Presentation on theme: "1 Stony Brook Update T.K. Hemmick for the Stony Brook Crew."— Presentation transcript:
1 Stony Brook Update T.K. Hemmick for the Stony Brook Crew
2 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…
3 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.
4 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.
5 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.
6 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
7 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…
8 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.
9 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!
10 Finally…the HBD is here. First (as requested) we cleaned it up on the outside.
11 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.
12 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.
13 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. Two Connectors
14 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: 60 o C-de-ionized water. 5 minutes each Ultrasonic frequency Alcohol chase (removes the water). Argon or nitrogen blow-dry (removes the alcohol).
15 Miscellaneous We’re working on a wiki to keep our procedures in: –http://hbd.on-wiki.net/http://hbd.on-wiki.net/ Some sections are now quite detailed. Some meager detail. Some just playing around. Please browse by and add pages.
16 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….