LB

OC

– 3

0 M

arch

201

1

LHC

INJECTION STATUS – TOWARDS 144 BUNCHES

1

W. Bartmann, C. Bracco, L. Norderhaug-Drosdal, B. Goddard, W. Hofle, D. Jacquet, V. Kain, M. Meddahi, J. Uythoven, D. Valuch, J. Wenninger

LB

OC

– 3

0 M

arch

201

1

LHC

Injection Quality Statuso 24 bunch injection clean:

− Loss maxima from uncaptured beam

− TCDI loss maxima: fill 1646 – 200 bunches filling, 24 bunches per inj

beam 2 3 % maximum, beam 1 8 % maximum

− Beam 1 trajectory not perfect in H, pointing to HiRadMat switch magnet

2TCDIs

LB

OC

– 3

0 M

arch

201

1

LHC

Fine tuning of some thresholds required

o From time to time: low losses “seem” high

o BLMQI.06L2.B2I20 threshold too low

3

Threshold of BLMQI.06L2.B2I20

LB

OC

– 3

0 M

arch

201

1

LHC

Transverse losses - observationso Scraping in the SPS needs to be well under control and switched on

− SIS surveillance will come

o Correcting back to reference trajectory works well

− Still more statistics needed for consistency between pilot and nominal intensity corrections

− Need to be able to compare steering settings for 2 users and task in nominal sequence for copy

− Then steering to be done by OP

o For the time being no issues for increasing intensity from transverse losses

4

Beam 2:8 bunch injection, no scraping on

LB

OC

– 3

0 M

arch

201

1

LHC

Longitudinal Losseso Larger capture voltage seems to pay off:

− But also some filters changed (e.g. TCTVb)

− Losses at the end of filling: 200 bunch fillings

− …need to check losses on TCLIA/TCTH for beam 1 – losses on D2 on other side are higher than on triplet

o More analysis needs to be done. If possible would like to re-calibrate

5

Fill Nr Beam 1 [%] Beam 2 [%]

1645 5 10

1646 10 16

1647 6 8

Max loss in percentage from dump thershold downstream of TDI

LB

OC

– 3

0 M

arch

201

1

LHC

Abort Gap Cleaning @ InjectionAvailable now:

o Sub-Sequence to move abort gap cleaning to injection settings

o Sub-sequence to stop and start abort gap cleaning:

− start abort gap cleaning in prepare for filling sequence

− …and stop before starting the ramp (tune feedback)

o Status:

− Tested with beam: first bucket, NOT with last possible bucket

− Sub-sequences are not part of nominal sequence yet

− MCS checks need to be re-enabled and tested

6

LB

OC

– 3

0 M

arch

201

1

LHC

Injection Cleaning – not tested with beam

o Injection Cleaning – modus operandi:

− Injection sequencer requests next injection + configures and switches on cleaning

− No injection event: injection cleaning switched off with injection sequencer time-out or internal time-out of injection cleaner

− If injection arriving: automatic switch off cleaning

injection forewarning – details still to be discussed

With beam-in

− At the end of filling: cleaning amplitude and excitation mode set to zero through sequence

o Sequences: prepared, not in nominal sequence Sub-sequence to prepare cleaning before filling

Sub-sequence to disable cleaning after filling

7

LB

OC

– 3

0 M

arch

201

1

LHC

Injection Cleaning in Injection Sequencer

o Implemented as part of the injection sequencing

8

LB

OC

– 3

0 M

arch

201

1

LHC

Towards 144 bunch injectionso Quantify effect of TI8 shielding installed during TS (1 hour)o Check aperture TI2 and TI8 after vacuum intervention Shutdown – needed before

injection of >24b (0.5 shift)

o 75 ns spacing, up to 96 bunches (0.5 – 1.5 shifts)− Check losses in the line, oscillations, scraping SPS

− Re-steer if necessary, re-optimise collimators if needed (unlikely...)

o 50 ns spacing, up to 144 bunches (1 – 3 shifts)− Start with 12b

− Check losses in the line, oscillations, scraping SPS

− Re-steer if necessary, hope not to have to re-optimise collimators (can open to +/-5 sig if needed)

− Increase intensity injected in steps (36, 72, 108, 144)

− Checks in SPS extraction, TLs and in LHC at each step (losses, trajectories, oscillations, damping, capture, cleaning, vacuum, ...)

o 25 ns only after experience− Have to obtain more operational experience with up to 144 bunches before increasing

the injected intensity

− Including experience with abort gap and injection gap cleaning

9

LB

OC

– 3

0 M

arch

201

1

LHC

10

LB

OC

– 3

0 M

arch

201

1

LHC

Beam 2 – 24 bunches

11