gun3 2004 summer shutdown new neg’s - ten 9.5” strips new neg tube – 27 hr. sputtering time
DESCRIPTION
Preliminary SVT4722#2-GUN3 Status (1/12/05). Gun3 2004 summer shutdown New NEG’s - Ten 9.5” strips New NEG tube – 27 hr. sputtering time New cathode – “yellow” 25 deg SS polished to 1um,TRANSCRIPT
Gun3 2004 summer shutdown• New NEG’s - Ten 9.5” strips• New NEG tube – 27 hr. sputtering time• New cathode – “yellow” 25 deg SS polished to 1um, <2pA @ 100kV• New cesiator strips• Sacrificial bulk w/ large Ta cup• Bakeout good – no leaks• Bulk activation 4% at 670 nm w/ UHV ~ 5nA baseline (ELOG1228461)• HiPot stalk out 120kV OK vac burst 110kV & stalk in 110kV OK – cathode OK
SVT4722#2 loaded• No hydrogen cleaning• In solder – no heat in air• 5 mm polished Ta cup • Stalk#4• Loaded into Gun3 on 8/11/04• Bakeout good – no leaks• Cathode heat 1 hr @ 630 C• Activation OK - 5% at 655 nm and 0.65% at 769 nm
Preliminary SVT4722#2-GUN3 Status (1/12/05)
Hall A776 nm
Hall B655 nm
Hall C782 nm
Gun3 SVT4722#2
Heat• 45 min up• 15 min @ 630 • Cool
Reactivate• ~15 yo-yo’s• Vacuum < 20 nA
Hi-Pot• Stalk Out - OK• Stalk In - OK• Typ. 60 A leakage
Notably good injector setup…• Measured beam polarization, surface charge limit, analyzing power• Calibrated HVPS against Pcup• Early demonstration of possible “Qweak”-type beam
ELOG#1202899 SVT4722#3VGUN (Reblochon)
Calibrate laser powervs. attenuator over relevantrange…
Measure photocurrentvs. laser power twos ways…• 200 A ramp• 100 A + 100 A ramp
QE vs. laser power at 776 and 782 nm• one makes sense, the other less so…
Analyzing power is low, but not zero…• A ~ 2.1% B ~ 0.2% C ~ 2.2%
Physics started Saturday, but poor transmission…
No more orbit shifts.Good transmission.
Sunday, on-call• Corrected orbit at 1I03/1I04 – transmission fully restored (good)• Hall B1 picomotor to reach 30 nA – too far (spot move!)
Hall A776 nm
Hall B655 nm
Hall C782 nm
QE vs. Time (yet), because…• Daily charge plot app not working – Bickley will fix…• StripTool “archiver feature” does not dump data…• Archiver for gun current is running at 5 Hz (eek!) – too much data, too late…
Hall B “spot move”
New “starting line”
Efficiency numbers…
Bulk Strained Superlattice
Max. P 35% 75% 85%
QE* [%/mW]
At Max. P6% 0.2% 0.6%
Sufficient “I”
Experiments12% 56% 72%
Limited “I”
Experiments0.7% 0.1% 0.4%