Thanks to all for attending the video meeting. Here are some
minutes; apologies in advance for any omissions or garblings.
Represented experiments: SNO, Super-K, MACRO, LVD, AMANDA, OMNIS
News from experiments:
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-- Alex Murphy reported on a meeting between the OMNIS and MINOS
collaboration. He said that the outcome was quite positive; the MINOS
collaboration is willing not only to consider alternative analyses,
but even to consider modification of their detector design. There is
some possibility of inserting Gd-loaded sheeting in the air gaps
between the scintillator/iron planes. Cost would be in the $100,000
range, to be installed by the start of running in 2002.
-- SNO running is going well; the connector problem remains quashed.
They are sealing against radon.
-- AMANDA will report on a new SNMP (their supernova rate monitor
hardware) analysis at the upcoming ICRC conference. They are working
on an SNMP hardware upgrade. Also 6 new strings will be deployed this
summer.
-- SK, LVD, MACRO: no change in status. There will be no Super-K
upgrade down-time this summer.
Privacy agreement:
-----------------
There were a couple of suggestions for modification:
-- Art M. proposed adding an additional group (an "advisory board"
for lack of a better name) consisting of senior level members from
each experiment, whose function is to "authorize" the members of the
subgroup, decide the high-level security issues, and make it all
official. Everyone agreed that this is a good idea.
-- Another suggestion was to keep a cap on the number of members
of the working group, to keep it down to a manageable size (although
this is not yet a problem.)
I'll modify the draft according to these suggestions and post it
shortly. SNO, LVD and Super-K are all having collaboration meetings
at the beginning of June, which is a good opportunity to have
the privacy agreement approved by the different experiments, and for
an advisory board to be formed.
Time synchronization tests:
--------------------------
I gave a short talk on the "LED time bomb" possibility described in
my previous email. There were several comments and suggestions.
-- There are really two things we'd like to test:
1. Whether each experiment is tagging the event times right,
and
2. whether the whole alarm coincidence system is working, starting
from light in the detector, to the individual software burst monitors,
all the way to the coincidence server and alarm.
For #1, you only need a single LED time bomb that could be
shuttled around from experiment to experiment. Also, a simple
light signal, e.g. a single LED, would be sufficient here.
#2 is harder -- to test several experiments at a time, we need at
least two and preferably more bombs. It's also trickier to set up,
because to test the whole system, you need some kind of stellar
collapse simulation in each detector plausible enough to pass the
software tests (e.g. position uniformity tests for SK and MACRO).
Both LVD and AMANDA reported that they are not currently well set up
to split LED signals. So rigging this test may require hardware
tinkering and/or software twiddling on the part of all experiments --
but may be doable.
Of course, we could do these two tests separately; for a test
of #2, you only really only need timing good to ~seconds.
So maybe we could have several cheap time bombs for #2 and
a single shared high stability time bomb for #1?
-- Clarence V. has spoken to his NRC contact, Rob Douglas at NRC,
whose timing expertise we may be able to draw on. One point was that
a single timing test isn't enough; we will have to keep checking
whether things stay in synch. Experience will show what a reasonable
interval is. We could also look into whether it's possible to borrow
an atomic clock from NRC (a single clock would be good enough for
individual experiment timing tests.) He may have other good ideas.
-- Adam B. pointed out that the time window for a coincidence test
with AMANDA is only a 3-month period during the austral summer (Dec-Feb).
We should consider this when scheduling multi-experiment tests.
-- Ludwig dB. of Duke U. pointed out (by email later) that the
relativistic effect on an airplane is ~0.1 microsecs/day. If we're
lucky enough to get a clock good enough for this to be a problem, we
may need to make corrections!
Next meetings:
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We agreed that another video meeting in about 2 months would
be a good idea. We should also aim for a physical meeting in
the fall.