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Stony Brook Update

T.K. Hemmick for the Stony Brook Crew

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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…

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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.

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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.

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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.

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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

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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…

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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.

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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!

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Finally…the HBD is here.

• First (as requested) we cleaned it up on the outside.

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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.

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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.

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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

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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).

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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.

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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….