Checking the spectras with only the test beam using raw ADC data and no scanning:

- Spectra are flat at frequencies above 20 MHz with exception of the expected peaks at 56 MHz and 112 MHz.

- The Noise levels agree with expectation.

- Below 20 MHz there are structures between 7 MHz and 9 MHz, as well as between 1 MHz and 5 MHz. Similar structures are visible both on the B4 and the B1p PC. They are visible with blocked beam but do not show up if the input to the ADC is disconnected, origin is under investigation. Note that these peaks are well below the lowest demodulation frequency for the phase and intensity images (as well as derived quantites).

- On B4 a 20 MHz peak is visible, we do not know whether this peak is expected?

(- side remark: the 6 MHz peak does not show up in the PC data on B1p because during DF it did not fall on the diode)

Figure showing the mentioned observations is attached as rawadcdata.png.

Remarks on the raw demodulated signals:

The signals obtained with the PC follow the trend of the main diodes. However, there are discrepancies which could be caused by a moving beam spot (the diode of the PC is much smaller than the beam spot) and are therefore of limited use (unless integrated over a scan which we did not do). Figure showing the mentioned trend is rawdemodulated.png.