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Configurations for Special Runs / VdM in 2022 |
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The parameters on this page reflect the best current knowledge and will be regularly updated and changed accordingly. Please consider this when using these parameters for any estimate. In case of doubts do not hesitate to ask the LPC.
It remains to be determined if a different AGK setting will be needed for the vdM and LHCf run (likely not).
The following is largely based on 2018 procedures and expected to evolve in future discussions.
The VdM programme is scheduled to start after the 3b validation fill and vdM cycle validation after TS1 and will be interleaved with the LHCf low-µ run. This will probably fall on the weekend of the 17/9/2022 with . The programme consists of the following steps (no turn-around times taken into account here).
Maximum separation allowed by MPP: 2.5 nominal σ for each beam in one plane at a time. Separation in both planes at the same time are not allowed. The limits are given in terms of nominal emittance : εn=3.5µm. This means that the de-facto separation is larger since we in fact run with lower emittance (~2.3µm - to be updated).
Step | Duration | Experiments activities | Remarks | ||||||||||||||||||
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3b validation fill - low ß* optics | 30min |
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30min Stable Beams for MPP
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Non-linearity measurement fill (3b - vdM optics) | 2h |
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Filling Scheme: 1-3 non-colliding nominals in each beam. No long-range anywhere Could potentially be done during final vdM cycle validation TBD if CMS would like to do the same type of scan |
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Calibration transfer fill (140b - low ß* optics) | 4.5h |
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Filling Scheme: Multi_525ns_140b_140_75_16_8bpi_19inj.csv Scheme optimised for few AGK changes (might change for 2022) No ß* levelling (stay at 60cm) |
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LHCf run (vdM optics) | 2-4 days |
See details below
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Filling Scheme: Multi_525ns_152_150_0_0_8bpi_19inj.csv |
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LHCf removal | 8 hours |
Access to tunnel to extract LHCf detectors
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Scans IP2/8 |
8h45min |
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Filling Scheme: |
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Scans IP1/5 |
15h45min |
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Filling Scheme: ATLAS 1 2 and 3 4 need to be in same fill CMS: 1 and 2 need to be in same fill |
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600b - ramp up fill | 5h |
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Filling Scheme: 25ns_603b_590_524_542_48bpi_17inj More special runs here? |
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Normal physics fill | optimal |
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Filling Scheme: Default 2022 full ring - TBA To be seen if additional intermediate fill needed as part of ramp-up |
Items | Remarks |
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Filling Scheme | Multi_525ns_140b_140_75_16_8bpi_19inj.csv |
Bunch Spacing | 525 ns (minimal) |
Injections | up to 2 batches of 4 bunches |
Emittance in Stable Beams | tolerable variations: 2µm to 3µm |
Intensity in Stable Beams | 1.2x1011 ppb -- tolerable variations: 1.1x1011 ppb to 1.25x1011 ppb; |
Brightness (bunch intensity / emittance) | < 0.5 x 1011 ppb / µm |
Items | Remarks |
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Filling Scheme | Multi_70b_58_20_22_4bpi_19inj.csv |
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 |
IP 8 Dipole polarity | + / + |
IP 8 external half crossing angle | 145 µrad; internal half crossing angle : -75 µrad --> effective half crossing angle at IP: 70 µrad which is ok for using the ZDC. |
Injection Optics | With crossing angle to not have problems with LR interactions when beams are large at injection |
IP2 polarities | + / + (Dipole and L3 magnet) |
IP2 internal crossing angle | -75µrad |
IP2 external crossing angle | 145 µrad |
IP2 effective crossing angle | +70µrad |
IP2 y - vertex shift | -1 mm |
Items | Remarks |
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Filling Scheme | 525ns_140b_124_32_23_16bpi_11inj.csv |
Bunch Spacing | 525 ns (minimal) |
Injections | up to 4 batches of 4 bunches |
Emittance in Stable Beams | 3µm -- tolerable variations: 2µm to 4µm; some spread O(20%-30%) is welcome |
Intensity in Stable Beams | 0.85x1011 ppb -- tolerable variations: 0.70x1011 ppb to 0.95x1011 ppb; some spread O(20%-30%) is welcome |
Profiles | Preparation for VdM : Gaussian profiles which factorise the beam wrt H and V planes |
IP 8 Dipole polarity | + / + |
IP 8 external half crossing angle | 145 µrad; internal half crossing angle : -75 µrad --> effective half crossing angle at IP: 70 µrad which is ok for using the ZDC. |
Injection Optics | With crossing angle to not have problems with LR interactions when beams are large at injection |
BGV measurements | Requested by CMS (to be followed up by LPC) |
The LHCf run is scheduled to start shortly after the first luminosity calibration related fills after TS1 This will probably start around of the 20/9/2022 with up to four days of data taking foreseen.
LHCf will take data with their detector in two different positions. AFP or ALFA roman pots to be inserted as well. The luminosity request is for about 40/nb per detector position. This will take about 26 hours of stable beam per position with 150 colliding bunches.
Items | Remarks |
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Filling Scheme | Multi_525ns_152_150_0_0_8bpi_19inj.csv |
Bunch Spacing | 525 ns (LHCf could go to 200ns, but would require a different filling schemes) |
Injections | up to 4 batches of 4 bunches |
Emittance in Stable Beams | 3µm |
Intensity in Stable Beams | 0.85x1011 ppb |
Beam crossing in IP1 | Vertical, downward |
Luminosity leveling in IP1 | Offset leveled to µ=0.02 |
Beam crossing in IP5 | CMS requested to run with zero crossing - might do some luminosity-related scans |
The 90m run is scheduled for taking place after TS2 when the new T2 detector is installed, nominally around 10/11/2022.
The squeeze for this fill will be very long (40m - TBC) and might go to 120m to achieve the optimal pile-up level.
The TOTEM roman pots will be inserted close to the beam, so there will be no stable beam and beam should stay below "SETUP BEAM" limits (3x1011 protons.
Items | Remarks |
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Filling Scheme | 4 colliding bunches in IP1/5, all well separated |
Emittance in Stable Beams | Ideally 3µm as otherwise need lower intensity or larger ß* |
Intensity in Stable Beams | 0.6-0.7x1011 ppb |
Target pile-up level in IP6 | µ=0.04-0.1 No offset leveling allowed |
Beam crossing in IP5 | Zero crossing |
Target luminosity | About 1/nb - should take around 6 hours |