1. Agenda Cooling finger HV-Prep Valve (2-3/4” vs. 4-1/2“) Puck moves = QE falls Prep vacuum & bakeout Abnormal beam shape and orbit from HV chamber

2. Cooling finger Puck/photocathode heated to 580 C (0.5 to many hours) Cooling time to 100 C about 2 hours, to 30 C about 6 hours Would like LL puck cooling time similar to BP (~ 2 hours) Different configuration Prep=heat chamber HV-Prep Valve (2-3/4” vs. 4-1/2”) Longitudinal manipulator alignment is quite good Retraction success is 100% Insertion success is ~95% Puck scraping valve ID progressively worsening Last retraction required “bending” manipulator

3. Puck Move = QE falls On May 30 QE scans vs. puck moves 5.4% initial 4.2% out/in 4.2% no move 3.5% out/in 2.5% out/in 2.2% out/in On May 31 heat/activate and recover 14.1% QE scans on June 2 w/ valve open/closing

4. Prep Vacuum vs. HV-Prep Valve BP Prep base vacuum 10-30 nA (50-90 nA during activation) LL Prep base vacuum 100-300 nA (900-1000 nA during activation) -8 -9 -10 -11 -12 Valve ClosedValve Open Hydrogen Nitrogen

5. Abnormal beam shape and steering from HV chamber Beam from photocathode “center” requires large vertical correction Matt beam steering (4pm good, 10pm bad) Ken electrostatic simulations (effect of cathode tube vs. no tube) Joe mask activation

6. No heat cycle No mask activation (2600,2600) Yes heat cycle No mask activation (2600,2200) (calibrated 4.94 um/step)