PXD Operation (Hua Ye, Felix B. Mueller, Bjoern Spruck, Simon Reiter):
Beam incident on May 28:
1/9 modules (unit 34-1071) is still excluded from the data taking, the other eight are in operation and are taking data, although with increased currents mostly into the clear node.
Extensive tests have been performed and are documented at https://confluence.desy.de/display/BI/PXD+Tests+after+Incident+on+28.05.2019. Discussions and interpretation of the results are still ongoing. There is no definite conclusion yet, but it seems that the sensors did not suffer and that the increased currents are within the switcher chips. For module 1071 tests are ongoing to include part of the module into the data taking either by masking the affected regions on the module in software or skipping the read-out of these channels by modification of the rolling shutter sequence.
Link drop on module 1024:
The off-module data link for 1/4 DHPTs dropped on June 3. The output of the optical transmitter was checked and a degradation of the light amplitude was detected. The reason is unclear at the moment. It could be a degradation of the optical interface of the optical fibers or radiation damage of the transmitter at the dock-box. Due to lack of time during the maintenance day, not all links of all modules could be tested. This will be done at the next occasion to conclude, if the dock-box PCBs with the optical transmitters will have to be replaced during summer shut down.
HV issue on module 1031:
The back plane voltage (HV) is always at -80V, although a different value was set. This is most likely a power supply problem and currently also under investigation. At the moment there is no danger for the module and it is included in the operation.
DAQ:
Event selection by HLT has been successfully verified through ONSEN firmware. The reduction factor fits the expected values.
DHH firmware (Igor Konorov, Stefan Huber):
Occasional loss of data (aka "occupancy drop"):
The root cause of the data loss at high occupancy and under certain combinations of trigger rates is still under investigation together with DHPT experts at Bonn. The current work-around is the deployment of more relaxed veto and trigger hold-off times after injection.
As soon as the gated mode is ready for implementation at the experiment, at least the high occupancy from the injections is suppressed. In case of bursts during normal operation, during summer shutdown a DHPT reset procedure without stopping the run will be tested.
Gated mode tests at the DESY system:
The DHH side the gated mode operation of the full trigger and signal chain via the FTSW has been verified. Final preparations are being done, mostly from module side, before the first tests at the KEK system.
PXD 2020:
Sensors (Rainer Richter):
PXD9-20a: The back etching (thinning) of the process wafers is ongoing, still at step 1/13 of phase3.
PXD9-20b: at step 21/22 of phase2
PXD9-21: at step 12/13 of phase1 (runs at low priority as backup)
Module testing queue:
MPP: W04_OB1, W10_OB1, W02_OF1, W09_OF2 (after SWB rework)
- W02_OF1 is still under characterization, no news this week
GOE: W05_OF1
- no news this week
HLL: W04_OF1
- no news this week
Phase 2 modules:
at Bonn:
W37_OF1: ready for ladder assembly after beam test
W37_IF: no news this week
at HLL:
W46-IB and W37-OB: ready for distribution to test sites
Assembly of new L1 modules:
Due to the Switcher issue, the assembly is on hold. While we are waiting to get the new Switcher chips from AMS, IZM started the preparation of the steps for the bumping on chip level. The order for bumping is out and IZM is preparing the support wafer for the bumping process.
Ladder Assembly (Hans-Guenther Moser):
The report for the reviewers has been sent out. Ladder assembly will be resumed June 17, after return of the technician from vacation.