1. Outgassing studies DC Spark Corrected calibration Mo and Cu data with same calibration data and same experimental environment Field emission measurements on the damaged SLAC sample

2. Motivation Results used for vacuum quality simulations Material differences? Connect outgassing properties to breakdown resistance?

3. Calibration Extrapolation from nitrogen calibration was expected to be OK for order of magnitude studies In the particular system used, a separate algorithm is used to give hydrogen current, hence a separate calibration is absolutely needed Sorry!

4. Cu results revisited Pumping speed ~0.02 l/s of nitrogen No argon or water found (differing from measurements by T. Ramsvik on molybdenum)

5. Cu results revisited Fixed energy 0.8 J Integration time 4 min Amount of released hydrogen and CO gas about the same

6. Mo results Fixed energy 0.95 J Ratios are the same Same gases Slight overall increase Result is within range of what T. Ramsvik measured No significant material difference observed!

7. Mo conditioning Virgin spot on cathode No change in outgassing rates Seems there is some energy dependence

8. SLAC sample Virgin spot in damaged area Difficult to know if the high peaks are probed Fowler—Nordheim plot, so steeper curve means lower field enhancement (beta) I do not trust this value to be real

9. SLAC sample A re-run of field emission measurement at same spot Beta change from 2 -> 40 Spot not been subjected to more than 1µA

10. SLAC sample Voltage increased in steps of 2 V (usually 50 V) Observe some discrete current jumps Lower trigger limit for field emission?