Fluke Biomedical 6000-528 - Manual (Page 13)

Maintenance, Calibration, and Troubleshooting
Maintenance
4
4-1
NOTE
Section 4
Maintenance, Calibration and Troubleshooting
4.1 Maintenance
The Model 6000-528 Ion Chamber requires no routine maintenance, other than routine inspection of the
chamber
for damage.
4.2 Calibration
The Model 6000-528 is not factory calibrated (although factory calibration is available). You may easily
calibrate the 6000-528 using the internal NERO® or 4000 chamber as a standard.
4.2.1 Calibration with a NERO 6000B or 6000M
1. Calibration will be performed on a standard radiographic x-ray machine. Set the machine to 100
kVp, 300 mA, 0.5 sec. Place the Model 6000-528 External Ion Chamber on the table and use a
distance of 40 inches. Collimate so as to uniformly irradiate the entire ion chamber.
2. Attach the Model 6000-528 External Ion Chamber to the NERO detector by connecting the BNC
connector to the appropriate jack on the back, then plug the banana plug into its mating jack.
Position the NERO detector such that no radiation will fall upon it. Connect the NERO detector to
the readout unit via the detector cable, plug into AC power and turn the unit on.
The NERO detector must be located out of the
radiation beam. The Model 6000-528 External Ion
Chamber is wired in parallel with the internal ion
chamber; therefore, any radiation falling on the
internal ion chamber will affect the reading. Shield if
necessary.
3. Verify the mR correction factor by pressing the key sequence, "F mR". The correction factor should
appear on the LCD. If it is not 1.000, enter 1 and press ENT.
4. To set up for an exposure, press “F-5". The display will clear as NERO measures electrometer drift
for twelve seconds. The NERO will beep and display "0.0 mR". Make an exposure, and record the
results. Press "NEXT" to clear the display and repeat. Make a total of five exposures in this manner.
All five should be within ± 3%. Compute an average and label it "Measured". Press "EXIT" to return
to the "Ready" condition.
5. Remove and disconnect the Model 6000-528 External Ion Chamber, and place the NERO detector
in the center of the beam. Raise the tube 2.25 inches to compensate for the height of the detector
box.
6. Make five exposures using the NERO detector in a similar manner as you did in step 4. Again all
five readings should be within ± 3%. Compute an average and label it "True".