Monitoring
Burn-off efficiency
A common figure of merit used to quantify the condition of the LHC is the lifetime of the beam. It provides important information for the LHC as a storage ring, but does not inform about the luminosity production of the collider. Instead, it is more appropriate to define the instantaneous burn-off efficiency \eta, following:
where \left[\tfrac{dN}{dt}\right]_\text{total} and \left[\tfrac{dN}{dt}\right]_\text{bo} are the total and burn-off losses, N is the beam intensity, \mathcal{L} = \sum_{\text{IPs}}\mathcal{L}_\text{IP} is the total luminosity of the collider, R_\ell is the loss rate from non-burn-off losses and \sigma_\text{pp} = 80\ \text{mb} is the accepted value for the cross section of proton-proton collisions at 7 TeV. The efficiency is similar to the effective cross section \sigma_\text{eff}= \frac{1}{\mathcal{L}}\left[\sigma_\text{pp} \mathcal{L} + R_\ell N\right] used in previous work. One can note that \eta = \sigma_\text{pp}/\sigma_\text{eff}. To optimise luminosity production, a well-behaved machine needs to lose most of its protons to collisions, i.e. \eta \to 1. Assuming small R_\ell over a short period of time compared to the length, T, of luminosity production for a fill, one can show that the relative gain in integrated luminosity, G, scales with the integral of \eta(t), or more precisely: $$ G \sim -r_0\left[\frac{r_0 T + 2}{r_0 T + 1}\right] \cdot \int_0^T\left(\frac{1}{\eta} - 1\right) dt $$
where r_0 = \sigma_\text{pp} \mathcal{L}_0/N_0 is a constant which depends on the initial conditions (with units of \unit{s^{-1}}). Alternatively, one can see that \left(\frac{1}{\eta} - 1\right) = \frac{R_\ell N}{\sigma_\text{pp} \mathcal{L}} corresponds to the luminosity-normalized losses of the machine. For example, if \eta = 0.5 for 30 minutes in typical LHC conditions (N_0 = 2400\cdot 1.3\times 10^{11}\ \text{p}^+ and \mathcal{L}_0 = 2\times (2.2\times10^{34}\ \text{Hz/cm}^2)), the change in integrated luminosity is G \sim -3\ \% for T=10\ \text{h}. Hence, the experimental efficiency is to be discussed on the basis of its deviation from \eta=1 over a certain period of time.
Special fills
Fill | Comments | Efficiency | B-by-B signature |
---|---|---|---|
8348 | MD8043, Nov 2022 | DBLM | BCTF | DBLM | BCTF |
8462 | MD7003, Nov 2022 | DBLM | BCTF | DBLM | BCTF |
8469 | MD7003, Nov 2022 | DBLM | BCTF | DBLM | BCTF |
8470 | MD7003, Nov 2022 | DBLM | BCTF | DBLM | BCTF |
Fill-by-fill monitoring
Extra fill-by-fill summary data can be found on the BPT Dashboard
Fill | Wires status | \beta^* | Bunches B1/B2 | Efficiency | B-by-B signature |
---|---|---|---|---|---|
8685 | OFF | 30.0 cm | 411/411 | DBLM | BCTF | DBLM | BCTF |
8686 | ON | 30.0 cm | 399/399 | DBLM | BCTF | DBLM | BCTF |
8690 | ON | 30.0 cm | 399/399 | DBLM | BCTF | DBLM | BCTF |
8695 | ON | 30.0 cm | 911/911 | DBLM | BCTF | DBLM | BCTF |
8696 | ON | 30.0 cm | 999/999 | DBLM | BCTF | DBLM | BCTF |
8701 | ON | 30.0 cm | 999/999 | DBLM | BCTF | DBLM | BCTF |
8723 | ON | 30.0 cm | 399/399 | DBLM | BCTF | DBLM | BCTF |
8725 | ON | 30.0 cm | 999/999 | DBLM | BCTF | DBLM | BCTF |
8729 | ON | 30.0 cm | 1163/1163 | DBLM | BCTF | DBLM | BCTF |
8730 | ON | 30.0 cm | 1163/1163 | DBLM | BCTF | DBLM | BCTF |
8731 | OFF | 30.0 cm | 1818/1818 | DBLM | BCTF | DBLM | BCTF |
8736 | ON | 30.0 cm | 1818/1818 | DBLM | BCTF | DBLM | BCTF |
8738 | ON | 30.0 cm | 1818/1818 | DBLM | BCTF | DBLM | BCTF |
8739 | ON | 30.0 cm | 1818/1818 | DBLM | BCTF | DBLM | BCTF |
8741 | OFF | 30.0 cm | 1903/1903 | DBLM | BCTF | DBLM | BCTF |
8746 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8754 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8771 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8773 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8775 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8786 | ON | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8804 | OFF | 30.0 cm | 2374/2374 | DBLM | BCTF | DBLM | BCTF |
8822 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8850 | OFF | 30.0 cm | 705/705 | DBLM | BCTF | DBLM | BCTF |
8853 | OFF | 30.0 cm | 1195/1195 | DBLM | BCTF | DBLM | BCTF |
8858 | OFF | 30.0 cm | 1650/1650 | DBLM | BCTF | DBLM | BCTF |
8860 | ON | 30.0 cm | 1886/1886 | DBLM | BCTF | DBLM | BCTF |
8863 | OFF | 30.0 cm | 1650/1650 | DBLM | BCTF | DBLM | BCTF |
8865 | ON | 30.0 cm | 1650/1650 | DBLM | BCTF | DBLM | BCTF |
8870 | OFF | 30.0 cm | 1886/1886 | DBLM | BCTF | DBLM | BCTF |
8873 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8877 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8880 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8882 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8885 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8887 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8891 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8894 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8895 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8896 | ON | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
8901 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
9017 | OFF | 30.0 cm | 399/399 | DBLM | BCTF | DBLM | BCTF |
9019 | OFF | 30.0 cm | 911/911 | DBLM | BCTF | DBLM | BCTF |
9022 | OFF | 30.0 cm | 1178/1178 | DBLM | BCTF | DBLM | BCTF |
9023 | OFF | 30.0 cm | 1886/1886 | DBLM | BCTF | DBLM | BCTF |
9029 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
9031 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
9035 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9036 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9043 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9044 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9045 | OFF | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9046 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9049 | OFF | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9050 | OFF | 30.0 cm | 2358/2358 | DBLM | BCTF | DBLM | BCTF |
9057 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9063 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9070 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |
9072 | ON | 30.0 cm | 2464/2464 | DBLM | BCTF | DBLM | BCTF |