LHC Programme Coordination Home Page

Configuration for the 2025 lead-lead run

Heavy Ion configuration and setup

Intensity ramp-up requested by MPP -- This is to be confirmed. Currently the website assumes the same requirements as in 2024.
- Intitial cycle performed with low intensity (filling schemes to be finalized).
  - 80b : 1 fill; 2h Stable Beams
  - 250b : 2 fills; more than 5h in Stable Beams
  - 450b : 2 fills; more than 5h in Stable Beams
  - Check list needed to be completed before going to higher number of bunches
  - 850b : 2 fills; more than 5h in Stable Beams
  - 1240b (full machine): corresponding to ~20 MJ of stored energy
- ALICE will perform a polarity change roughly half way through the run. After the polarity change, MPP requires one cycle with low intensity followed by one fill of 450b and more than 2h in Stable Beams .
The ion run is expected to be done with 50ns bunch spacing, with slip stacking injection configuration.


General beam properties
Beam energy	6.8 ZTeV
Max number of bunches per beam	1240	50ns bunch spacing
Ion beam intensity	2.3 x 10⁸	Assume same intensity as achieved in 2024.
Ion beam emittance	2.1-2.4 µm	Assumed same as 2024.
Luminosity leveling in IP1/2/5	6.4 x 10²⁷cm^-2s^-1	ALICE might level lower. Leveling to last around 1-2h (depending on beam and ALICE)
Luminosity leveling in IP8	1.5 x 10²⁷cm^-2s^-1	Maxumum value allowed from BFPP studies. Leveling to last around 2-4h.
IP1/5 (ATLAS/CMS)
β*	0.5m
Half crossing angle	150µrad	V (positive) in IP1, H (positive) in IP5
Virtual peak lumi estimate	10 x 10²⁷cm^-2s^-1	(approximate)
IP2 (ALICE)
β*	0.5m
External crossing angle	-/+ 150 µrad
Internal crossing angle	+/- 72 µrad
Total half crossing angle	+/- 78 µrad
Magnet polarity	Dipole polarity flipped at half way
Virtual peak lumi estimate	11 x 10²⁷cm^-2s^-1	(approximate)
IP8 (LHCb)
β*	1.0m	New for 2025 this is 1m rather than 1.5m.
Dipole polarity	negative	No change during the run
External half crossing angle	-210 µrad
Internal half crossing angle	+139 µrad
Half crossing angle	-71 µrad
Peak lumi estimate	1.5 x 10²⁷cm^-2s^-1	Leveled at this value (machine limit from BFPP).

The VdM scans need to be done in the 100ns configuration. They will be done with regular physics optics and using a physics filling scheme.

It is proposed to use the same filling schemes as were used in 2024 for the VdM fills.

Filling scheme optimised for IP2/8:

Filling scheme optimised for IP1/5:

Filling scheme equalized to all IPs (backup):

The following AGKs can be assumed: 33201

Validation fill, no SB required: Multi_21b_6_6_6_3bpi_9inj_PbPb_1us Download

Default filling schemes per intensity step, with 50ns slip-stacking and 56bpi, WITH INDIVs:

50ns Scheme, 56 bpi, 3 INDIVs	Download	Remarks
50ns_119b_58_51_58_56bpi_9inj_4NC_3INDIV_PbPb	Download	Ramp up 1st step : 2 hours SB, 3 INDIVs
50ns_291b_194_194_138_56bpi_9inj_3INDIVs_800ns_bs100ns	Download	Ramp up 2nd step : 2 fills with at least 5 hours SB with 3 INDIVs
50ns_451b_338_338_320_56bpi_11inj_3INDIVs_800ns_bs100ns	Download	Ramp up 3rd step : 2 fills with at least 5 hours SB, 3 INDIVs
50ns_795b_642_642_400_56bpi_18inj_3INDIVs_800ns_bs100ns	Download	Ramp up 4th step : 2 fills with at least 5 hours SB, 3 INDIVs

Default filling schemes per intensity step, with 50ns slip-stacking and 56bpi, NO INDIVs

50ns Scheme, 56 bpi, NO INDIVs	Download	Remarks
50ns_288b_192_192_136_56bpi_6inj_800ns_bs100ns	Download	Ramp up 2nd step : 2 fills with at least 5 hours SB with NO INDIVs
50ns_448b_336_336_318_56bpi_8inj_800ns_bs100ns	Download	Ramp up 3rd step : 2 fills with at least 5 hours SB, NO INDIVs
50ns_792b_640_640_398_56bpi_15inj_800ns_bs100ns	Download	Ramp up 4th step : 2 fills with at least 5 hours SB, NO INDIVs

Default filling schemes at full machine, with 50ns slip-stacking and 56bpi, NO INDIVs

50ns Scheme, 56 bpi, NO INDIVs	Download	Remarks
50ns_1240b_1032_1032_557_56bpi_PbPb	Download	Full machine with 50ns bunch spacing, default filling scheme, same as 2024.

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