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MPP meeting
MPP meeting 14 April 2008
ELQA report. V. Chareyre
Sector 7-8: low voltage tests were performed last week in both DFBAs. High voltage tests are delayed by the intervention in the water cooled cables .
Sector 3-4: The high voltage tests will be done after the repair of the connection cryostat. The sector will be ready for cool-down next week.
Sector 1-2: High voltage tests followed the repair of the dipole (short on the lira).
Sector 8-1: The cooling down of the sector is delayed by 3-4 days. ElQA teams are ready to start qualification at cold.
Status of powering procedures. M. Modena
All the procedures are now at least in the draft status except for the powering procedures for correctors in the triplet and the one for powering the undulator (Action: W. Venturini). The version number will be created/updated automatically after the documents are released.
Part of the correctors in the inner triplet are not needed for the first year. The minimum list of circuits to be powered for this year run will be presented in next MPP meeting. (Action: A. Siemko) . It was noted that the MCDO magnets are also nested and are being hardware commissioned independently. Powering the two circuits together should be part of the PGC procedures for the arc .
Q5R5 level gauge. J. Casas-Cubilllos
The operational procedure to do a boil-off test was presented. MPP required a global procedure for the commissioning and acceptance of the level sensors.
A new calibrated level gauge was installed in Q5R5. This gauge has a centering ring and support in g-11 that fills almost completely the tube. It acts like a local damper for thermo-acoustic oscillations. The full piece is raised by 20 mm with respect to the nominal position.
Tests have shown that there is a 10% level reading reduction when the warm bypass to line D is open. The bypass is no longer needed as the support piece satbilises the small oscillations. However oscillations are still seen when overfilling.
The results of the boil off test for Q5R5 show a regular decrease of the level. The total time corresponds to what has been observed in other magnets but the total helium volume has not yet been checked. A. Siemko asked why there was no plateau at the maximum level. Previous tests showed that the behavior was unstable and pressure oscillations were seen.
There was a discussion to find out if there is any way to diagnose obstructions of the capillary before the cold commissioning. Tests at the lab have not been done are not foreseen. Endoscopy could be tried in warm sectors. Gauges with spacers could be used by default. It is not clear who is responsible for the level measurement. (Action: A. Siemko)
CRG proposes to control the level at 70%. The suggestion was accepted by MPP as ithis covers the superconducting parts of the cold mass. The new control level will be transmitted to CRG/OP and HC. (Action: J. Casas and M. Pojer)
Polarity issues in the inner triplets and DFBX. S. Russenschuck
S. Russenschuck reminded the rules to properly signal a change of polarity due to a rotation of a magnet by 180 degrees. The rule applied in the LHC construction was to relabel the bus-bars if a magnet was returned in the cold mass or cryo-assembly. Once the cryo-assembly was finished and if it was returned in the tunnel during installation, the software and database will take care of applying the right polarity.
Several polarity errors were discovered in the inner triplet:
A large part of the tests are done manually in the tunnel by PO experts. The current is specified for each power converter and a calculated signal has been made available by AB/CO for analysis purposes. It is not clear however how the current for each converter will be input into the control system through LSA from the optics field values (Action: A. Vergara).
The maximum current above which no access is allowed in the tunnel.
Adding the pressure conditions to the table of cryo_start and cryo_mantain signals.
A. Siemko answered that he work is ongoing.
ELQA report. V. Chareyre
Sector 7-8: low voltage tests were performed last week in both DFBAs. High voltage tests are delayed by the intervention in the water cooled cables . Sector 3-4: The high voltage tests will be done after the repair of the connection cryostat. The sector will be ready for cool-down next week.
Sector 1-2: High voltage tests followed the repair of the dipole (short on the lira).
Sector 8-1: The cooling down of the sector is delayed by 3-4 days. ElQA teams are ready to start qualification at cold.
Status of powering procedures. M. Modena
All the procedures are now at least in the draft status except for the powering procedures for correctors in the triplet and the one for powering the undulator (Action: W. Venturini). The version number will be created/updated automatically after the documents are released. Part of the correctors in the inner triplet are not needed for the first year. The minimum list of circuits to be powered for this year run will be presented in next MPP meeting. (Action: A. Siemko) . It was noted that the MCDO magnets are also nested and are being hardware commissioned independently. Powering the two circuits together should be part of the PGC procedures for the arc .
Q5R5 level gauge. J. Casas-Cubilllos
The operational procedure to do a boil-off test was presented. MPP required a global procedure for the commissioning and acceptance of the level sensors.A new calibrated level gauge was installed in Q5R5. This gauge has a centering ring and support in g-11 that fills almost completely the tube. It acts like a local damper for thermo-acoustic oscillations. The full piece is raised by 20 mm with respect to the nominal position.
Tests have shown that there is a 10% level reading reduction when the warm bypass to line D is open. The bypass is no longer needed as the support piece satbilises the small oscillations. However oscillations are still seen when overfilling.
The results of the boil off test for Q5R5 show a regular decrease of the level. The total time corresponds to what has been observed in other magnets but the total helium volume has not yet been checked. A. Siemko asked why there was no plateau at the maximum level. Previous tests showed that the behavior was unstable and pressure oscillations were seen.
There was a discussion to find out if there is any way to diagnose obstructions of the capillary before the cold commissioning. Tests at the lab have not been done are not foreseen. Endoscopy could be tried in warm sectors. Gauges with spacers could be used by default. It is not clear who is responsible for the level measurement. (Action: A. Siemko)
CRG proposes to control the level at 70%. The suggestion was accepted by MPP as ithis covers the superconducting parts of the cold mass. The new control level will be transmitted to CRG/OP and HC. (Action: J. Casas and M. Pojer)
Polarity issues in the inner triplets and DFBX. S. Russenschuck
S. Russenschuck reminded the rules to properly signal a change of polarity due to a rotation of a magnet by 180 degrees. The rule applied in the LHC construction was to relabel the bus-bars if a magnet was returned in the cold mass or cryo-assembly. Once the cryo-assembly was finished and if it was returned in the tunnel during installation, the software and database will take care of applying the right polarity. Several polarity errors were discovered in the inner triplet:
- Polarity errors in the MCOX and MCSSX magnets. They affect all the triplets and are corrected in the patch panel in the DFBX. There is no impact in the QPS system as the magnets are protected by the power converter diode.
- The cable routing for the MQSX is crossed in the DFBX. This also occurs in all triplets and has been fixed in the patch panel. However it does impact QPS protection. A software fix has been implemented by QPS.
- Pin-out of the 120 A corrector leads is wrong for all triplets. It has been fixed by modifying the connector of the proximity equipment.
- The polarity of MCSX was reversed only in DFBXG (8L). It has been corrected in the patch panel.
- The inversion of the 6kA leads in the tunnel applies also to all triplets. It was fixed at the level of the water-cooled cables either at the PC extremity or in the DFBX. The routing of voltage taps for QPS was modified accordingly and documented in the database.
Inner triplet powering procedures. N. Catalan Lasheras
The procedures for the powering of the main circuit in the inner triplet were presented to the members of the panel. The procedure contains all the type tests done for other circuits in sectors 7-8 and 4-5 and will surely be updated after the powering of the triplet in R5.A large part of the tests are done manually in the tunnel by PO experts. The current is specified for each power converter and a calculated signal has been made available by AB/CO for analysis purposes. It is not clear however how the current for each converter will be input into the control system through LSA from the optics field values (Action: A. Vergara).
MPP-CCC rotation plan. N. catalan Lasheras
A draft of the plan for the MPP-CCC team was prepared based on the availability of the members during the summer. As powering of several sectors is starting in two weeks time, it was suggested to add a member of the team in the CCC working on normal hours. The draft will be distributed for final changes during this week.AOB
M. Solfaroli Camillocci reminded the panel of two issues to be clarified as a result of the hardware commissioning review.The maximum current above which no access is allowed in the tunnel.
Adding the pressure conditions to the table of cryo_start and cryo_mantain signals.
A. Siemko answered that he work is ongoing.
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