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

• 4/8 Leak check good, cathode assembly going to S&A for fiducials
• 4/7 Walked S&A jobs w/ Chris, agreed to following:

S&A Gun-to-Y as found 4/9, tell us about Y ports, NEG tube and where cathode is pointing, no idea about anode

We decide if we want to do/move anything and run beam again

We decide when to vent HV and Depo, remembering to look for schneedle, clean out Ag flakes

S&A will fiducialize upstream anode face in UITF

S&A will be able to help us align new schneedle where cathode will go

S&A will be able to align cathode to anode

S&A will be able to align cathode/anode combo on whatever line we want (thinking Y ports)

CIS follows up for puck in/out tests, and laser alignment

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

4/6 - Shop is fabricating two, trying to have one ready by 4/18

one from 304 SS and one from Nitronic 60 https://mis.jlab.org/mis/apps/job_request/mshop/view_request.cfm?request_id=330210&code=1

• 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