The power spectrum amplitude around the nine 4 K lines for the two bolometers 143-5 (upper panels) and 545-2 (lower panels). The vertical bar shows the line frequency. The spectra are obtained by averaging 200 individual ring spectra (see Sect. 5) to reduce the noise. The residual lines are at most comparable to the noise level. The signal shows up at the harmonics of the spin frequency  ≃ 0.16 Hz. In the CMB channel of the top panel, the high harmonics of the signal do not stand out against the noise, but they are clearly visible in the bottom panel. Note that the spin frequency variations between rings yield the complex signal line pattern of interleaved combs.