Operation
Operation Instructions 3
A reset error will not occur for ion chambers calibrated in dose rate units (i.e. Brachytherapy chambers) since the measurement is primarily concerned with amps or dose rate.
3.9.15 Reset Error (With Automatic Leakage Compensation Enabled)
The following discussion is only applicable when automatic leakage compensation is enabled and the ion chamber is calibrated in Coulombs.
Holding the RESET/MEASURE button while on the Measurement screen causes the Model 35040 Therapy Dosimeter to reset the electrometer, zero all readings, and restart the measurement process. When an exposure is detected immediately following the reset that was not present prior to the reset, the instrument displays the reset error message shown in Figure
ADCALC
Internal Reset Error
Press RESET/MEASURE
and Repeat Exposure
Figure 3-31. The Measurement screen showing the Reset Error message
To remove the error message, end the exposure and hold the RESET/MEASURE button. Wait a few seconds for the instrument to complete the reset and repeat the exposure.
3.9.16 Annunciators
The top line of the display is dedicated to status annunciators. The Model 35040 Therapy Dosimeter continuously monitors the ion chamber bias and battery voltages. If either one of these values is outside the specified range, the Model 35040 displays an annunciator to indicate the error. Table
Table 3-2. Annunciators
Annunciator | Condition | |
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| |
??Bias | No bias measurement possible since the electrometer is not ready | |
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| |
ADC | Air density correction in use (only applicable to radiological | |
measurements) | ||
| ||
ALC | Automatic leakage compensation enabled | |
|
| |
LoBat | Low Battery voltage | |
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| |
LoBias | Low Bias voltage | |
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| |
HiBias | High Bias voltage | |
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| |
OvAmps | Overranged current | |
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| |
Rst | Resetting electrometer | |
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| |
Tmr | Timer in use | |
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| |
WAIT Bias Not Ready | The dosimeter is setting the bias | |
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| |
WAIT System Not Rdy | The dosimeter is resetting the electrometer (only applicable when | |
automatic leakage compensation is enabled) | ||
|