Configurations for Special Runs / VdM in 2024
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Configurations for Special Runs / VdM in 2024 |
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The planning on this page reflects 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 contact the LPC.
| Step | Duration | Experiments activities | Remarks | |||||||||||||||||||
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| 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 |