13/10/2021

Due to the problem of finding the signal with the first BPM in the linac  LI/DG/BPM.01-LIB.01, it was decided to do the tests with the signal generator (500 MHz sine wave cw, ~100 mV).Eventually, we found that the cables (or tango names in the control room) of that BPM in the linac LI/DG/BPM.01-LIB.01 and the BPM in the EL EL/DG/BPM.01-LIB.01 were swapped.

We change the cabling the tha rack between these two BPMs, now in the control room, the tango names correspond to the nomenclature for ER/DG/RAC.05-LIB-01. What about the calibration constants in this case? To be discussed !!!!

Once the cabling was fixed, we saw well the sin signal on the libera (see the screenshot attached).

We also check the ER/DG/RAC.05-LIB-02 with the generator since there there is one TL BPM TL/DG/BPM.01-LIB.02 we will need as well for this phase of the commissioning. We found also that two BPM modules are swapped with respect to tango names used in the control room. Here it is the summary:

- in the rack5  (sticker TL/01, serial number S/N 11) corresponds well to TL/DG/BPM.01-LIB.02 in the control room =>>>> OK 

- in the rack5  (sticker TL/02, serial number S/N 4) corresponds to TL/DG/BPM.01-LIB.03 in the control room  =>>>> to be corrected  !!!!!!!

- in the rack5  (sticker TL/03, serial number S/N 18) corresponds to TL/DG/BPM.01-LIB.02 in the control room  =>>>> to be corrected  !!!!!!!

- in the rack5  (sticker TL/04, serial number S/N 16) corresponds well to TL/DG/BPM.01-LIB.04 in the control room =>>>> OK 

Now, we are ready to restart again with the beam (we are waiting when there will be a beam at ThomX). 

=>  need to play with the trigger delay but hopefully we will see the signal on the libera this time.

The similar tests with the generator should be done for the rest of the liberas (ER/DG/RAC.05-LIB-03, ER/DG/RAC.05-LIB-04, ER/DG/RAC.05-LIB-05) in order to eliminate such problem in the future for rest of the BPMs.

Recommendation from N. Hubert: look at the TbT signals as well during the commissioning.