Minutes of Meeting 12 October 2012

The meeting started with a review of the previous minutes of the last meeting by KP.

Minimum time between PS ejection

GB presented a short study. The converters of line F16 from slot QFO105 to slot BHZ377 were considered. The following columns are included as in attached table:

• power supply minimum nominal current
• power supply maximum nominal current
• minimum measured magnet current
• maximum measured magnet current
• minimum magnet current setting allowed
• maximum magnet current setting allowed
• minimum current as required; according to beam energy measured at 1555G (beam energy measurement)
• maximum current as required; according to beam energy measured at 12566G (beam energy measurement)
• maximum operating current as imposed by LHC cycles (26GeV).
• rq (special requirements (user/beam type))

The conclusions of this study:

• during the 1.2sec basic period operation the main limitation comes from a CNGS (14GeV/c beam extraction at 835ms) period followed by a ToF perod (20GeV/c beam extraction at 695ms). The time available for the converters to prepare the magnets for the new energy is only 1060ms
• during the 0.9sec basic period the CNGS extraction would take place at 770ms instead of 835ms. This reduces the time between extractions to: 900ms-770ms+695ms=825ms for the same user sequence.

The 1060ms and 825ms are therefore the minimum times between extractions at 1200ms and 900ms basic periods respectively. These are for the CNGS to ToF transition.

Field measurement in critical circuits.

GB inquired about the progress in the discussions for magnet field measurements.

KP Dominique Bodart is aware and asked for some time to discuss internally about this.

SG mentioned that this is an important aspect because certain measurements require this facility. Right now current measurement only gives an indirect feeling for the beam.

GLG mentioned that from the converters point of view and to unify the control approach if field measurement is implemented it would be good to do this in all circuits.

Going to low current during long periods of line inactivity

KP In previous meetings there were discussions about the posibility to ramp down the current in case the line is not being used for long time. This would allow saving power and perhaps extending the life of equipment.

GM is this still something we are interested in?

GLG yes this is still in the agenda. We will try to include it especially if the degaussing cycle can be scrapped by measuring field.

End of the meeting 11:15

-- KonstantinosPapastergiou - 12-Oct-2012