1. Update on 8” MCP Coating in Beneq
Jeffrey Elam
December 20, 2011
Large Area Picosecond Photodetector Group Meeting
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2. Coating 8” MCPs in Beneq
300 mm chamber

3. Flow Restrictors

4. First Coating with Flow Restrictors – no MCP
JE1421: 12/16/2011, 500c TMA/H2O, no MCP, flow restrictors installed
612
625
628
flow
632
631
630
629
627
625
629
625
G=1.25
ds%=0.78
mm%=3.19
614
With flow restrictors installed and 1 s H2O, works great! (still no MCP)

5. First Coating with Flow Restrictors and MCP

6. Summary of Coating Experiments

7. Summary of Coating Experiments
No MCP – all look pretty flat.
With MCP – all show hump. Hump gets worse with larger H2O exposures
Hump is seen in both x and y. Appears at borders of MCP, shifted downstream in x-direction
Hypothesis – our biggest problem is that the MCP is trapping H2O. This is released during TMA dose, diffuses out in all directions. Where TMA meets H2O we get a hump.

8. Extreme Example
JE1417: 12/14/2011, 500 c TMA/H2O, MCP suspened 12mm over plate
793
918
677
827
716
801
913
779
731
967
837
682
839
955
G=1.54
sd%=12.8
mm%=33.6
759