1. LHC 15 April 2015 7:19: UFO event detected by on BLM 15.R8 and beam dump 8:46: P2 cold compressor trip and recovery during morning shift. Access given –Vacuum –BPM –BLM –AC dipole –BWS –cryogenics –ABT 16:22: Machine cycling and preparing for beam. 18:18: Beams in. 16/04/2015LHC Morning meeting – MG & JU1

2. LHC 15 April 2015 First activities: check outcome of intervention during accesses –BPMs: several successful fixes, but still some to do at the next access. –BWS Beam 1: PM hold HV. Intervention successful (Emiliano, Guillaume). –OFB: The instability observed in the OFB has been traced to an incorrect parsing of optics data…(Stephen, Diogo, Jorg, Kajetan, Laurette, Letizia). –BLMs: UFO buster is showing data with the new BLM. 15R8.B2E22 showing large values, 15R8B2E21 installed towards Q15 not showing anything yet (Jan, Bernd). –IST on the 2 Injection BICs: successfully completed. 16/04/2015LHC Morning meeting – MG & JU2

3. LHC 15 April 2015 21:35: ADT setting up session finished 22:07: Longitudinal blow up in the ramp (Philippe, Helga, Michael, Giulia). Target 1.25 ns. Left in for subsequent ramps, but –ramp the target value from 1ns to 1.25 ns in the first 300 s –reduce gain by 2 (same reduction through the ramp). 16/04/2015LHC Morning meeting – MG & JU3

4. LHC 16 April 2015 00:03: Beams dumped: same location and after the same time at flat top as the morning dump. –Confirmation that the mobile BLM closer to Q15R8.B2 sees no signal –Confirmation that the source is deep in the dipole and not in the interconnect. FLUKA simulations on-going (Anton et al.) Longitudinal blow up has not changed the features of the phenomenon 16/04/2015LHC Morning meeting – MG & JU4 New mobile BLM

5. LHC 16 April 2015 2:56: Beam 1 at flat top: optics measurements performed. –RCO.A45B1 quenched at flattop. 6:59: Beam 1 still in. Confirmation that the issue at top energy is truly Beam 2 related. 16/04/2015LHC Morning meeting – MG & JU5 Longitudinal blow up still rather violent

6. LHC 16 April 2015 First optics measurements at 6.5 TeV: beta-beating 16/04/2015LHC Morning meeting – MG & JU6 Comparison with 2012 situation: but optics is different in IR4!

7. LHC 16 April 2015 First optics measurements at 6.5 TeV: normalised dispersion 16/04/2015LHC Morning meeting – MG & JU7 Comparison with 2012 situation: but optics is different in IR4!

8. Programme of the day(s) Access from 9am. Some activities –ATLAS X-rays –BIS checks: additional checks on the 2 Extraction BICs –BPMs Preparation for nominal bunch intensity at injection –Reference orbit –Collimators –Injection protection MUFO studies –Observations at injection: more bunches, one nominal bunch –Orbit scans in the region 15R8.B2 16/04/2015LHC Morning meeting – MG & JU8