Analysis of Voltage Jumps In LFI18 R0D0-R0D1 and LFI26 R1D0-R1D1 and debug procedure on LFI 26 during OD204

Abstract

This note was aimed at debugging the two features observed during OD 184-185 and OD 188 on channels LFI 26 and LFI18. A dedicated procedure for debugging the LFI 26 issue was also proposed, performed and analyzed in this report. The two features exhibited as Scientific Voltage jumps both on REF and SKY signals of the two coupled diodes, as reported in the table below. In the case of channel LFI 26 the signal increased suddenly on both sky and ref without decreasing again. In the case of LFI 18 the signal decreased again. While the behaviour of LFI 18 was fully understood just from the analysis of the available data, for LFI 26 it was necessary to wait for the proposed extra test, run many days after the event. Results from this dedicated test are reported in the second part of this note.