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7th Injection Design Meeting
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Europe/Zurich
354/1-019 (CERN)
7th Injection Design Meeting
**Attendees:** Justin, Daniel, Jim, Marlene (detailed discussion); Nicolas, Vittorio, Edda, Eleonora (general discussion)
**Discussion points:**
* **Y-Piece:**
* Action: Add screens for e-beam alignment to injection region pipe extensions (need to ensure compatibility with the e-beam magnets).
* Two vapor sources will be angled (maximum angle is 0.1 mrad, possibly smaller if the proton bunch doesn’t experience all of the dipole field).
* Material inside the dipole magnets will need to have a magnetic permeability smaller than 1.005; need to find adequate materials.
* Need to decide where the Galden flow will turn around → better further upstream to ensure uniformity in the accelerator plasma.
* The electron beam may need to be centered in the apertures to avoid kicks. Can we define a number for the tolerance?
* Action: Need to finalize the Rb injection and flow near the injection region.
* **Expansion volume:**
* Screen and camera included; for now, only one screen position and no Rb blocker yet (need to ensure full retraction). Action: update.
* What can/should the expansion volume viewport be looking at?
* Patric: all the important components of the expansion volume seem to be there.
* This third expansion volume adds one more cold trap.
* Need to check where to place the valves (likely further upstream due to space constraints).
* Whether 30 cm of space is sufficient still needs to be verified by simulations.
* **E-beam commissioning chamber:**
* Special chamber for e-beam commissioning; could be that there will be no Rb yet at this time. Need to be discussed with planning in mind. Action.
* Does not need to be designed yet.
* **Laser dump in the injection region:**
* No response from L. Ranc yet to question from Daniel on previous data.
* Need to do more concept work. Action.
* Need to clarify how many hits a foil can take and what the procedure would be to change the foil (may need to happen quite frequently).
* It will be the first time that the foil gets hit from both sides.
* Possibly do tests on a laser system.
* **Chillers:**
* Dimensions: 450 × 450 × 800 mm + 50 cm of space needed at the back to access the chillers.
* Each chiller has two water connections (in/out) and two Galden fluid connections (in/out).
* Chillers are filled from the top (need access) and have a display on the front (which needs to be visible).
* The pipes will need to be insulated.
* There is a maximum length over which the chillers can pump fluid (normally water; with Galden, which has a higher viscosity, not specified) because of the pump capacity due to friction.
* We only know that what we have right now (25–30 m?) works.
* **Racks:**
* Need to ensure that all 8–9 racks for the vapor source are located together. --> Action: Marlene
* Need an additional 4 × 24U racks inside the tunnel, at the end of the cable connections → Marlene to find space with integration; can be on either side of the beamline. Action.
* Will need to update DICs with connectors and ensure that the cables run effectively to these racks in the tunnel.
* **Gap in the floor shielding:**
* 80 cm transverse space should be sufficient.
* Bath can also be on the standard shielding blocks.
* Action: Add interferometer arms into the drawing and share with F. Galleazzi.
* **Mu-metal shielding of the 18 MeV line and the two vapor sources:**
* Will need to be discussed in a separate meeting.
* Discuss how the existing shielding may need to be modified.
* Action: Eleonora to check if all or part of the 150 MeV beamline also needs to be shielded.
* **Planning:**
* Installation of vapor sources may be staged.
* Need to define when cables are needed. For cabling to be executed early on, need to update cable requests with connectors soon.
* Need to clarify which parts will be reused (vapor source parts, supports, etc.).
* Q1/2026: Milestone to know that what is planned is in principle feasible; resolved conflicts with e-beamline and space.
* 2026: Component design.
* Justin to update planning with the latest version from Eloise.
* Introduce GWA and new fellow (Tobias) ASAP.
* Design of control system in 2027.
* Can the Y-piece be tested separately?
* GWA to estimate cost.
---
**Action follow-up:**
* Action: Eleonora to check with Vittorio and Philip the functional specs of existing magnets and assess the margin within the current optics → Not executed, as Eleonora is redesigning the line to move the waist upstream.
* Action: Vittorio and Philip to clarify which of the last five beamline magnets (dipole, corrector, octupole, sextupole, quadrupole) can be opened and how. * Further action: Check the field uniformity requirements of the dipole magnets and whether assembly in the tunnel is likely going to fulfill these. Check if any spare magnets are available.
* Action: Eleonora to shift the optics waist upstream by \~21–24 cm, keeping current magnet positions or, if needed, redesigning the line with the same magnets. Conclusions to be shared with GWA (time estimate: by end of the month) → No news yet. Discussion in a separate meeting on the 10th of September put that work on hold until the experiment provides specifications. This was not understood from the experiment. → Action: Marlene agreed to fill specifications ASAP to avoid further delay.
* Action: Eleonora and Maria-Carmen to choose the type of flange for the connection between the BPM and octupole chamber. → Will be reevaluated once the new beamline design is available.
* Conflict between the last sextupole and the vapor source: Whether a new sextupole design with a smaller footprint is feasible will be confirmed in a couple of weeks by Vittorio. --> Action: report back.
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