LBDS commissioning – MKD tests

Viliam Senaj, 11/12/2013

MKD/B2 tests• HV tests (up to 5 TeV) without major problems:

– noisy Trigout on Gen. H (up to 5V noise signal) – replaced chassis with PTU&PTC

– Noisy output on one PTU of Gen. D – replaced PTU– Triax cable connectors on Gen. B – difficult to insert – replaced cables– Triax cable and 3 kV HV PS cable not fully inserted on Gen. E (27/11)

• No abnormal sparking activity observed - surveillance of retriggering pick-ups Cts2a&b – with the same settings for all generators

• DC 7TeV test: erratics on B (3 erratics 2 GTOs broken), D (6 erratics no damage), G (1 erratic no damage), J (3 erratics 2 GTO broken), N (2 erratics no damage)

• 48 hours ramp test: 10min 400 GeV; 10 min ramp to Emax; 90 min at Emax and (12h 6.5 TeV, 12h 6.75 TeV, 24h 7 TeV) - OK (without B&J)

Spontaneous firing of MKD/B2

Spontaneous firing of MKD/B2

Spontaneous firing of D/B2 on 16/11 02:13:06

Spontaneous firing of D/B2 on 16/11 02:13:06

Spontaneous firing (?) of B/B2 on16/11 20:41:10

Spontaneous firing of B/B2 on16/11 20:41:10

Spontaneous (?) firing B/B2 during switching off D/B2 18/11

Erratic of B/B2 during switching off D/B2

Non typical self-firing (?) of G/B2

Searching reasons of spontaneous firing

• Abnormally dry air observed in UA67 during tests (dew point - 9 deg)• To find if it affects B1 – it was put in DC mode between 30/11-03/12: ~24h

rising from 6 to 7 Tev; 36 h at 7 TeV and finally 24 h at 7.1 TeV; no self-firing observed

Searching reasons of spontaneous firing

• Hypothesis of charging of plexiglass insulation rods by friction of dry air blown by ventilators towards GTO stacks: switched off ventilators in Gen D, E, F, G, H, I, J – during 7 days – not confirmed

• Observation of noisy output of several PTU – even PTU signal before GTO current – on Gen. D:

Continuation tests• Generators B and J in laboratory for tests• DC test during Christmass• DC and ramp test in 2014• Surveillance of PTU activity/retrigger propagation (thresholding)