CERN

Configurations for Special Runs / VdM in 2026 (under constructions: for now the same as 2025 vdM!!!)

LPC home

LPC: 79977

 

This page reflects the planned program in 2025. The times for scans are not updated after data-taking but some are based on previous years as indicated. In case of doubts do not hesitate to contact the LPC (or in case inconsistencies/mistakes are spotted).

 

van der Meer scan program

Step Duration Experiments activities Remarks
Scans IP2/8 - VdM optics

~10h
(plus overhead)

 
ATLAS CMS LHCb ALICE
0h15: DOROS Gain scan
head-on head-on 1h50 : LHCb part 1 (SMOG-less + VELO fully closed) no automatic leveling during scans
1h40 : LHCb part 2 (SMOG-less + VELO open)
2h40 : LHCb part 3 (SMOG + VELO open + LSC)
ghost-charge 1h30 : ALICE part 1 (scan)
1h30 : ALICE part 2 (LSC)
1h00 : ALICE part 3 (scan with offset)
0h15: DOROS Gain scan

 

Filling Scheme:
Multi_74b_63_34_29_4bpi_23inj_1000ns_bs1000ns
Download

Scans should ideally happen in the same fill. If beams are dumped during a scan will need to repeat at least that full part

LHCb VELO Ghost charge measurements throughout ALICE scan, if possible.

Estimated times.

LSCS and Scans IP1/5 - VdM optics (50m at IP8)

~24h
(plus overhead)

 
ATLAS CMS LHCb ALICE
4h00 : LSC head-on head-on, SMOG on ZDC in, +/+, no automatic leveling during the scans
head-on 4h00 : LSC
8h00 : vdM   ghost-charge
head-on 8h00 : vdM

 

Filling Scheme:
525ns_146b_144_35_20_8bpi_21inj_800ns_bs525ns
Download

LSC and scans should ideally happen in the same fill. If beams are dump during a scan will need to repeat at least that full part

LHCb VELO Ghost charge measurements during the vdM scans, if possible.

Times have been revisited for 2026.


 

van-der Meer scan parameters (copied from 2024 page)

Beam parameters for Calibration Transfer fill

Items Remarks
Filling Scheme 525ns_140b_140_75_16_8bpi_19inj_800ns_bs525ns
Download
Bunch Spacing 525 ns (minimal)
Injections up to 2 batches of 4 bunches
Emittance in Stable Beams as during physics fills
Intensity in Stable Beams around 1.4x1011 ppb
Brightness (bunch intensity / emittance) as during physics fills

 

Beam parameters for scans in IP1 and IP5

Items Remarks
Filling Scheme 525ns_146b_144_35_20_8bpi_21inj_800ns_bs525ns
Download
Bunch Spacing 525 ns (minimal)
Injections up to 2 batches of 4 bunches
Emittance in Stable Beams 3µm -- tolerable variations: 2.5µm to 3.5µm; some spread O(20%-30%) is welcome
Intensity in Stable Beams 0.8x1011 ppb  --  tolerable variations: 0.7x1011 ppb to 0.9x1011 ppb;  some spread O(20%-30%) is welcome
Profiles Preparation for VdM : Gaussian profiles which factorise the beam wrt H and V planes
Injection Optics With crossing angle to not have problems with LR interactions when beams are large at injection

 

Beam parameters for Scans in IP2 and IP8 (optics applies to also scans in IP1/5)

Items Remarks
Filling Scheme Multi_74b_63_34_29_4bpi_23inj_1000ns_bs1000ns
Download
Bunch Spacing 1000 ns (minimal)
Injections up to 4 batches of 1 bunch ("traditional" VdM schemes)
Emittance in Stable Beams 3µm for LHCb;  >3µm for ALICE (second in scan programme)
Intensity in Stable Beams 0.7x1011  - 0.9x1011 ppb in LHCb
0.4x1011  - 0.9x1011 ppb in ALICE (ALICE is second in the scan programme)
Profiles Preparation for VdM : Gaussian profiles which factorise the beam wrt H and V planes
IP8 beta* 24m in IP2/8 scan, 50m in IP1/5 scan
IP8 Dipole polarity Down, +
IP8 external half crossing angle  -300 µrad; internal half crossing angle : -138 µrad --> effective half crossing angle at IP: -438 µrad.
IP2 beta* 19m
IP2 polarities + / + (Dipole and L3 magnet)
IP2 internal crossing angle -72µrad
IP2 external crossing angle 145 µrad
IP2 effective crossing angle +73µrad which is ok for using the ZDC
IP2 special request BRANs retracted
Injection Optics With crossing angle to not have problems with LR interactions when beams are large at injection

This web site is owned by the account lpc .