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Milagro Observatory Update
Brenda Dingus
4/20/2007
Power Outages
• Need one computer (sparks) to come back to life after
long (several hours) outage
• sparks controls the switches which allow us to reboot the
other computers
• sparks was a Dell laptop, but wouldn’t restart when
power came back
• sparks is now a Mac laptop, but the Mac can’t
communicate with the switches
• Bought a new switch that’s supposed to be Mac OS
compliant, but maybe the Mac is too old
• Does anyone have a newer Mac that we could use?
CAEN High Voltage
• Communication with mems died twice such that
the voltages and currents are not read out for
the EMS page and are not controllable via gohv.
• Both times gohv was running when this
happened.
• DON’T RUN gohv ANY MORE.
• Replacing a chip fixed the problem the first time
(Sep. ‘06), but not the second time (yesterday).
• This HV chassis is no longer made by CAEN.
• Replacing the chassis means replacing the pods
as well. Total cost $30-40k.
Disk Archiving
• RAID Kings have been dying.
• Being replaced with higher density disks.
• How much space do we need?
– Store data (gamma, crab, rec, grb) for
transport on portable to LANSCE
– Store RAW data for TBD weeks
• TBD was ~6 weeks
• HOW MUCH RAW DATA SHOULD WE STORE?
Trigger Rates
• New shorter time window trigger was implemented
~January 10.
– Crab should be ~ 4 sigma since then.
– CAN SOMEONE VOLUNTEER TO CHECK.
• Gives more stable rate and higher % fit
• However, no ice last winter. Due to early, large snow fall,
the ice layer formed above the cover.
• Rate did decrease in winter due to ~15cm water
equivalent on top of cover. Multiplicity rate was lowered
to give ~ same total rate.
• Pumped water off cover. Only lost ~2 cm of water out
the drain.
– SHOULD WE REFILL AND ADD MORE WATER?
Outrigger Trigger
• Purpose is to improve effective area for high
energy gammas off the pond.
• Should be small increase in total trigger rate.
– I’ll measure rates next week on Wed.
• Need more MC simulation to identify best trigger
for high energy gammas
– 185 ns gate is not long enough to get all OR for larger
zenith angles
– Could combine lower multiplicity from individual
patches
To Repair or Not to Repair
• Currently ~20 dead MU pmts & ~20 dead AS
pmts
• Need to remove curtains that are around 2 pmts,
but this could be done independently
• Maybe we could repair in June???
– Water is cold, but air is warm and usually no
thunderstorms
• September may interfere with HAWC proposal
Misc.
• SIGN UP FOR SHIFT
• 2 Person Rule being revised
• WACT pads, buildings, mounts and mirrors scheduled to
be demolished
– Does anybody care?
• Next collaboration meeting date
– ICRC preliminary papers due May 31 (final Aug 15)
– ICRC July 3-11
• Need HAWC meeting soon
– Resubmit proposal in Sept.
– Panel review in Oct?
– LANL wants to do review prior to panel review