| Magnet Unit(s) | PR12 1112 PR12 4152 |
|---|---|
| Typical BDES | -21.137 kG |
| Typical Current | 80 A |
| Typical PS Voltage | 75 V |
| Nominal Beta X | 4.8 m |
| Nominal Eta X | 0.3 m |
| Nominal Beta Y | 24 m |
| Nominal Eta Y | 0.0 m |
LER QD1R01,R11 is one of a family of arc magnets (QD4,QF4,QD3,QF3,QD2,QF2 and QD1) which are used to match the dispersion at the beginning and end of the arcs adjacent to straight 4 (tune, RF) and straight 12 (tune). These are the only two LER straights in which the horizontal dispersion function is entirely zero by design, and that is achieved by these magnets. These magnets are sometimes called "dispersion suppressors".
As the names indicate, these seven arc quadrupoles are configured such that one power supply powers two magnets located symetrically about the straight (i.e. one magnet near the end of the upstream arc and a partner magnet near the beginning of the downstream arc).
The QD4 magnets are the first/last quadrupoles in the straight, and the family progression from there leaves the QD1 magnets furthest into the arcs.
In arcs 1 and 3, the QD1 magnet is pushed further inward by an additional eight magnets to allow an additional scheme to modulate the beta function at the SCX4 and SCY4 IR2 local sextupoles, but this scheme is not presently done.