LHC 9 & 10 May 2015• 7:50: Start ramp for de-squeeze optics measurements• 10:15: Measured squeezed optics• 12:00: Dump • 13:00: Start local aperture measurements at the IPs• 18:15: Beam used, no new beam from CPS since about 13:00….

– PS RF followed by PS POPS

• 19:45: Start pre-cycle RB.A67 tripped at 230A, QPS problem due to redundant UPS missing

• 21:00: Access in Point 6• 22:45: …..and cryo lost S12 due to water fault, water pumping station

of BA6 is down…..• 23:30: QPS problem solved but cryo not in good state…• Present estimate for beam back is 16:00 to be followed by pre-cycle

LHC Morning meeting – ML & JU 110/5/2015

De-Squeeze: Smooth• Played the full de-squeeze to collisions: • Ran the tune change QCHANGE BP to move to collision tunes• Ran the de-squeeze in one step with collision tunes• Ran the BP to adapt the crossing angles

– IR5 from 145 to 0, IR8 from 230 to 320 microrad• Ran the collision BP (all separations off)• Measured optics• When the optics is corrected (if needed) the sequence is ready for

nominal bunches and setup of collisions (and TCTs)

10/5/2015 LHC Morning meeting – ML & JU 2

LP, RoSu, JW

Losses 8R8• Warning level (42%) on BLMBI.08R8.B0T10_MBA-MBB on 40 us

RS just before launching the de-squeeze around 8:48 • Close to our ULO at 8R16• Similar losses at other moments…..

10/5/2015 LHC Morning meeting – ML & JU 3

Local Aperture Measurements• IR1:

– First losses observed on MQX with half crossing -430urad (due to B2). However, this step must be repeated because not clear losses were observed

– First losses observed on MQX with half crossing 500urad. Clear losses observed on C3R1 due to B2.

– Regarding the separation plane, losses were observed with bumps of -400urad and +320urad.

• IR 2 only separation plane B1 due to limited beam availability– Regarding the separation plane, losses were observed with bumps of -490urad and

+320urad.

• IR5: – Regarding the separation plane, losses were observed with bumps of +340urad.

DM, PH, GV + OP crew

10/5/2015 LHC Morning meeting – ML & JU 4

The Plan

• Recover from water cooling fault leading to cryogenics problem. Turbines not going properly yet, pressure gauge to be replaced to recover full power

• Pre-cycle• Once recovered, options to be confirmed:

– Optics measurements / Ramp nominal / TCDI / …

10/5/2015 LHC Morning meeting – ML & JU 5