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Weekly meeting on Xboxes
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18/3-008 - CLIC Meeting room (CERN)
Description
https://cern.zoom.us/j/6910405761
Weekly meeting on Xboxes
Zoom Meeting ID
64847033219
Host
Nuria Catalan Lasheras
Alternative host
Marçà Boronat
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Attending: Paz Alonso Arias (PAA), Nuria Catalan Las Heras (NCLH), Mareike Wendelmuth (MW), Walter Wuensch (WW), Matteo Volpi (MV), Igor Syratchev (IS), Anisullah Baig (AB)
General comments on logistics for High Gradient workshop. MV informs he will be visiting CERN in October. Asking for accommodation for his student (?) in CERN Hostel in Meryin site.
Update on XBox in Melbourne. MV comments on Canon response about windows. IS ask for VNA files of ceramic windows S-matrix, and send also to PAA. MV highlights that VNA is broken, as it does not measure below -30dB. He has to send it back to fix it. Conclusion on window: remove broken window.
WW asks if they have enough space for the laser, MV to check if they have enough space in the room. Radiation monitors just arrived. The interlock crate is in integration.
Update on CERN XBOXES. PAA comments on difficulty of changing to structure B, due to complexity of LabView code. Line PSIB still needs to be calibrated. Should be operative today.
MW summarises her last analysis. There was a discussion on how DC changes exponentially with the power. IS comments that threshold should move with the power -- WW says that to do that mathematically is very tough. PAA confirms that to do that a major change on Labview code must be done (it is not done on the go, automatically). A daily change of the threshold could be done instead, according to DUT Setpoint.
MW comments on DC distribution in terms of input power and pulse length. WW says that it seems to be an issue with scale, as DC up (positive) is always opposite direction to DC down (negative values). MW to check this. We discuss about conditions, as it seems short pulses were only used early in the conditioning process. We only went to higher powers with the longer pulses. NCLH suggests to add DC curve in the global trend plot to compare and confirm if DC goes down as conditioning progresses. MV comments on David thesis on dark current (Victoria and Marca plots). MV says he can send chapter to PAA and MW.
Discussion on filling time, which is about 60 ns, and BD w/o BDC. WW says that violating filling time of structure, BD without BDC are likely to be produced by something that is not the accelerating structure. IS says that structure should be breaking down at front, not at the end. WW asks how sure is MW about zero. MW confirms is not a perfect 0, accuracy is difficult, as she has to align signals. WW asks to check phase of reflected signal.
NClH asks if green points (BD w/o BDC) represent missing energy, as it seems to be a systematic difference between BD w BDC and w/o BDC. IS says that missing energy is same, does not depend on input power. Attention: first part of plot refers to not conditioned structure, so valued change when its finally conditioned.
WW explains that missing energy is expected when the arc is forming, where you see absorption. When arc is fully form, all is reflected. We will not have missing energy at beginning and end. WW suggests to MW to look at single pulses for missing energy, than doing statistics. Suggested plot: missing energy as function of time during the pulse, to see different curves and see how missing energy is distributed in a certain time interval.
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