MKD dust related actions

Viliam SenajTechnical Coordination Meeting

27/01/2015

• Erratic of 2nd family on MKD A/B2 on 18/01 at 6.5 TeV• Presence of some amount of dust inside generators MKD confirmed (B1:

B+N; B2: A+B+N+O)• Cleaning – delicate • Incorrect cleaning - worse• Done during WE 23 -25/01/2015:

– Conditioning up to 6.8 TeV – OK– 1 ES up to 7.1 TeV – OK

• Plan:– 7 days @ 6.8 TeV (cycle test)– If problem again on A/B2 – replacement– If problem on more generators – cleaning of all of them– Otherwise waiting with cleaning till confirmation of possibility to cover the

perforation (overheating?) to obtain “dust proof MKD rack”

Cleaning strategy

Dust proofing the MKD• Reliability run in 2008 – with side panels non-perforated• Perforated panels installed at the beginning of 2009 (cooling reason?) • Temperature stabilisation (Peltier module) added to the GTO stack

compartment during the same period• Self triggering started in July 2009• To avoid dust penetration – blinding of perforation• Test of temperature rise inside “Main capacitor compartment” with

perforation blinded – ongoing in 867• Certain temperature rise expected with some influence to a pulse

current value: main capacitor temperature dependence ~ - 300 ppm/K; +10 deg ~ - 0.15 % of Imax1

• Temperature rise so far observed (after 3h at 2 TeV) ~ + 3 deg ~- 0.05 % on Imax1 (in reality no visible change of magnet current)