Meeting Minutes

Present: Patric Muggli, Collette Pakuza, Benjamin Moser, Stephane Burger, Thibaut Lefevre, Arthur Clairembaud, Edda Gschwendtner

BPMs / BTVs:

• Chromox can likely sustain temperatures of 200 °C, as it is commonly processed at temperatures exceeding 1000 °C.
• Chromox is porous and this property should be taken into account.
• How does temperature influence the light yield?
• Central position of BPMs/BTVs is known with an accuracy of approximately 150 µm.
• New BTV design will use linear actuators.
• Maximum aperture of existing BPMs is 160 mm.
• Interaction of the proton beam halo with BPMs is not ideal, but no obvious problem detected.
• Spare AWAKE BPMs have a 60 mm aperture.
• The last screen in AWAKE will need to be large; screens up to 60 cm are currently used at CERN
• Installing a screen or BPM near the facility end is important to measure the remnant dipole field in the dipole magnet.

Bunch Length Measurement:

• A suitable location for installation of the devices must be identified.
• Possible installation downstream of the second plasma: confirmation required from Eleonora; may require modifications to beam optics.
• Investigation needed to determine if the measurement can also monitor proton bunch modulation.

Upstream Beam Instrumentation:

• Further discussion planned in a dedicated BI (Beam Instrumentation) meeting.
• Coordination required with SY-ABT to determine instrumentation needs for operation.

Basler Cameras:

• Radiation limit depends on camera batch; typically around 10^8 hadrons/cm².

Action Items:

• Marlene / Patric / Arthur: Define the aperture of instruments downstream of the plasma to determine whether existing spare elements can be used.
• Eleonora: Investigate if the electron beam can be transported to the end of the second plasma exit.
• Marlene: Inform Eleonora that this information is needed. If feasible, identify a location for the diagnostic and include routing for laser pulses.
• Marlene / Collette: Contact SY-ABT to clarify proton beamline instrumentation requirements.
• Patric to share conclusions from previous work of screens in Rb vapor by J. Pucek --> results here: : https://indico.cern.ch/event/1007838/contributions/4229397/attachments/2188165/3698057/CLEAR_screensRb.pdf, additional explanation by J. Pucek per email: We ran test at CLEAR with the small vapor source assembly, however, we have never filled it with Rubidium - the leak rate for the small assembly was too high - so in the end we discussed with Patric, that we might perform the test in an Argon atmosphere, but I did not finish the prototype - it needs an argon flushing system.