200 kV Polarized Gun

• The 200 kV gun (R30-3 with spherical electrode and 18" gun HVC) was installed in CEBAF during SAD 2023.

• This gun performed as designed in terms of vacuum, and high voltage: no field emission at 200 kV after conditioning with Kr to ~240 kV.
• It has two problems:
  • The beam waist is ~ 6 cm downstream of the GaAs wafer, compared to ~ 40 cm from the Tee electrode 14" HVC R28-2 gun operated in CEBAF for years at 130 kV.
  • It was a not possible to obtain the laser retro-reflection.
• The gun was then removed from the injector and replaced with the R28-2 gun.
• The SAD 2024 links below capture the planning for fixing these problems in the R30-3 gun (which will be version R30-4) and for installing it in May 2024.

R30-4 200 kV Gun SharePoint site

R30-4 200 kV SharePoint site

Contains:

• Pierce cathode end piece geometry and beam parameter space table
• Notes, studies, and documentation
• Electrostatics and beam dynamics modeling and simulation results

R30-4 200 kV Gun SAD 2024 Planning Meetings

• >Jan 05, 2024
• >Jan 10,2024
• >Jan 17, 2024
• >Jan 24, 2024
• >Jan 31, 2024
• >Feb 7, 2024
• >Feb 7, 2024

R30-3 200 kV Gun SAD 2023 Installation Links

• ATLIS => https://tasklists.jlab.org/atlis/tasks/108541
• Marcy's Gantt chart goes here => https://jeffersonlab-my.sharepoint.com/:x:/g/personal/marcy_jlab_org/EUe-xbLpNR1IsV28fyi20FUBC4bUllOnMnAYlXemA7C82Q
• List of photocathodes at end of Phase 1 (5/10/2021) - https://logbooks.jlab.org/entry/3876517

R30-3 200 kV Gun SAD 2023 Planning Meetings

• Feb 20, 2023 => * Carlos SAD schedule Media:Gun swap planning 1 week before and 1 week after SAD start.pptx
• Feb 02, 2022 => Feb 2, 2022 - Group meeting - Group meeting + 200 kV gun
• Jan 26, 2022 => 200 kV Gun - Jan 26, 2022

Links

• Carlos 18" Gun Page
• Gun Anode - Carlos's update https://wiki.jlab.org/ciswiki/index.php/Anode