| Magnet Unit(s) | PR02 2142 |
|---|---|
| Typical BDES | 21.170 kG |
| Typical Current | 80 A |
| Typical PS Voltage | 20 V |
| Nominal Beta X | 77 m |
| Nominal Eta X | -1.1 m |
| Nominal Beta Y | 4 m |
| Nominal Eta Y | -0.02 m |
LER QFCX1L2 is one of a family of quadrupole magnets (QFCX1,QDCX2,QFXC3) in straight 2 which set the optics appropriate for the local horizontal 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 QFCX family comprise five magnets per side. The sequence is QFCX1,QDCX2,QFCX3, QDXC2,QFXC1 with the sequence repeated on the other side of the IP. each of the four QFCX1 magnets has it's own separate power supply. All four QDCX2 magnets share one power supply, and both QFCX3's share one power supply. This allows for equal beta x at a pair of 180 degree separated sextupoles which achieve the chromatic correction.