Capintec CRC-712MH, Руководство пользователя

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CAPINTEC, INC. CRC
®
-712MH
Background Adjustment
This procedure should be performed at least once every day the instrument is used. It
is important to understand that this function does not provide a quantitative
measurement of background radiation. The value indicated on the display when the
BKG push-button is depressed is the relative change in background radiation since
the last adjustment.
1. Ensure that there are no radioisotopes (especially the sample to be
measured) or other radiation sources near the calibrator.
2. Press the BKG push-button and verify that the background level is
satisfactory; if not, continue on with Step 3.
3. Unlock the Background Control Knob, adjust the background control until the
displayed reading is 0000mCi (±0005) and re-lock the control.
Instrument Functioning Test (Battery Test)
1. Ensure that there are no unusual radiation sources near the instrument.
2. Press the TEST push-button. The display should indicate between 140 and
180 volts.
Note: On the CRC
®
-712MH, use the Chamber Selector Switch to verify the
battery voltage for each chamber.
3. Record the display reading.
The reading should be constant to within ±2 volts and never vary more than ±5 volts
from one day to the next, under constant operating conditions. When the voltage
decreases to below 140 volts the battery should be replaced.
Contamination Test (Sample Holder)
1. Remove the sample holder from the well.
2. Perform the Background Adjustment procedure.
3. Press the OTHER push-button and set the Calibration Control to 030 .
4. Insert the Sample Holder (empty) into the well and note the displayed reading.
5. If the reading exceeds .0010mCi (0.5MBq), the Sample Holder has been
contaminated and should be replaced.
6. If the contamination is within allowable limits, perform the Background
Adjustment (see step 2) to compensate for the activity of the Sample Holder.
Note: The Chamber Well Liner should be tested similarly if contamination is
suspected.
CAUTION
Never use the calibrator without the well liner in place. Liners are inexpensive and easy to
replace. A contaminated chamber is a very costly mistake. If the unit becomes contaminated
remove the liner and clean the unit as stated in CHAPTER 7: CLEANING AND
MAINTENANCE before operating.
5 - 2 QUALITY ASSURANCE & ACCEPTANCE TESTING December 09