How often should I send my electrometer in for calibration?
The IEC (International Electrotechnical Commission) recommends electrometer calibration every two years to assure optimal performance.
IEC 60731 – Medical electrical equipment – Dosimeters with ion chambers such as used in radiotherapy.
IEC 61674 – Medical electrical equipment – Dosimeters with ion chambers and/or semi-conductor detectors as used in X-ray diagnostic imaging.
Standard Imaging can coordinate your calibration at an accredited ADCL, but also provides free inspection and testing services, as well as expedited repair service, if necessary. Our goal is a two-week turnaround upon receipt of equipment, although actual time may vary depending on the ADCL. Request Service »
At what times should I zero my electrometer?
Zeroing should be performed after the signal level stabilizes following any of the changes listed below (see electrometer user manual for specific instructions):
At system startup, after completion of warm-up sequence
When a new range of operation (high or low) is selected
After a chamber is connected and is allowed at least 5 minutes to stabilize
After any time a significant change is made to temperature, pressure, or movement in the system setup
Each component (chamber, extension cable, etc.) added to the system may introduce an offset to the signal level. When the system stabilizes, perform a system zero to clear this offset. Do not perform a system zero if signal level trends in either direction, wait until a stable signal level is achieved before performing a system zero.
In general, how do I properly zero the electrometer + extension cable + ion chamber system?
Note: These instructions apply to usage with Standard Imaging electrometers. Please refer to your electrometer’s documentation for specific details.
With nothing connected to the input jack of the electrometer and the dust cap on, turn the power on and wait for the electrometer’s designated warm up time.
If applicable, select the desired operating range as described in the electrometer’s user manual.
Perform a system zero as described in the electrometer’s user manual.
Connect the ion chamber (and extension cable, if used) to the electrometer and select the desired voltage bias. Allow at least 10 minutes for the system to stabilize.
Verify the leakage of the ion chamber is within the manufacturer’s stated acceptable limits.
Repeat the zeroing process as in step 3, but now with the ion chamber (and extension cable, if used) connected.