Thermo Scientific RO-20, Руководство по эксплуатации

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Ro-20 RB-XXX-XXXXXX E 4-3
Löw 08.10.2008
To calibrate,
1. Select the Zero position on the Function Switch and zero the meter.
2. Remove the plastic cover on the side of the can and position the RO-20 so that the ion
chamber is in a gamma field of known intensity.
3. Adjust the calibration control (corresponding to the Function Switch position) for the
proper meter indication.
4. For best accuracy, choose a calibration field which will cause the meter to read near
the “4” mark when calibrated.
5. Repeat the procedure for all five ranges.
6. Reinstall the plastic cover in the side of the can when finished.
Note To avoid errors, the entire ion chamber of the RO-20 must be in the gamma field when
calibrating. The effective center of the chamber is marked by indentations at the front and
sides of the case.
▲
Caution The higher radiation field strengths required for calibration of the RO-20 can cause
personal injury in a short time. Use safe procedures. ▲
4.1.4 Circuit Checks
• Flip the light switch in both directions and observe that the lamps are functional.
• Select Battery 1 position on the Function Switch and measure the voltage of the AA cells.
The meter should indicate battery voltage multiplied by 0.6, within 5%.
• Select Battery 2 position of the Function Switch and measure the voltage of the 3 ea 12V
alkaline batteries. The meter should indicate battery voltage multiplied by 0.114, within
5%.
4.1.5 Disassembly
The lower case can be separated from the assembly by unfastening the front and rear latches
and lifting the instrument from the case.
The chamber face is very thin and easily damaged, and should be protected with a covering
when the case will be turned off for an extended period.
Static-sensitive components are used on both the main circuit board and on the chamber
board. Use grounding procedures to eliminate static charges when working on the RO-20.