Configurations for Special Runs / VdM in 2022
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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.
The special run program has been split in two, with the non-linearity scan, LHCf run at 19m and a calibration transfer done right TS1, while the regular vdM scans will be done after MD2
AGK remains unchanged at bucket 31751.
Maximum separation to be requested in MPP: 3 nominal σ for each beam in both planes at the same time for the vdM cycle.. This might require a set dedicated loss map - TBC after discussion with MPP. For low-β optics 3 nominal σ for each beam in one plane at a time is sufficient (this might not actually be enough for the calibration transfer fill). 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 (~1.8µm - to be confirmed for Gaussian shaped beams).
| Step | Duration | Experiments activities | Remarks | |||||||||||
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| Machine recovery and setup of 19m cycle for LHCf run/vdM scans | 2 days | None | ||||||||||||
| Non-linearity measurement fill (3b - 19m optics) | 2h |
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Filling Scheme: Single_3b_0_2_2.csv Stable Beam not required, but it needs zero-crossing angle. It can also be scheduled after the LHCf fills. |
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| LHCf run (19m optics) | 3-4 days |
See details below
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Filling Schemes: End-of-fill test in one fill for ATLAS for crossing angle sensitivity, reducing crossing angle to zero (1 hour) |
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| LHCf removal | 8 hours |
Access to tunnel to extract LHCf detectors
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Has to be done during working hours. | |||||||||||
| Revalidation of low beta* optics | 2-3 days | None | ||||||||||||
| Calibration transfer fill (140b - low ß* optics) | 7h |
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Filling Scheme: Multi_525ns_140b_140_75_16_8bpi_19inj.csv ß* levelling to 30 cm only after first µ scan |
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| 150b - Ramp-up fill with trains | 2h |
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Filling Scheme with 1x36b: 25ns_159b_146_128_134_36bpi_8inj_3INDIV.csv |
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| 600b - ramp up fill | 2h |
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Filling Scheme: 25ns_591b_578_510_540_72bpi_12inj_3INDIV.csv |
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| 1200b - ramp-up fill | 5h |
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Filling Scheme: 25ns_1167b_1154_1022_1088_144bpi_12inj_3INDIV.csv |
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| Normal physics fill | optimal | Back to normal physics data taking ATLAS toroid ramped up before in interfill
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Filling Scheme: 5x36b train with INDIV for LHCb: 25ns_2461b_2448_1737_1733_180bpi_16inj_1INDIV.csv |
| Step | Duration | Experiments activities | Remarks | ||||||||||||||||||||||||
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| 3b setup fill - 19m optics | as needed |
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Setup fill for orbit cleaning and test of IP1 crossing angle change. Collisions, but no stable beam will be declared. |
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| Validation fills | as needed | None |
Two fills with full set of loss maps at flat top and in collisions. Asynchronous dumps at the end of each fill. |
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| Scans IP2/8 - 19m optics |
16h |
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Filling Scheme: LHCb VELO to have at least 0.5mm gap. Ghost charge measurements during LHCb and ALICE scans. ALICE leveled to μ=0.005-0.05 during other scans (set at start of each scan). |
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| Scans IP1/5 - 19m optics |
17-19h |
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Filling Scheme: Part 1 and 2 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 closed to gap 0.5mm. Ghost charge measurements at start of parts 1 and 2, if possible. ALICE leveled to μ=0.05. 2h ATLAS grid scan is only if it fails to be included in the previous ATLAS scan step |
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| 600b - ramp up fill | 2h | LHCb dipole OFF for alignment data |
Filling Scheme: 25ns_591b_578_510_540_72bpi_12inj_3INDIV.csv ATLAS to be separated during this fill to avoid activation |
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| 1800b - mu variation fill (physics optics) | 12h |
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Filling Scheme: 25ns_1815b_1802_1443_1542_180bpi_14inj_3INDIVs.csv High luminosity fill with 3 INDIV bunches (2 collisions at each IP). Normal (1.45x1011ppb) bunch intensity. No ß* leveling foreseen unless needed to bring PU back to requested level of 60. Scan starts fully separated (5 sigma) (OK for OP) |
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| Normal physics fill | optimal | Back to normal physics data taking
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Filling Scheme: Default 2022 full ring with 36b trains 25ns_2462b_2450_1737_1735_180bpi_17inj_2INDIV.csv |
| Items | Remarks |
|---|---|
| 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 |
|---|---|
| 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 |
| IP8 beta* | 24m |
| IP8 Dipole polarity | Down, + |
| IP8 external half crossing angle | -300 µrad; internal half crossing angle : -140 µrad --> effective half crossing angle at IP: -440 µrad. |
| Injection Optics | With crossing angle to not have problems with LR interactions when beams are large at injection |
| 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 |
| Items | Remarks |
|---|---|
| Filling Scheme | 525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv |
| Bunch Spacing | 525 ns (minimal) |
| Injections | up to 2 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 2 Dipole polarity | + |
| IP 2 external half crossing angle | 145 µrad; internal half crossing angle : -72 µrad --> effective half crossing angle at IP: 73 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 after the setup of the 19m vdM/LHCf cycle after TS1. This will probably start around of the 22/9/2022 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 28 hours of stable beam per position with 140 colliding bunches.
| Items | Remarks |
|---|---|
| Filling Scheme | 525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv |
| Bunch Spacing | 525 ns (LHCf could go to 200ns, but would require a different filling schemes) |
| Injections | up to 2 batches of 4 bunches |
| Emittance in Stable Beams | 2µm |
| Intensity in Stable Beams | 1.1x1011 ppb |
| Beam crossing in IP1 | Vertical, downward 290µrad total |
| 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 |