Spring 2021 - Rebuilding Photogun

Depo chamber : Replace schneedle, fix pucks, opportunistic jobs

• Vent Depo Chamber

Pump out NF3, plan to leave leak valve as is ->> DONE 04/30/2021

Vent Depo chamber (isolation valve - bake line - pump) ->> DONE 04/30/2021

Remove and mic pucks vs. series 30 series dwg, clean, fix media:JL0047248 PUCK BODY REV A.pdf media:MoPuckMount.docx

• Pucks removed 04/30/2021
• Pucks measured

Pucks as of March 31 2021 Link to UITFLOG entry

Media:UITF pucks in HV and prep chambers as of March 31 2021.jpg

HV chamber

Puck # 14 is missing its tab (ear). It has bulk GaAs last activated March 31 2021, good QE

Depo chamber

Puck # 31 Bulk GaAs Used many times, not very good QE

Puck # 8 Bulk GaAs used as dummy for HV conditioning

Puck # 22 SSL perhaps never activated?

Add pucks => new bulk GaAs on X pucks + special one for HV conditioning?

Replace K source with Alvatec Sb source

Mamun found Russ' Sb req : https://misportal.jlab.org/reqs/pr/viewPrPo.do?prNum=315281

Replace w/ Nitronic schneedle (make sure fit to pucks good first), set alignment into electrode w/o or w/ puck

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 316 or 316L 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)
• won't use this ... although probably not a problem, can be mildly magnetic Mir50 (Mir50 trademark ASC Steel)

Return 10" flange

Align floppy mask to puck on heater, fix mask

HV chamber : Replace cathode electrode

• Electrode Prep Work

• "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

LgGnNb leak check => done 4/8, Carlos leak tested complete assembly in 1137

LgGnNb fiducialize => done, Chris provide Carlos this info to compare assembly to assembly Media:R28_3_S&A_Inspection_Apr-14-2021.xlsx

• Alignment Jobs in Cave

Walk job with Carlos & Chris => done 4/7

S&A perform an as-found of the Gun through Y chamber => media:UITF Y Chamber Line April 22 2021.xlsx

Link to UITFLOG entry on SA& results and comments

Matt's "Have-Want" summary pics media:210414_HaveWant.pptx

Decide if we want to run beam before venting => don't think so, agree at 4/15 UITF meeting

• Vent HV Chamber to replace cathode (isolation valve - bake pump - turbo)

Start depo jobs first to be ready for manipulator alignment

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

Other jobs

• Improve stalk heater driver motion => done, https://logbooks.jlab.org/entry/3871902