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This update provides information on the progress of HBD detectors at Stony Brook, including improvements in handling strategies and test results. The update also discusses proposed upgrades and future plans for the detectors.
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Stony Brook UpdateGetting Serious about HBD East T.K. Hemmick for the Tent Crew
HBD West Progress • Vlad and Bhartendu report that ALL 6 stacks that tested well at lower voltage also test well at higher voltage. • My personal theory: • We have improved the dust situation a lot in the glovebox, however, it is still not perfect. • Assuming that the failed stacks are individual GEMs, this means that only 85% of the GEMs that passed the gain box tests survived the full installation procedure. • Matt Durham has proposed a new procedure that the Stony Brook Group fully endorses to make East quicker and better.
When were the bad stacks installed? • Is there a trend toward worse survival at later install dates? Time Installed *swapped out top GEM
New Idea • Glove box is hard to work in • Glove box is bad for GEMs • So only use it when necessary • Put in all copper GEMs on laminar flow table (cleanest spot in room) • Once those are in and tested, put vessel in glovebox and install CsI GEMs
Continuing the West Detector: • Finish a few tests: • Perform the “bump test” on the good stacks to prove that they survive some mild detector motion. • Push the bad stacks to see if they any be improved without opening. • Locate which GEMs are the trouble by powering them individually. • Swap in some new GEMs: • Push out the CF4 with N2 • Change out the individual bad GEMs. • Single-GEM test all stacks in GB atmosphere. • Close up and push CF4 • Repeat present suite of HV tests. • Remove West from Glovebox for bench tests. • 3 weeks???
Start prepping the East Detector NOW!! • Upgrades: • Shades (I prefer not). • Cube & quality feedthrough. • New HV boards • New R-cards: • Original chain? • Modified chain? • Wash & Test Cycle: • Some existing Cu GEMs need washing. • Wash the pock-marked Au-GEMs and select the very best of these. • Test all these GEMs (3 at a time) in the test box near the laminar table. • Install detector into rotating frame after upgrades completed. • Install ALL Cu GEMS into the detector with the detector at the laminar table. • Flow CF4 through the East detector and thoroughly HV test all the Cu GEMs. • Install the HBD into a thoroughly cleaned glovebox. • Evaporate 10 Au GEMs; install the directly into the HBD; close and begin HV tests of the completed device. • Trigger on cosmics in forward bias to verify operation of the GEMstacks.
TKH’s opinion: • Way to go Matt!! • I believe that glovebox handling is the opposite of clean handling. • Our experience has limited failures ENTIRELY to dust-induced HV ills. • This strategy eliminates glovebox handling of all Cu GEMs and verifies their operation in the HBD vessel before it enters the glovebox. • This strategy cuts by more than a factor of two the CsI GEM handling in the glovebox. • This strategy is MUCH quicker than the previous. • I believe that this will build a better HBD.