Stony Brook Update T.K. Hemmick for the Stony Brook Crew
Many things in these past 2 weeks • Two dry runs of the production were done. • Item addressed from evaporation through to the HBD vessel itself (dry runs revealed areas for improvement). • Easiest way to discuss is to follow the path of a GEM through the system and discuss the items in that order. • Life begins in the Evaporator…
Quantum Efficiency • Some suspicion of QE trouble: • Photocathode read normal current. • PMT read higher than normal current. • QE low by ~20%. • Chicklet test shows that trouble is likely a repair made to PMT system that increased its current without changing the cathodes. • Quantum Efficiency is the normal good result when measured in Bob’s system.
If cryos are cold, Why is it smoking? • Cryo pump compressor makes smoke. • After phone tag: • That is only our brand name, we don’t service it. • Nope, we sold it to them, they have to help you. • Bill opened up the unit and found that the main power switch had developed a resistive character and burned. Rest seems OK.
Need to make QE system faster. • After bad measurement, no fears to change circuit. • Want QE scan to be faster. • New wiring scheme: • pAmmeter no longer floats at 166 V. • Read into LabVIEW DAQ. • PMT and cathode read at same time.
The Low Rider… • First Dry Run revealed that the Evaporator Box was too high when on the rails. • Low Rider: leading wheels go down gentle incline. • Removable bridge: back wheels to drop in slot. • Low work surface. • Locked in place. Removable Bridge
Gain Box modifications. • The lid of the Gain box is difficult to position in glove box. • The gloves get caught in the bolts/nuts. • Nuts now welded to the underside of top lip. • 3 bolts are upright to act as guides to align lid accurately. • Still heavy…what to do…hmmmm…
Hoist System installed to ceiling. • Two hoists ($45 each from eBay) lift the lids of the evap and gain boxes. • Clean and new…no worries.
More efficient data collection from GB • Maestro (PC-based MCA software). • Automated Gain Saturation Curves: • One spectrum every 5 minutes. • Root macros to plot gain curve. • Automated Gain Map: • Prompts user VOCALLY to move cable to next signal. • New patch panel eliminates 50-ohm terminators. • Complete map (56 pads) in one hour!
Finally…the HBD is here. • First (as requested) we cleaned it up on the outside.
Then we mounted it to rotating fixture. • As requested HBD is held principally by straps that run the perimeter. • These straps are made from Industrial Velcro: • Two mushroom-head pieces. • No fuzzies. • Strong, but not extreme.
Then we put it in the glove box. • Frame fits with HBD on it (we knew that). • HBD can be lowered a few inches (no electronics yet). • Rotation allows all but two end-most pieces to be installed nearly perfectly vertically.
Two Connectors Issue: Gas piping!! • These are TWO gas inlet and TWO gas outlet connectors. • Notice that the HV cover boxes (imagine them WITH the SHV) are in the way of a straight connection between these. • Anyhow, do we REALLY want a SS tube running across the active area? • NOTE: The HBD body cannot support the weight of the 3-way valve on the inlet side! • Idea: • Cap one side (North, away from gas supply). • Other side has 3-way valve on flexible bellows hanging now from rotating frame and later from support mounts.
Issue: Debris • With continual use we noticed a few small flecks of debris on the gloves in the glove box. • Dust means microscopic and often airborne. • Debris are tiny pieces of solid. • Searched for and FOUND source: TOOLS! • Removed all tools from glovebox. • Setup (anew) Ultrasound cleaning station. • More thorough cleaning procedure: • Old: Students would alcohol-wipe everything with non-dust wipe. • New: • 60o C-de-ionized water. • 5 minutes each Ultrasonic frequency • Alcohol chase (removes the water). • Argon or nitrogen blow-dry (removes the alcohol).
Miscellaneous • We’re working on a wiki to keep our procedures in: • http://hbd.on-wiki.net/ • Some sections are now quite detailed. • Some meager detail. • Some just playing around. • Please browse by and add pages.
Schedules for Photo-cathode. • Start this weekend or early next week. • Original (leisurely schedule): • 7 days per shot…3 shots…3 weeks. • Reasonable schedule: • 4 days per shot…3 shots…2 weeks. • Outrageous schedule: • 3 days per shot…3 shots…10 days. • These are not particularly accurate until we begin. • Real soon now….