Spring 2021 - Rebuilding Photogun

Replace cathode electrode

• "old" existing electrode here : https://wiki.jlab.org/ciswiki/index.php/CIS-ASY-R28-3
• "new" niobium electrode here : https://wiki.jlab.org/ciswiki/index.php/CIS-ASY-R28-1
• leak test large grain Nb cathode/ceramic/flange assembly : << carlos' logbook entry goes here >>
• fiducialize Nb cathode to 10" flange (old method glued fiducials)
• (maybe) fiducialize existing 10" flange to HV chamber
• vent HV chamber, remove cathode electrode, searching for puck tab
• fiducialize anode to HV chamber
• align cathode to anode
• align LM to cathode (after venting depo)
• align HV to chamber Y and re-align laser for retro-reflection

Replace depo schneedle

• Make (2) SS schneedle w/o silver plating, replace depo chamber silver plated schneedle media:ACC2003000-0219 schneedle.pdf
• Galling reduced by addition of Mn and Si

• Nitronic 60 data sheet
• Mir50

• NF3 leak value => leave as-is
• align mask, fix w/ two set screws
• replace K source with Alvatec Sb source?

Fix pucks

• Inspect and mic pucks against series 30 series dwg media:JL0047248 PUCK BODY REV A.pdf media:MoPuckMount.docx

Other jobs

• Re-align HV chamber before venting? => sent request to Gould
• (done) Repair stalk heater driver => https://logbooks.jlab.org/entry/3871902