QZFM calibration>1.5

[Mansi Tarani]

We are using QZFM UI V7.6.2 inside twinleaf magnetic shield ( degaussed). After doing field zero on, we are not getting very high B0, By and Bz value ( order of few tens of nT) but calibration value is quite high i.e.., greater than 1.5. I want to know possible reasons for this and also the steps which we can take to troubleshoot.

[James Osborne]

Hi Mansi,

Those calibration factors are within normal range for triaxial sensors. We generally say that dual axis calibrations should be less than about 1.5 and triaxial calibrations should be less than about 3.0. However it is important to note that higher calibrations do not mean the sensor cannot still be performing with good sensitivity, calibration factors are used to indicate that the sensor is in a proper environment and fully operational.

If the sensor noise floor is higher than expected (observable in the PSD graph in the UI), then I can provide further assistance for the next steps. Please let me know if this is the case or if you have any other questions. 

Best regards,

James 

[Mansi Tarani]

Thank you very much, in same setup, I am facing another problem, there is a lot of noise (very large random fluctuations) in z channel, because of which, it is difficult to observe Z magnetization. I’ve attached X, Y, and Z traces recorded with no applied field. I want to know, what steps can I take to reduce this noise.

Thank you

Mansi

[James Osborne]

Hi Mansi,

There are a few possibilities for what might be causing the noise on the z-axis. We need to determine if this noise is from the environment or from the sensor, would you have the ability to rotate the z-axis of the sensor by 90 degrees (so that the z-axis now points in the x or y direction) to check if the source of the fluctuations is from the environment? If we can confirm the environment is not the source of these fluctuations, then the issue may caused by a loose connection in the cable and you can carefully reconnect the sensor head to the ribbon cable (be sure to first power off the sensor electronics module and take basic ESD precautions to avoid damage to the laser when disconnecting/reconnecting the sensor).  Please let me know if you need further assistance.

Best regards,

James