audio), and vibro
alarms are activated. Alarm signals repetition rate increases when the instrument gets closer to the
 -
β- radiation source, i.e. when the threshold is exceeded more and more.
Operation threshold can be changed by setting a new
n
coefficient within 1.0 – 9.9 range.
N
coefficient influences the operation threshold value – the lower the n coefficient is, the higher
instrument sensitivity is. Note that the instrument false response rate increases at that.
Use “Save” to record measurement results into memory of Display and Control Unit РМ1403.
Search mode of
 - β- radiation sources enables the following, Figure 7.6 (3):
− start measurement of count rate and DER – "Clear Statistic";
− do calibration ("Calibration"). When the "Calibration" line is selected, BDAB will
recalibrate, and then switch to the search mode automatically;
− switch sound alarm On/Off – "Sound On / Off";
− set detection threshold – "Threshold α";
– view information on BDAB (serial number and software version) – “Detector".
7.3 BDAB settings
BDAB operation settings are configured from the menu of the corresponding mode, see items
7.2.1 – 7.2.3.