\begin{figure}[tbp]
	\centering
	\includegraphics[width=13.5cm]{Images/ctrl-thscan}
	\caption{An off-beam threshold scan for VFAT2 channels}
	\label{off-th-img}
\end{figure}
Preliminary noise measurements were performed in the laboratory through a threshold scan, sending commands to a \textit{turbo} card to control VFAT2 chips. This means that the number of hits was measured as a function of VFAT2 threshold, collecting $10,000$ triggers for each threshold bin. A LabVIEW tool was programmed for this purpose.\\

The detector was totally shielded by a kapton copper-clad foil. A ground plane was spread close to the hybrids in order to achieve a noise level compatible with the expected signals.\\

Threshold scans were performed for all channels of the VFAT2 chips connected to the large GEM detector. We found some disconnected channels and some noisy ones; however, the ground layer enclosing the chips generally reduced the noise fairly well. Indeed most of the channels showed noise levels similar to those visible in \figurename~\vref{off-th-img}. This means that a threshold $th \geq 35$ \textit{VFAT2 DAC step bins} should cut off all of the noise. Yet, subsequent on-beam results still had low noise levels at threshold $40ds$. The reason for few noise hits still showing up at that threshold level during the test beam, but not in the lab tests, might be that, during the test beam, the high voltage was turned on.\\

A more thorough analysis of the noise level was done by acquiring \textbf{S-Curve}s, using the internal calibration pulse of the chips: see more on this in \chaptername~\vref{ch-pad_d}.