| Magnet Unit(s) | 2082,2122 3102,3142 |
|---|---|
| Typical BDES | 18.017 kG |
| Typical Current | 70 A |
| Typical PS Voltage | 60 V |
| Nominal Beta X | 35 m, 78 m 77 m, 36 m |
| Nominal Eta X | 0.61 m, -1.13 m 1.13 m, -0.62 m |
| Nominal Beta Y | 3.6 m, 2.3 m 2.2 m, 3.7 m |
| Nominal Eta Y | 0.01 m, 0.04 m 0.06 m, -0.006 m |
LER QFCY1 is one of a family of quadrupole magnets (QFCY1,QDCY2) in straight 2 which would set the optics appropriate for the local vertical chromaticity correction which compensates the chromatic effects of the strong IP focusing.
LER straight 2 is not straight. Rather, there is both horizontal and vertical bending necessary to have the two beams overlap at the IP then extract into the nominal HER/LER beamlines. The resultant dispersion is also advantageously used for a local correction scheme of the horizontal chromaticity generated by the IP focusing magnets. In this way LER straight 2 looks much like a "final focus".The original design for LER IR2 was to have both horizontal and vertical chromatic correction systems use sextupoles within straight 2. However due to spacial and budget constraints only the horizontal correction was done within straight 2. The vertical correction is done with sextupoles out in the adjacent arcs.
The lack of SD vertical chromatic correction scheme within straight 2 greatly simplies the QFCY/QDCY magnet family requirements.
The QFCY/QDCY family comprise four magnets per side. The sequence is QFCY1, QDCY2, QDCY2 then QFCY1 with the same pattern on both sides of the IP. All four QFCY1 magnets share one power supply, and all four QDCY2 magnets share another power supply.