| Magnet Unit(s) | Half of HER arc defocusing quadrupoles |
|---|---|
| Typical BDES | -40.405 kG |
| Typical Current | 130 A |
| Typical PS Voltage | 680 V |
| Nominal Beta X | 10 m |
| Nominal Eta X | varies |
| Nominal Beta Y | 26 m |
| Nominal Eta Y | 0.0 m |
HER QD90/S3S powers about half of the HER arc QD magnets.
The HER has 6 arcs, each with 16 QD magnets.
In general the HER arcs have QFs and QDs each powered in series for the whole ring except for the seven quadrupole magnets at the beginning and end of the arc. For a general HER arc, these first/last seven are used to generate a dispersion mismatch in the arc which controls (increases) the horizontal beam emittance.
Of the 16 QD magnets in a HER arc, the 9 central QDs are all powered together by one power supply (QD90/S3S). The remaining 7 QDs are powered separately by the QDS family of power supplies to achieve the dispersion suppression scheme. Arcs 1 and 3 however each have one of these dispersion suppressor quads (QDS3 on the outward of IR2 half arc) powered in series with the main arc QDs (QD90/S3S).