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v3.3.3-pre
Thursday last week there was a radiation alarm in the East secondary zone, without transmission of the alarm to the CCC. The beam was cut during about 15 minutes to solve the problem. In the afternoon the PSB beam were stopped at 13:30 for an intervention in the ring that lasted 3.5 hours. during that time in the PS we profited to exchange the pulse forming network for some extraction kicker to allow for a better quality East area beam when the parasitic TOF bunch is produced on the East cycle. Beam was back at 17:00. Also Thursday following another radiation alarm in the East secondary zones the intensity on the East cycle was decreased, but the number of cycles increased. This was possible as not all users are presently requesting beam.
From Friday onwards the East cycles were produced with the parasitic nTOF bunch.
On Saturday morning the East Area water cooling station was stopped around 08:00 for 1.5 hours. An intervention by the specialist was required. This morning a definitive repair of a flow meter will be made.
Sunday night around 03:00 for a duration of 2 hours the PSB could not deliver beam due to extraction kicker problems that required an intervention.
During the night of Sunday to Monday the Meyrin compensator tripped. Machine operation continued, but the restart later in the morning required a stop of all machines that lasted about 1 hour. Monday afternoon the East area gems were stopped for slightly more than 1 hour around 16:10 due to a problem with on of the East area septum power supplies.
Monday to Tuesday night one of the PS extraction kickers, required for nTOF broke. After initial investigation it turned out that the repair would take more time and should deb done during day time. a work around was put in place for the nTOF dedicated beam and the AD beam extraction. The kicker is not yet repaired, but the cause is now understood and will be repaired today, during the machine stop.
Tuesday afternoon the PS POPS tripped due to a fire alarm, which in the end turned out to be a false alarm, but nevertheless caused a 30 minute downtime.
Wednesday was an MD day, during which access was granted in the East Area for the work on the new CHARM/Irrad zone form 08:00 until 17:00.
Thursday mooning as planned all beams were stopped at 06:00 for cool-down for the accesses in the different machine that take place between 08:00 and 12:00,
Throughout the week the extraction of beam were perturbed on several occasion due to issues with the different extraction kickers.
The number of East cycles will be reduced to close to what was planned and the intensity per cycle will be increased to more than 2E11 to 2.5E11 per cycle in order to avoid unstable extraction of the East area spill, but to remain within the radiation limits.
Just for information the Ar. ion setting up is also progressing and Tuesday night the ions from LEIR were injected and soon after they were accelerated and extracted. Now beam adjustments will be made.
East Area:
Lau mentions that the radiation alarms were triggered by the high number of protons in the target area, rather than from the T9 beam. From the high intensity run with 2 spills only for the Charm IC, also triggers the radiation alarms, at the time of the spills. The integration time of the RP detectors could be adabted to not trigger on single spills.
T9: Samir showed slides on the use of the AIDA telescope by the Clicpix group. The special run for the Charm IC went fine (reaching 8E5pps). Totem is installing its small diamond/Si monopixels to check which combination of detectors and front ends give best timing performances. The ATLAS NSW dismantled yesterday.
The INSULAB team arrives at CERN Sunday. They will start installing monday morning. The AIDA telescope will be moved out of the beam and, the other seutps out of the zone.
T10: Oleg reported the COMPASS RICH is installing, everything on track.
nTOF: Many interventions during office hours (2 facilties). A low intensity run will be needed for a night. RF noise is observed in both EAR1 and EAR2, however not the same. It doesn't seem to come from the machine. Other neighbouring RF sources are being investigated.
Safety: the overall safety awarness is good. Please mind the standard causes of accident, droping, falling,circulation...
Lau reminded that RP checks are mandatory for material exiting the experimental area, and they can be requested throug EDH transport (internal to CERN) or shipping ( leaving CERN) requests.
AOB: