| Magnet Unit(s) | PR02 3012 |
|---|---|
| Typical BDES | 44.488 kG |
| Typical Current | 800 A |
| Typical PS Voltage | 50 V |
| Nominal Beta X | 89 m |
| Nominal Eta X | -0.26 m |
| Nominal Beta Y | 17 m |
| Nominal Eta Y | -0.02 m |
LER QF2R is part of the LER IR2 strong focusing scheme which achieves the small IP beta functions (betax ~0.5m betay ~0.015m).
Located close to the IP at z = +/-3 m, QF2s are the closest LER electromagnet focusing elements to the IP. The magnets are unusual in that they have wide aperture (to accommodate the large beta function), are strong (to achieve the strong focusing), and are septum magnets. The septum feature is to allow a field free region within the magnet's frame to allow HER beam to pass. Inboard of QF2 the HER and LER share magnetic elements.
Together with permanent magnets QD1 which are inside BaBar at z = +/-1.8m, QF2s focus the LER down at the collison point. QD1s; being centered on the HER, leave the LER beam offset horizontally by ~3cm providing additional (horizontal) separation for the LER.