Spring 2021 - Rebuilding Photogun

HV chamber : Replace cathode electrode

• Electrodes

• "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 >>
• S&A jobs (will walk with Chris Gould 4/7 @ 9am UITF)

• fiducialize Nb cathode to 10" flange (old method glued fiducials)
• (maybe) fiducialize existing 10" flange to HV chamber
• fiducialize anode to HV chamber
• align cathode to anode
• align LM to cathode (after venting depo)
• align HV to chamber Y

• re-align laser for retro-reflection
• vent HV chamber, remove cathode electrode, searching for puck tab

Depo chamber : Replace schneedle, fix pucks, opportunistic jobs

• Make (2) SS schneedle w/o silver plating, replace depo chamber silver plated schneedle media:ACC2003000-0219 schneedle.pdf

• fabricate one from 304 (like print, but w/o plating)
• fabricate one with less galling than 304/316 (addition of Mn and Si)

• Nitronic 60 data sheet (Nitronic trademark AK Steel)
• Mir50 (Mir50 trademark ASC Steel)

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