Stony Brook Update T K Hemmick for the

Зарегистрируйтесь, чтобы просмотреть полный документ!

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

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… 2

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. 3

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. 4

Need to make QE system faster. • After bad measurement, no fears to change circuit. • Want QE scan to be faster. • New wiring scheme: – p. Ammeter no longer floats at 166 V. – Read into Lab. VIEW DAQ. – PMT and cathode read at same time. 5

The Low Rider… Removable Bridge • 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. 6

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… 7

Hoist System installed to ceiling. • Two hoists ($45 each from e. Bay) lift the lids of the evap and gain boxes. • Clean and new…no worries. 8

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! 9

Finally…the HBD is here. • First (as requested) we cleaned it up on the outside. 10

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. 11

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. 12

Issue: Gas piping!! Two Connectors • 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. 13

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 nondust 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). 14

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. 15

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…. 16

Скачать презентацию Stony Brook Update T K Hemmick for the

389bf20a5a3f77177b457119518a8657.ppt

Количество слайдов: 16