Fluke Biomedical 10100AT - Manual (Page 54)

10100AT
Operators Manual
3-8
such as A, R/min, or Sv/s. During operation in this mode, direct beam exposure levels are assumed.
Thus, the automatic drift and offset compensation are not required, and autoranging is limited to the
upper three sensitivity ranges. In this mode, a kVp measurement is performed along with the basic
exposure rate measurement. The display is updated at a rate of approximately once per second.
When operating in this mode, the integrator output level is monitored at 1-second intervals. The exposure
rate measurement value is based upon the amount of charge integrated during each 1-second update
period. The integrator is reset at the beginning of each sampling period. During each 1-second period
between display updates, a new 50 ms wide kV data set is acquired. The data set is analyzed using the
prefiltering and peak detection described in the previous section.
3.14 Temperature and Pressure Sensor
The Model 35050AT Dosimeter contains an integrated temperature/pressure sensor. When using the
automatic temperature and pressure sensing feature, the measured temperature is the internal
temperature of the Model 35050AT, TRIAD TnT Dosimeter. This temperature may not be the same
temperature as the Ion Chamber that is in use.
Adequate time must be allowed for the Dosimeter and Ion Chamber to reach thermal equilibrium before
automatic temperature sensing is used. For a large temperature differential, the thermal equilibrium time
of the 35050AT may be 2 hours. A 3°C change in temperature results in approximately a 1% change in
air density correction factor (ADC).
The housing of the Model 35050AT Dosimeter and its ion chambers are vented to atmospheric pressure;
as a result, there should be no difference between the atmospheric pressure measured by Model
35050AT Dosimeter and the actual atmospheric pressure of the ion chamber.
In the event that the temperature/pressure sensor becomes non functional, an error message, “Temp &
Press Error Use Manual Entry” is displayed and only the manual temperature and pressure entry mode is
available.