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 05/03/2021

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 :https://logbooks.jlab.org/entry/3878165 SbPt bead on W wire installed as 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)
• 316L SS and Nitronic schneedles made, cleaned and tested in pucks #8, #22, and #31

Return 10" flange

Align floppy mask to puck on heater, fix mask (comments: Marcy and Mamun looked at the mask assembly, the two screws that hold the mask on the rod are found tight, it is teh rod that wobble, we experience similar wobbling at GTS mask assembly too. :https://logbooks.jlab.org/entry/3878166

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