Preliminary SVT 47222 GUN 3 Status 11205 Gun

Preliminary SVT 4722#2 -GUN 3 Status (1/12/05) Gun 3 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 1 um, <2 p. A @ 100 k. V • New cesiator strips • Sacrificial bulk w/ large Ta cup • Bakeout good – no leaks • Bulk activation 4% at 670 nm w/ UHV ~ 5 n. A baseline (ELOG 1228461) • Hi. Pot stalk out 120 k. V OK vac burst 110 k. V & stalk in 110 k. V OK – cathode OK SVT 4722#2 loaded • No hydrogen cleaning • In solder – no heat in air • 5 mm polished Ta cup • Stalk#4 • Loaded into Gun 3 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

Gun 3 SVT 4722#2 Hall A 776 nm Heat • 45 min up • 15 min @ 630 • Cool Reactivate • ~15 yo-yo’s • Vacuum < 20 n. A Hi-Pot • Stalk Out - OK • Stalk In - OK • Typ. 60 m. A leakage Hall B 655 nm Hall C 782 nm

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 SVT 4722#3 VGUN (Reblochon)

Calibrate laser power vs. attenuator over relevant range… Measure photocurrent vs. laser power twos ways… • 200 m. A ramp • 100 m. A + 100 m. 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…

Sunday, on-call • Corrected orbit at 1 I 03/1 I 04 – transmission fully restored (good) • Hall B 1 picomotor to reach 30 n. A – too far (spot move!) No more orbit shifts. Good transmission.

Hall A 776 nm Hall B 655 nm Hall C 782 nm

QE vs. Time (yet), because… • Daily charge plot app not working – Bickley will fix… • Strip. Tool “archiver feature” does not dump data… • Archiver for gun current is running at 5 Hz (eek!) – too much data, too late… New “starting line” Hall B “spot move”

Efficiency numbers… Bulk Strained Superlattice Max. P 35% 75% 85% QE* [%/m. W] At Max. P 6% 0. 2% 0. 6% Sufficient “I” Experiments 12% 56% 72% Limited “I” Experiments 0. 7% 0. 1% 0. 4%