BRATOL monthly meeting
CERN
Monthly meeting on the advancement of the BI-EP collaboration for the development of the BI rad-tol optical links
The meeting was mostly focused on the reharsal of the presentation of Antonio for TWEPP.
The presentation was in a preliminary/draft status.
A new reharsal will be held next week and BI will be invitated, but in case it would be not possible for the BPM or BLM team to aprticipate slides will be sent to the BRATOL community.
During the presentation one of the open questions from previous meetings was answered: the sum of all the possible effects inducing wavelenght a wavelenght shift will not bring the TOSAs out of the MUX acceptance window for any of the crntral frequencies.
It was re-stated that for acceptance of the components it is important to have an estimate of the expected flux <= action on Christos for the SPS BLM
Antonio tested the CTTx in a climatic chamber at 60 degrees, current operating conditions of the VTRx in the SPS in closed boxex (system used as reference for worse case scenario). The transmitters in those conditions were measured at 70 degrees, a temperature that might impact their reliability but at which the work. Andrea stated that 60 degrees is the absolute maximum and to be considered in case of no ventilation/ventilation failure for the LHC BPM system. Christos comented that for the BLM the alarm is at 55 degrees and a second one is triggered at 65 degrees but neither is ever triggered.
The expected expenses/orders expected to be commited for this year will be provided by Antonio with details on which BC the orders will be charged.
Andrea asked about the status of the refurbishment of the missing BPM's VTRx from the previous production. After some exchanges Jan confirmed that it could be possible to find a way to have at least 40 pieces refurbished.
Due to an apparent confusion on this topic, Manoel and Andrea traced back after the meeting the historic of the issue via email exchanges with Jan and Lauri. A summary is below:
- BPM and BLM bought 500 SM-VTRx each
- 304 were delivered to the BPM team in 2017 (196 left for BPMs)
- 50 VTRx were given to the BGI team from the BPM stock with BPM agreement in 2019 (146 left for BPMs)
- 25 VTRx were sold by the BPM team to ALICE in 2020 (121 left for the BPMs)
- 100 were delivered to the BLM team in 2021 (400 left for the BLM)
- 80 VTRx were sold by the BLM to ALICE in 2021 (320 left for the BLM)
- 30 VTRx were delivered to the BPM in 2022 (91 left for the BPM)
- 300 repackeaged in metal VTRx were delivered to the BLM team in 2022 (20 left for the BLM)
- in 2023 BPM asked their remaining components (91) but only 21 were delivered because after BI and ESE investigation it was discovered that:
- 40 were given to ALICE without informing BI
- the yeld of the BLM repackaging was such that to provide the 300 delivered 371 'original' VTRx were used 51 more than in the BLM stock
- the 51 missing VTRx were taken from the BPM stock without informing the BPM team
The BPM team will not need all the missing 70 VTRx from their stock: 40 is the very minimum required to have a sufficient spare stock for the operational systems using those devices.