LHC progressThursday 30th April 2015

Coordination: Mike Lamont, Wolfgang Hofle

Plan Wednesday 29th April

• Interlock BPMs in IR6, set-up & validation of intensity range and with bumps

• RF Long. Blow-up Commissioning (smooth algorithm)• ULO steering • ULO scan at 450 GeV with cold beam screen• Loss maps and collimation checks at 450 GeV

• Ramp with 2 probes / per beam, loss maps at 6.5 TeV, MUFO check

• Ramp with 1 nominal per beam• Revisit interlocked BPMs

Timeline (1)

• 7:00 Intensity scraping tests for Interlock BPMs in IR6• 9:34 cryo starts cooling down BS in 15R8• 9:40 SPS MPS tripped (door)• 9:56 SPS MPS tripped again (cooling BA1)• 11:12 setting-up of bump for ULO• 12:11 de-bunching beam 2• 13:38 Long. Blow-up Commissioning starts• 13:38 cryo informs that beam screen is at nominal temperature• 14:10 cryo maintain lost during tests in R6• 15:13 cryo turbine point 8 lost & saved (4x during

afternoon/night), 2x transparent, piquet changed cable at 4th time

Timeline (2) • 17:24 Quench of RQ4.R5 due to bad temperature regulation• 20:59 Pre-cycle started• 21:55 Beam back• 23:02 Collimation loss maps with ADT• 23:36 cryo point 8, turbines• 00:42 start of partial ULO Scan • 01:37 SIS interlock dumped (triplet motors in point 5)• 01:40 cryo lost in point 8, ML8 (piquet called to change cable) • 04:52 pre-cycle MSL8• 06:00 beam back • 06:15 Injection handshake with experiments (dip)• 06:41 mismatch of functions in prepare for ramp (Fidel)

Cardiogram last 24 hnot necessarily tracking the faults that stop beam

SPS MPS

cryo turbine point 8cryo RQ4.R5dip

all IPQs pre-cycled

BPMSX/I Tests

Summary of intensity scrapping tests of interlocked BPMSX/I channels: • B1 and B2 interlock channels in high sensitivity

mode trigger the interlock system at intensities 1.5e9 p/bunch.

• High sensitivity works perfectly with nominal bunches on these channels.

• In low sensitivity, limits for B1 and B2 BPMSX/I trigger the interlock system at 1.5e10 p/bunch.

BE-BI

Interlock BPM – Scraping both one pilot and one nominal to measure the dynamic

range of the high and low sensitivity ranges of BPMint– High sensitivity: Beam dumped at 1.5E9, can handle the nominal

bunch intensities: Need higher bunch intensity to check where is the upper limit of our dynamic range

– Low sensitivity: Beam dumped at 1.5E10 - work up to max bunch intensity (2-3E11)

– Testing Beam dump functionalities changing the interlok threshold (bunch counts over 10 and 100 turns) : worked fine

– Issue found on BPMint2 crate while doing MPP test with orbit bumps:• suspected an hardware issue in VME crate - under investigation

– Need to redo the MPP tests as soon as the problem is solved : Keep the BPM interlock masked so far - update later today

BE-BI

Intensity Scraping

Long blow-up

Summary of tests longitudinal blow-up:

• Test at 450 GeV finished. The new algorithm pre-distorts the excitation spectrum so that the core of the bunch is hit harder than the tails. Works fine at 450 GeV. We leave it on for next ramp (with pilots).

• If it fails:• Longitudinal blow-up is not necessary to ramp probe do not

arm it • BUT the nominal intensity bunch CANNOT be ramped without

longitudinal blow-up. It will be unstable sometime in ramp.

H. Timko, M. Jaussi, P. Baudrenghien

Longitudinal display

clean injection, loops and longitudinal injection error OK

Bunch length

H. Timko, M. Jaussi, P. Baudrenghien

Loss maps at 450 GeV

• We performed a first complete set of loss maps with injection protection devices OUT (as TDI's are not yet aligned) for both beams, comparing the results obtained by using nominal and beam-based beam sizes. This includes off-momentum loss maps. For both types of settings (beam-based vs nominal sizes) the betatron loss maps look good. We will decide which settings have to be used after detailed off-line analysis.

• Off-momentum loss maps showed that for beam 2 the nominal beams sizes should be used because the beam-based ones have a problem for the TCP. The alignment of this collimator should be re-checked.

• From the cleaning point of view, the new settings are ok for the injection of up to tens of nominal bunches!

S. Redaelli & team

ULO bump• The beam reference orbit is now bumped by +1mm in V and -3mm in H at

the location 15R8. It is 'invisible' as long as one compares to the reference orbit.

• The bump has been added as a knob (--> in ramp, squeeze...) such that it can be adjusted easily. It also appears on the reference orbits as overlay bump.

J. Wenninger

Aperture scan (partial) @15R8

For experts to look at

• Cryo point 8, PLC cable fixed by Piquet• SIS dumps, lost communication (2x), once causing beam dump• RF loops at injection (2x), occurred once on beam 2, and once on beam 1

(22:34): de-bunching with 1 pilot and 1 nominal (Philippe B.)• Incorporation at start of ramp (Fidel, OP procedure)• ADT injection oscillation display (ADT team)• chirp checks for BBQ (BI)• Interlocks in ramp (RF, A. Butterworth)• Handshake via dip not working for some experiments, OP requested

handshake in wrong beam mode• Interlock BPM, to be re-visited today

RF loops ok ?

22:34, de-bunching of beam 1, ok after re-injection with probe of 7x109 protons