Configurations for Special Runs / VdM in 2024
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Configurations for Special Runs / VdM in 2024 |
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This page reflects the planned program in 2024. Items like the times scans took were not updated after data-taking. In case of doubts do not hesitate to contact the LPC (or in case inconsistencies/mistakes are spotted).
| Step | Duration | Experiments activities | Remarks | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scans IP1/5 - VdM optics |
~18h |
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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 Ghost charge measurements throughout the full program, if possible. Alternatively, at least at the beginning of parts 1 and 2. |
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| Length Scale Calibration - VdM optics |
~7h |
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Filling Scheme: Can happen in the same fill as the previous one, if the beams are still good. If the fill is dumped, it will be incorporated in the Scans IP2/8 below. |
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| Scans IP2/8 - VdM optics |
~10h |
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Filling Scheme: 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. |
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| Calibration Transfer fill with indivs ("CT-indivs") - physics optics |
~7h |
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Filling Scheme: 525ns_140b_140_75_16_8bpi_19inj_800ns_bs525ns Download ß* levelling to target (40-50cm) only after first µ scan at 120cm. ATLAS ok to go up to pileup 68-70. |
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| Calibration Transfer fill with trains+indivs ("CT-trains") - physics optics | >12h |
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Filling Scheme: 25ns_2211b_2198_1854_1974_108bpi_27inj_3INDIVs Download ATLAS ok to go up to pileup 65. |
| 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 |
| Items | Remarks |
|---|---|
| Filling Scheme | 525ns_138b_136_35_16_8bpi_19inj_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 |
| Items | Remarks |
|---|---|
| Filling Scheme | Multi_72b_60_20_22_4bpi_20inj_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 |
| 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 | TDIs fully open, BRANs retracted |
| Injection Optics | With crossing angle to not have problems with LR interactions when beams are large at injection |