1. Stony Brook Update: T.K. Hemmick for the Tent Crew

2. Test box ready and given to Ilia • The test box was equipped with feet and the leaks were (mostly) sealed. • The windows were sealed with an extra ring of DP190 glue…works. • When the window seals were complete the next major leak was at the shaft for the source. • The source shaft repair involved cleaning away old grease, replacing O-ring with slightly thicker one. • The new shaft is sealed UNLESS it is torqued to one side or the other and then it leaks. • Handles were not installed. • Box was delivered to Ilia Wednesday.

3. ULPA Vac has an impact: • The ULPA Vaccuum arrived Wednesday. • The HBD vessel was closed for the cleaning to protect contents from flying dust and allow for the possibility of opening the glovebox for a permanent ceiling mount of the vacuum. • As second (final) “blow test” of the gain test box produced only minor increases in the dust level (50  400) as compared to the previous blow test (50  10000).

4. Water from ULPA vacuum • Although the vacuum was passed through the air lock disassembled (to avoid the burp of trapped air), its many interior surfaces nonetheless trapped some water. • Initial turn on of the vacuum spiked the water levels in the glovebox, but fortunately, the HBD was closed and flowing UHP Nitrogen. • The eventual solution was to turn on the vacuum and leave it on for hours. • The water went from 6.9 ppm over 40 ppm and then slowly decayed below 10 ppm before we turned the (now quite warm) unit off. • NOTE: Air exhaust from the vacuum registers zero dust particles of any size we can measure (0.3 microns and up) during any reasonable count time. • This is consistent with its rating as an ULPA device.

5. Cleaning Results • During the water purge, the vacuum was used to clean the HBD from one end to the other. • The initial result was that all visible surfaces seemed clear from debris. • The later result was that the dust meter when placed on the floor improved considerably: • Floor before: Class 200 • Floor after (Saturday morning): Class 20

6. Decision on Quad-GEMs • If we indeed go with the quad-GEM solution we must make modifications to the vessel for the new wire grids and re-route the internal HV connections. • This requires disassembly of the 4 stacks inside, removal of the HBD from the glovebox, and hardware work. • A preferred solution would be Ilia working with Bill Lenz on the mechanics • In this case, we should decide and act soon.

7. Idea for new grid mechanics • Bill Lenz correctly points out that the HV connection posts were not intended as precision devices and not placed with high precision. • Grid mount points, do require high precision. • A simple solution is to precisely position a piece that glues to the top of the HV block carrying the extra HV points as well as the extra mounting points for the grid.