Fluke Biomedical 8000 Victoreen - Manual (Page 42)

Victoreen 8000
Operators Manual
2-30
As a power saving feature, the NERO mAx’s display backlight turns off after one minute of no activity.
The backlight turns back on when any button is pressed or an exposure is made. In addition, after five
minutes of no activity, the NERO mAx exits from any measurement mode and returns to the mode
selection screen.
2.5.6 Exp Mode
Exposure mode is used to make exposure and rate measurements using the NERO mAx’s internal ion
chamber or an external ion chamber. The exposure is calculated using the selected ion chamber’s
calibration factor (along with air density correction). For more information about entry and storage of ion
chamber calibration factors, see CAL mode. For more information about selecting exposure/rate units,
see SETUP mode. All exposure and rate measurements are corrected for user entered air density. For
more information about entering air density data, see SETUP mode.
Exposure and rate measurements made with the NERO mAx’s internal ion chamber in this mode are
calculated using a constant calibration factor and air density correction. In measurement modes where
kV is measured, exposure and rate are calculated using calibration factors based upon the measured kV.
In the exposure mode, no kV measurements are made, so a constant is used to calculate exposure and
rate. The constant that is used is based upon the calibration factors corresponding to a measured kVp
average of 80 kVp. A user entered calibration factor (multiplier) allows the user to adjust the calibration of
the internal ion chamber. The default for this calibration factor is 1.00 E+00. For more information about
entry and storage of ion chamber calibration factors, see CAL mode. For more information about entry of
air density information (temperature and pressure), see SETUP mode.
Exposure and rate measurements made with the external ion chambers are calculated using the stored
calibration factor (R/nC or Gy/nC) for the selected external chamber and air density correction. For more
information about entry of air density information (temperature and pressure), see SETUP mode.
To make an exposure or rate measurement
Make sure that the NERO mAx is turned off. Plug one end of the NERO mAx’s detector cable into the
NERO mAx detector. Plug the other end of the detector cable into the NERO mAx’s detector connector.
No filter card is required for exposure or rate measurements. If using an external ion chamber, plug the
ion chamber’s BNC connector into the ion chamber signal input at the rear of the NERO mAx detector.
Plug the chamber’s bias plug (banana jack) into the bias output at the rear of the NERO mAx detector.
Position the ion chamber as needed. If using the NERO mAx’s internal ion chamber, position the NERO
mAx detector as needed.
WARNING
An electric shock hazard exists between the ion
chamber bias connector and ground.
If results are to be printed, plug the printer cable into the printer port at the rear of the NERO mAx then
plug the other end of the printer cable into the printer and turn the printer on (see Section 1.5--Printing).
Plug the AC adapter into the NERO mAx if needed (see Section 1.4--Battery Operation and Charging)
and turn the instrument on.