LHC 18 & 19 April 2015 At 450 GeV with bumps, no increased MUFO activity. Beam screen 15R8 warming up to 80 K, ongoing for the day 09:00: Orbit studies with K-modulation IP1/2/8/5 at injection 12:00: End of long fills at injection for MUFO hunting 14:00: Beam dump aperture studies, TCDI and TDI tightening 00:00: V-bumps 15R8 at injection 01:30: Ramps to 6.5 TeV 04:00: Beam at flat top, orbit changes 15R8, 08:00 dump due to cryogenics Linac problem, no beam for a while 19/04/2015LHC Morning meeting – MG & JU1

Orbit Work by Jörg 19/04/2015LHC Morning meeting – MG & JU2 Remaining ‘bad’ BPMs

Beam Dump Aperture & co. All injection protection collimators (not TCLIA and TCLIB) are at +/- 10 sigma and with all the thresholds properly set up. We could inject with the interlocks unmasked. 19/04/2015LHC Morning meeting – MG & JU3 Wolfgang, Chiara, Francesco, Jose

Conclusions from beam dump studies Measured circulating apertures (circulating beam with bumps) in IP6 –Should find 15 mm for the TCDS from mechanical centre, start losing at around 10 mm for both beams, the beam size was difficult to estimate (see TDI alignment where we found large beams) Measured extraction apertures (phase scan) –aperture slightly tighter and quite off-centre at TCDS for B2 (phase 0), otherwise OK Tested beam extraction for 14/15 MKD (simulation of kicker erratic), see plot, plot descriptions to be edited for B1/B2, can distinguish in filename - have at least +/- 2 MKDs of aperture --> OK 19/04/2015LHC Morning meeting – MG & JU4 Wolfgang, Chiara, Francesco, Jose

15R8 Beam Screen Temperature 19/04/2015LHC Morning meeting – MG & JU5 80 K we were aiming for Beam screen entry temp. Beam screen temp

O-night Applied vertical bumps at 6.5 TeV at 15R8 –Significant losses…. Also higher beam screen temperature to «unfreeze air…» Did this cause the difference? 19/04/2015LHC Morning meeting – MG & JU6 Beam stayed in for 4 hours, dumped due to control problem of cryogenics

Next Recover –Linac 2 HV cable (this can take a while) –Cryogenics control One nominal bunch (about 7e10 p+) at injection –Assuming Machine Protection main outstanding items checked and agreed –Needs RF capture set-up Useful for –MUFO understanding –Rerence orbit –Collimation set-up etc. Transverse feedback 19/04/2015LHC Morning meeting – MG & JU7