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MPP meeting
Participants
Andrzej SIEMKO
Antonio Perin
Antonio Vergara Fernandez
Arjan Verweij
Boris Bellesia
Carlos Fernandez Robles
Elena Solfaroli Camillocci
Giorgio D'Angelo
Glyn Kirby
Juan Casas-Cubillos
Knud Dahlerup-Petersen
Maria Paz Casas Lino
Marta Bajko
Michele Modena
Mikko Karppinen
Nuria Catalan Lasheras
Pierre Strubin
Reiner Denz
Richard Mompo
Rob van Weelderen
Rob Wolf
Robert Henry Flora
Roberto Saban
Rüdiger Schmidt
Sandor Feher
Thiesen Hugues
Vittorio Remondino
MPP meeting 7 May 2008
R. Denz reported that the testing of interlocks and quench heaters in sector 7-8 has been successfully done for RQF and RQD circuits and is being performed for the L8 magnets. A problem has been detected in the B21L8 dipole where one of the four heater discharges shows an abnormal decay. Direct measurements from the IFS shows a high resistance of the quench heater. G. Kirby showed that a similar problem was seen last year in Q4.L8 where the wire connecting to the quench heater is suspected to be broken. A. Siemko showed that a similar discharge was seen in the pre-series from one of the manufacturers where the heater stripped was teared. The problem was traced back to manufacturing procedures and corrected. The magnet currently affected is the number seven from this same manufacturer. The RB circuit should be locked together with spool pieces. Powering of RQD and RQF can be done. A task force will be organized immediately with M. Bajko, R. Denz, G. D'Angelo, R. Wolf and A. Siemko.
PGC tests for sector 5-6. C. Fernandez Robles
The two first phases of the PGC (powering of a group of circuits) tests were presented. This concerns global protection system, electromagnetic compatibility and current leads performance.
Two currents have been defined for these tests:
I_PGC_CYCLE: equivalent to 5 TeV for all circuits
I_PGC_ECM: 7000 A for RB, RQF/D and equivalent for the other circuits.
The powering will not be done using PLEP functions but the normal operation procedures. The maximum value for ramp and acceleration reached during commissioning should not be exceeded. It should be indicated in the procedures. R. Schmidt pointed out that the values should be the ones in the LSA database already used for commissioning.
During the global protection test all the main circuits (RB,RQF/D and IPQ) should go down without firing any quench heater.
In the ECM tests for the 600 A circuits, the current used should be commissioned current. The fast power abort on the correctors can be triggered via simulating a quench in the current leads or via PIC. This needs to be decided taking into account efficiency. Action: C. Fernandez Robles.
The slow power abort in the RQF circuit should generate a slow power abort in the RFD circuit and vice versa. This may not be ensured by the LSA software and it is not linked by hardware. It needs to be checked Action: A. Verweij
The PGC tests should take two days. The current and circuits undergoing slow and fast power abort for the PGC test in the matching section need to be defined. Action N. Catalan Lasheras, G. Kirby.
The final step described in the procedures is the current leads performance and heat run which includes the arc, matching section and the inner triplet.
A heat run of the circuits powered though resistive leads is scheduled, as they are not always powered at the maximum current. (After the meeting this was re-discussed and it was decided to operate these circuits at I_commissioned all along the PGC tests. The separated heat run can then be skipped).
Release for powering of the DFBs and stand-alone magnets in sector 7-8. J. Casas Cubillos
Two kind of checks are done to release the stand--alone magnets. The volumetric check to confirm the helium volume thought the boil-off tests was successfully done in all stand-alone magnets and is still pending for the D2-Q4 cryostat. The geometric check is done by overfilling and confirming the position of line D in the cold mass. This test gave an unexpected value for Q6L8.
Only Q5L8 and Q4L8 are released for powering.
In sector 8-1, the levels will be replaced by calibrated, supported levels as it was done in Q5R5.
The acceptance procedure and criteria for release of the stand-alone level measurements still needs to be written. Action N. . Catalan Lasheras and J. CasasOutcome of the analysis on high voltage breakdown of temperature sensor electronics. J. Casas Cubillos
In the electronic chain of the temperature sensors reading, some of the components are not qualified for voltages up to 1.9V as it should be tested during ElQA. One of the main problems are the connectors in the DFB auxiliary equipment which are qualified only for low voltages and are very sensible to humidity.
Besides, the electronic cards are often not capable to withstand 1.9 V even if they were required to do so. The problem is under investigation but could be due to residual acid left after cleaning.
A consolidation is proposed mainly consisting on cleaning the cards, changing the cables and the connectors. An ECR is being prepared but it will take 3-6 months to implement. All the investigations seem to indicate a manufacturing weakness but the panel recommends a review on the design of the card as part of the consolidation.
In the short term, reducing the testing voltage during ElQA should be considered. .
Result of the investigation in the orbit correctors faults. G. D'Angelo and R. Mompo
In the corrector circuit RCBV27.L6B2,a high value of magnet resistance was measured during PNO.a1. The problem was traced back to the value of the warm cable resistance stored in the database. The resistance was remeasured in short-circuit mode and updated in the database. The test PNO.a1 should now be repeated. A. Verweij pointed out that a similar error of opposite sign can mask the effect of a bad splice inside the magnet. G. D'Angelo explained that a resistive splice will also affect the flatness of the voltage during powering and this is also included on the acceptance criteria of the test.
The circuit RCBCV10.L6B1 passed successfully ElQA on 11 March. On April 14th, powering was not possible due to a PC fault. Further investigation in the tunnel revealed that the EE811 voltage tap was missing. When trying to perform reflectometry on this circuit the voltage tap was back again but with a high resistance. It is now impossible to locate the fault. It is proposed to power the circuit and then to pass 2 A through the voltage tap to confirm/compromise the continuity of the circuit.
Both circuits are released for powering
9 May 2008
N. Catalan Lasheras
General information
Commissioning of sector 5-6 is coming to a end. PGC tests are going on this week. Sector 7-8 is cold and the QPS individual system tests are starting. Sector 8-1 is also cold and about to start.R. Denz reported that the testing of interlocks and quench heaters in sector 7-8 has been successfully done for RQF and RQD circuits and is being performed for the L8 magnets. A problem has been detected in the B21L8 dipole where one of the four heater discharges shows an abnormal decay. Direct measurements from the IFS shows a high resistance of the quench heater. G. Kirby showed that a similar problem was seen last year in Q4.L8 where the wire connecting to the quench heater is suspected to be broken. A. Siemko showed that a similar discharge was seen in the pre-series from one of the manufacturers where the heater stripped was teared. The problem was traced back to manufacturing procedures and corrected. The magnet currently affected is the number seven from this same manufacturer. The RB circuit should be locked together with spool pieces. Powering of RQD and RQF can be done. A task force will be organized immediately with M. Bajko, R. Denz, G. D'Angelo, R. Wolf and A. Siemko.
PGC tests for sector 5-6. C. Fernandez Robles
The two first phases of the PGC (powering of a group of circuits) tests were presented. This concerns global protection system, electromagnetic compatibility and current leads performance.Two currents have been defined for these tests:
I_PGC_CYCLE: equivalent to 5 TeV for all circuits
I_PGC_ECM: 7000 A for RB, RQF/D and equivalent for the other circuits.
The powering will not be done using PLEP functions but the normal operation procedures. The maximum value for ramp and acceleration reached during commissioning should not be exceeded. It should be indicated in the procedures. R. Schmidt pointed out that the values should be the ones in the LSA database already used for commissioning.
During the global protection test all the main circuits (RB,RQF/D and IPQ) should go down without firing any quench heater.
In the ECM tests for the 600 A circuits, the current used should be commissioned current. The fast power abort on the correctors can be triggered via simulating a quench in the current leads or via PIC. This needs to be decided taking into account efficiency. Action: C. Fernandez Robles.
The slow power abort in the RQF circuit should generate a slow power abort in the RFD circuit and vice versa. This may not be ensured by the LSA software and it is not linked by hardware. It needs to be checked Action: A. Verweij
The PGC tests should take two days. The current and circuits undergoing slow and fast power abort for the PGC test in the matching section need to be defined. Action N. Catalan Lasheras, G. Kirby.
The final step described in the procedures is the current leads performance and heat run which includes the arc, matching section and the inner triplet.
A heat run of the circuits powered though resistive leads is scheduled, as they are not always powered at the maximum current. (After the meeting this was re-discussed and it was decided to operate these circuits at I_commissioned all along the PGC tests. The separated heat run can then be skipped).
Release for powering of the DFBs and stand-alone magnets in sector 7-8. J. Casas Cubillos
Two kind of checks are done to release the stand--alone magnets. The volumetric check to confirm the helium volume thought the boil-off tests was successfully done in all stand-alone magnets and is still pending for the D2-Q4 cryostat. The geometric check is done by overfilling and confirming the position of line D in the cold mass. This test gave an unexpected value for Q6L8.Only Q5L8 and Q4L8 are released for powering.
In sector 8-1, the levels will be replaced by calibrated, supported levels as it was done in Q5R5.
The acceptance procedure and criteria for release of the stand-alone level measurements still needs to be written. Action N. . Catalan Lasheras and J. Casas
Outcome of the analysis on high voltage breakdown of temperature sensor electronics. J. Casas Cubillos
In the electronic chain of the temperature sensors reading, some of the components are not qualified for voltages up to 1.9V as it should be tested during ElQA. One of the main problems are the connectors in the DFB auxiliary equipment which are qualified only for low voltages and are very sensible to humidity.Besides, the electronic cards are often not capable to withstand 1.9 V even if they were required to do so. The problem is under investigation but could be due to residual acid left after cleaning.
A consolidation is proposed mainly consisting on cleaning the cards, changing the cables and the connectors. An ECR is being prepared but it will take 3-6 months to implement. All the investigations seem to indicate a manufacturing weakness but the panel recommends a review on the design of the card as part of the consolidation.
In the short term, reducing the testing voltage during ElQA should be considered. .
Result of the investigation in the orbit correctors faults. G. D'Angelo and R. Mompo
In the corrector circuit RCBV27.L6B2,a high value of magnet resistance was measured during PNO.a1. The problem was traced back to the value of the warm cable resistance stored in the database. The resistance was remeasured in short-circuit mode and updated in the database. The test PNO.a1 should now be repeated. A. Verweij pointed out that a similar error of opposite sign can mask the effect of a bad splice inside the magnet. G. D'Angelo explained that a resistive splice will also affect the flatness of the voltage during powering and this is also included on the acceptance criteria of the test. The circuit RCBCV10.L6B1 passed successfully ElQA on 11 March. On April 14th, powering was not possible due to a PC fault. Further investigation in the tunnel revealed that the EE811 voltage tap was missing. When trying to perform reflectometry on this circuit the voltage tap was back again but with a high resistance. It is now impossible to locate the fault. It is proposed to power the circuit and then to pass 2 A through the voltage tap to confirm/compromise the continuity of the circuit.
Both circuits are released for powering
AOB
The following pending issues should be presented to the next MPP meeting:- Review of ramp rates by W. Venturini-Delsolaro
- Quench heater integrity by G. Kirby
- Testing plans for MCBC inside Q5L8 by R. Wolf
9 May 2008
N. Catalan Lasheras
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