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107th BLM Thresholds WG meeting (Preparation of IR3 MD)
Participants: S.Morales, A.Lechner, B.Salvachua, D.Mirarchi, A.Verweij, K.Taylor, S.Redaelli, F.Titz, H.Timko, E.Carosotti
Updated procedure of MD#15209 - D.Mirarchi
- Two main updates wrt MD1
- Only partial scraping to avoid triggering BPM interlock on bunch intensity
- Need to inject more bunches than initially planned
- For 200kW -> 54 or 28 bunches of 1.6e11p depending if we scrape down to 1sigma or 0.5sigma
- For 500kW -> 136 or 70 bunches of 1.6e11p depending if we scrape down to 1sigma or 0.5sigma
- Need to inject more bunches than initially planned
- Need to inject trains to have an efficient filling-> request to have trains of 36b
- Only partial scraping to avoid triggering BPM interlock on bunch intensity
- No changes on BPM.6 interlock window is necessary
- Interlock on max RF offset must be increased -> nominal + 400Hz (needed RF shift of +400Hz)
- Dedicated BLM thresholds deployed just before the MD
- Updated BLM decomposition matrix for 2025 to be loaded on LSA
- Typical BIS mask of loss maps
- Main focus on B2 -> off-momentum losses in B1 are caught in IR7 at start of ramp
- Gradual approach with higher intensities injected until achieved target power loss
- Will try to adjust loss rate speed and sustain target power loss for some seconds
- Belen comments that we should test at low intensity if there are any interlocks triggering
- Daniele says that for the sake of efficiency, it is better to mask the first test with setup beam
- Belen comments that for unforeseen limitations, we will not change the thresholds
- Belen asks Stefano if someone from collimation could be present to check temperatures of collimators, magnets, etc
- Anton says there might be a dump on the passive absorber as it gets much more loaded than the case in IR7
- Q6 IR3 operating at low current -> Arjan confirms there is no problem with doing the test for this magnet
- Implementation of thresholds can be done as soon as the previous MD dumps
BLM thresholds changes for MD#15209 - B.Salvachua
- Implementation of offline changes after the meeting
- Q6 quench levels much lower than MQY/MQM
- About a factor of 10 lower
- Conclusion from Arjan was that if the magnet is running at low current it is ok to probe the quench limit
- It is the case for injection energy
- IR3 TCLA at 450GeV expected power deposition below IR7 TCLA at 6.8TeV -> ok from thermomechanical simulation point of view -> Federico and Luisa
- Pierre said that there was significant margin at 500kW found on the studies of power dissipation
- OK to probe the limit for 500kW
- Analysis for rise of thresholds done for start of ramp fills from 18th to 20th of August
- Anton comments that we could think of a similar test with B1 next year without the phase knob
- TCTPV in IR2 needs a factor of 4 increase -> higher than what we had in the ion run
- In IR3 the BLM at the Q6 is the one requiring the highest factor -> around 10
- Some BLMs that appear requiring an increase are expected to be due to the scaling of B1 (which will not be used in the test)
- The TCP needs a correction in the short RS -> will require an increase of master thresholds and MF
- Scaling from pilot beam test with the RF trim will include a large error due to low BLM signals
- BLMs in IR8 will be neglected -> due to injection protection in
- A factor of 2 higher on the pilot beam scaling, it seems probable to a be a scaling error
- Will not be included in the changes
- Applied threshold on TCTPV IR2 is still lower than what was in the ion run -> acceptable
- Scaling based on the largest factor needed for the RS
- TCP threshold same order of magnitude as in IP7
- TCSG threshold slightly higher than IP7 at top energy
- TCLA not including the ones from B1 -> threshold comparable with the expected from simulations
- Rest of proposed thresholds as expected
- Q6 a factor of 10 higher -> what we want to probe
- Stefano comments that if there are unexpected interlocks from collimator temperature they should not be changed in the night
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