| Magnet Unit(s) | PR02 3101 |
|---|---|
| Typical BDES | 77.573 kG/m |
| Typical Current | 50 A |
| Typical PS Voltage | 10 V |
| Nominal Beta X | 77 m |
| Nominal Eta X | 1.1 m |
| Nominal Beta Y | 2 m |
| Nominal Eta Y | 0.06 m |
LER SCX2 is one of four SF magnets (SCX1,SCX1L,SCX2,SCX2L) in IR2 used to locally cancel the horizontal chromatic effects of the strong IP focusing.
In the early planning of the LER IR2 optical design it was planned to include both horizontal and vertical chromaticity correction locally within the straight much as is done with a "final focus". Space and budget constraints however led to a more modest design in which the horizontal chromatic correction is done within straight 2 (taking advantage of the bending necessary to overlap the beams at the IP and then separate them), and the vertical chromatic correction is done with strong sextupoles layed out strategically in the adjacent arcs.
The horizontal IP chromatic correction is done with two pairs of SF magnets (SCX1,SCX1L,SCX2,SCX2L) one pair on each side of the IP.
The SCX1 magnets are placed ~4 m outboard of the QF2 strong focusing magnets, and the optics are taylored such that there is very little horizontal betatron phase advance between such that SCX1 has the same phase as QF2. The SCX2 magnets are placed further out (~13 m and 180 degrees of horizontal betatron phase) such that SCX1 and SXC2 form a sextupole pair which together cancel the horizontal chromaticity introduced by the QF2 magnets.