Passive absorbers in IR3 to protect the Warm Q5
Description
The accumulated dose on the insulators of the magnet coild will be one of the major causes of failure for the warm mangets in the cleaning insertions (dog-let dipoles and warm quadrupoles in IR3 and IR7) and in the high-luminosity points (warm sepration dipoles in IR1 and IR5). In order to mitigate this effect, 3 passive absorbers per beam were added in IR7 to protect D3 and Q5, and 1 per beam was added in Ir3 to protect the D3 olny.
It is proposed now to install a passive absorber the closest possible to the Q5 in IR3 in order to maximise the effectiveness of the magent protection, which would extend the lifetime of this quadrupole magnet. This requires moving existin BPMs further away from Q5. Detail description is found in the ECR (link).
The first magnets in Q5 are MQWA.E5L3.B1 and MQWA.E5R3.B2, the absorbers are proposed to be installed as close as possible to Q5 (moving existing BPMs) and matching the Q5 aperture (30H 52V cm).
Proposed positions
| Slot name | s coordinate [m] | Distance to the IP [m] |
|---|---|---|
| TCAPD.6L3.B1 | 6511.663 | -153.056 |
| TCAPD.6R3.B2 | 6818.2568 | 153.536 |