Overview - LHC commissioning strategy with bean 2009

Overview - LHC commissioning strategy with beam 2010

Update May 2010

The squeeze to 2 m. in all experiments' interaction points has been commissioned and stable beams at the safe beam limit is now more-or-less routine.

The next month or so will be spent fully qualifying the machine setup and procedures for higher intensities. The first two planned increases in intensities are to a total single beam intensity of a round 1 e11 and then double this - this should take a month or so. The total single beam energy will then be around 100 kJ. Any further increase will demand that we really have the machine protection system. collimation, beam dump system and operational procedures fully nailed down.

Strategy

Respect safe beam limits during initial commissioning phase - perform phased qualification of machine protection using very safe and safe beams before increasing intensity.
Re-commission essential systems and make necessary measurements at 450 GeV
Commission ramp to 3.5 TeV
Pilot collisions at 3.5 TeV unsqueezed
Commission squeeze to stage A target values
Establish "stable beams" at target squeeze values with beam intensity below Safe Beam Limit.
Full Machine Protection commissioning will need a well adjusted and well understood machine - hold full machine protection qualification until after first low intensity collisions

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

Detailed planning is a deliverable of the LHC beam commissioning workshop

Plan Outline

Re-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 adjustment
- LDBS checks
- Check essential machine protection for 450 GeV+
  - LBDS, BLMs, BIS, collimators, experiments
Commission Machine Protection appropriate for low intensity to 3.5 TeV:
- FMCMs, PIC, Collimators, TCDQ, BLMs, BPM interlocks, SMPs, RF frequency, LBDS
Ramp to 3.5 TeVwith safe beam
- appropriate machine protection established
- collimators at intermediate
- LDBS > 450 GeV, dumps in ramp
- snapback, FiDeL predictions, etc.
- RF
- Q, Q’, orbit measurements,
- bring 2 beam to 3.5TeV - separation bumps on
3.5 TeV measurement program: optics, tune, Q', beating, dispersion, aperture checks
Test collison procedure - pilot collisions at 3.5 TeV
Commission squeeze and associated machine protection (noteably collimation)
Stable beams at target squeeze values with safe beam intensities
Perform machine protection commissioning appropriate for increased intensity.
Pilot physics

Time estimate

Phase	Time [days]	Bunches	Intensity	Main tasks
Circulating beam	2	1	2 e9	essential checks, orbit, RF etc.
450 GeV recommissioning	7	1	5 e9	tune, Q’, C-, orbit, collimators, LBDS, instrumentation
450 GeV essential optics checks	3	1	5 e9	beating, energy matching
450 GeV - two beams	1	1	5 e9	bumps as standard set-up, adjust TDI etc
Ramp to 3.5 TeV	5	1	5 e9	commission essential machine protection, experiments' dipoles on in ramp, orbit and tune feedback
3.5 TeV measurements & MPS	7	1	5 e9	standard measurements plus machine protection checks etc.
Pilot collisions unsqueezed	3 - 5	2	5 e9 - 3 e10	safe beam at 3.5 TeV
Commission squeeze	4	2	5 e9	orbit and tune feedback, collimation, aperture, bumps, machine protection checks, beam dumps etc.
Pilot collisions squeezed - stable beams	7	2	5 e9 - 3 e10	safe beam

With optimistic machine availability. Note agreement to provide stable beams for collisions - this takes a long, careful time to set up.

ML January 2010