Using the data measured yesterday (klog 22217), I calculated the calibration factor between the output of seismometer on the ground (2nd floor) SEIS and the term (GEO-LVDT).

Per klog 20873, the aim is to calculate a such that a * SEIS = GEO-LVDT, in a frequency range where there is high coherence (Fig. 1). The value of a was calculated by minimizing the RMS value of the function  (GEO-LVDT) - a * SEIS.

The results are as follows:

• Frequency range: from 160 to 500 mHz.
• IP-L, Y Arm: a = 1.21104 (Fig. 2).
• IP-T, X Arm: a =  1.17220 (Fig. 3).

These calibration factors still need to be written in the appropriate filter banks, and then the performance of the sensor correction can be assessed.