Overview - LHC commissioning strategy with bean 2009

Overview - LHC commissioning strategy with beam 2009

The initial commissioning with beam in 2009 went well and a good sample of collisions at 450 GeV was provided to the experiments. The ramp to 1.18 TeV was commissioned and pilot collisions allowed the experiments to take some data at this energy.

Strategy

Go for collisions at top energy as soon as safely possible
Full Machine Protection commissioning will need a well adjusted and well understood machine
Perform phased qualification of machine protection using very safe and safe beams before increasing intensity.
Commission essential systems and measurements at 450 GeV
Move quickly into the snap-back and ramp
Hold full machine protection qualification until after first low intensity collisions
Respect safe beam limits during initial commissioning phase:

Energy	Safe beam	Very safe beam
450 GeV	1 e12	1 e11
1 TeV	2.5 e11	2.5 e10
3.5 TeV	3.1 e10	probe

The injector complex has defined the following beams:

LHCPROBE intensity range between 0.5-2E10 ppb and 1 bunch only. (<1 um/0.3 eVs)
LHCINDIV 2-12E10 ppb with 1-4 bunches (3.5 um/0.8 eVs)

Plan Outline

Establish circulating beams and initial 450 GeV commissioning ( Phase A.3 – fast track)
- Key instrumentation and measurements Tune, chromaticity, coupling, optics, orbit acquisition and correction
- RF capture and adjustment LDBS – phase 1
- Essential machine protection for 450 GeV+
  - LBDS, BLMs, BIS, collimators, experiments
Collisions at 450 GeV
- Solenoids/dipoles on (& then mostly off) - few shifts only
Ramp to low energy (~1 TeV) with safe beam
- appropriate machine protection established
- some protection from collimators in place
- LDBS > 450 GeV
- snapback, FiDeL predictions, etc.
- RF
- Q, Q’, orbit (10 Hz) measurements,
- aim for circulating beam at 1 TeV
- repeat until 2 beams@1TeV
Test collision procedure and possibly squeeze mechanics at 1 TeV
Test collisions at 1.1 TeV

Would hope to get this far before the 2009 Christmas stop

Commission Machine Protection appropriate for low intensity to 3.5 TeV:
- FMCMs, PIC, Collimators, TCDQ, BLMs, BPM interlocks, SMPs, RF frequency, LBDS…
Beam and system commissioning - ramp to 3.5 TeV
- beam dump, collimators, BLMs, RF…
- Tune, Q’, coupling, orbit…
Two low intensity beams at top energy - first collisions
Perform machine protection commissioning appropriate for increased intensity and squeeze commissioning.
Pilot physics

Time estimate

Phase	Time [days]	Bunches	Intensity	Main tasks
Circulating beam	4	1	2 e9	capture, energy matching, initial RF commissioning
450 GeV commissioning	4	1	5 e9	tune, Q’, C-, orbit, collimators, LBDS, instrumentation
450 GeV essential optics checks	2	1	5 e9	polarities, response, beating
450 GeV - two beams	1	1	5 e9	bumps, instrumentation
450 GeV - collisions	2	12	1 e10	experiments on at 450 GeV
Snapback and ramp to 1 TeV	4	1	2 e9	orbit, tune (PLL), chromaticity
Ramp to 3.5 TeV	2	1	5 e9	commission essential machine protection
3.5 TeV checks & bring on experiments' magnets	3	1	5 e9	solenoids, dipoles, experiment related machine protection
First collisions	1	1	5 e9 - 2 e10	safe beam at 3.5 TeV
	22

With optimistic machine availability - 1 month elapsed to establish first collisions at 3.5 TeV.

ML August 2009