Cast of characters: S. Coutu*, M. Goretti, H. Jeon, E. Katsavounidis**,
S. Kyriazopoulou, P. Saggese, S. Stalio
Notice this "US" group consists of 3 Italians, 2 Greeks, 1 Korean and 1 French
Canuck!
* Your humble reporter
** USPIC, in this case U-SPIC Greek
Wow, folks! It had been over two years for me since I visited these hallowed
hollow Halls. If you haven't been here in a while, be prepared for a
shock! What organization (imagine looking for tools or manuals, and FINDING
THEM!)! What beautiful external facilities (brand spanking new, large comfy
offices, still each with a bathroom-cum-shower)! What interesting-looking
doodahs, doohickeys, thingamajigs and watchamacallits everywhere! What an
incredibly smoothly running instrument we have, with only relatively minor
maintenance to be performed! Many people are to be commended for a lot of
hard work that is now paying off...
You probably don't read these shift reports that get mailed out periodically.
You should, but you're probably a very busy physicist with lots to do. Well,
let me tell you, you might sorely regret it if you skip this one... Money is
involved!
First, the boring stuff:
THE DATA RUNS
- Data-taking has been relatively uneventful (boring is good!), with
exceptions noted below.
- For the first week of my shift, the streamer tube gas system kept tripping
off, about once a day, allegedly owing to pressure changes in the tunnel
due to weather outside (the poor Italian shifters kept getting calls at the
wee hours of the morning to drive in and reset the darn thing). It seemed
to stabilize in the second week.
- After the March 13 calibrations, a few hiccups were encountered restarting
the runs, nothing a good slap in the back couldn't cure. (Similar glitches
were encountered on March 20.) One new hot tank on the South face had to be
turned off, and then overnight a group of four contiguous 3T tanks (13-16)
proved to not register any ERP hits. This is apparently a known occasional
problem (although still unresolved) after calibrations are performed, and
the fix (applied on March 14) was to reload the ERP LUTs for the problem
tanks (this was done also for the noisy South tank which behaved
subsequently).
- In the night of the 14th to the 15th, CIT monopole in uVAX 3 developed a
case of the hots (only episodically however), causing increased dead time (up
to 15%) and shorter runs (one run was half as long as usual) filled with
junk. The increased trigger rate was due to 5T10, yielding essentially 100%
triggers/activity. All other 5T channels also showed unusually high
activity (although a normal trigger rate). The master CIT monopole trigger
for 5T is suspected and will be investigated (could be overheating);
Stefano reports that one PMT in 5T10 has experienced a gain drop of
~ 50% in 4 months (probably unrelated). No such episode has been observed
since.
- In the night of the 15th to the 16th, the acquisition system hung up (causes
unknown, everything looking normal) while trying to end a run, resulting in
a 7-hour dead time before a new run was manually started in the morning. This
occurs once or twice a month and prompted Erik to request that the MACRO
DEAMON be allowed to reset and restart the instrument upon finding it has
hung; so far, this has been resisted by the powers that be.
- On several occasions, the Pisa system lost synchronization with the rest of
the acquisition, necessitating reboots of the Pisa uVAXen.
- The big fan at the North end of the instrument was found off in the morning
of March 18, with the air temperature in the northern half of the instrument
having risen to 30 C, and some crates showing temperatures as high as 42 C.
An expert was called in, the proper breaker reset, and the fan restarted,
which eventually cooled down the hottest crate to 35 C. During the hot
interval, data rates fluctuated more than normal. At 6pm the same day, the
fan shut down again. This time the fan-man found a melted wire somewhere in
the circuitry. Some kludge was effected, the fan was restarted, and has kept
running since. The guards have promised to keep an eye on it.
- On March 21, from 6 am to 4 pm, power to the underground laboratories was
switched to the backup (diesel-powered) system for some work by ENEL.
Although allegedly protected by UPS units, some of LeCroy HV power
supplies were tripped off by the transitions, resulting in a bit of down
time. After normal power was restored, it became apparent the next day
that there were inter-ERP problems (found by BMON), although everything
else looked normal. This is under investigation. (Cycling the power on the
inter-ERP crates has not helped.)
- TOHM trigger activity for 4E10 has been high, increasing steadily, causing
the dead time on uVAX 2 to be higher than normal (2% instead of ~1.3%).
Stefano checked the tank and it appears to be ok, so that we're looking at
an electronics problem. The overall trigger rate for CIT monopole on uVAX 2
is a factor of ~2 higher than normal due to that one channel.
THE CALIBRATIONS
March 13:
- No calibrations had been performed last week due to a problem with the
interpretation of the last calibrations performed on February 28. An ntuple
with the calibration results for the LED TDC run showed a funny 2-valued
structure when TDC was plotted as a function of delay. It wasn't clear for
a while whether the problem lay in the data or the processing software.
By carefully studying the raw numbers, Maurizio, Erik and Stephane
eventually determined that there was a bug in the code used to create the
ntuple in the first place. The calibration data was actually fine.
Maurizio and Stefano thus proceeded to run the gamut of calibrations
for SM 1 and 2 on March 13.
March 20:
- Calibrations were performed for SM 3,4 by a linear combination of Paolo,
Stefano and Maurizio. A fun time was had by all.
THE MAINTENANCE
March 13:
- Stefano fixed a faulty PMT base in 1N04, and reactivated tank 5E03 on which
he had worked the week before (bad PMT replaced).
- A CAMAC crate in SM 6 (that with the master scintillator trigger module) had
a problem with its +12 V power supply constantly getting dragged down to
something like +8 V. After many attempted fixes involving swapping power
supplies and/or the fan unit under the crate, Maurizio eventually
determined that the effect was due to one particular kind of
module (a BU stepper motor controller module) in that particular crate (the
same module in other crates would not cause this). Maurizio and Stephane
swapped the entire crate with a spare one, which fixed the problem.
- Paolo investigated 3 bad CSPAM channels, two of which were fixed when a
connector was repaired and a cable reseated. The third one is still a
mystery.
March 20:
- Maurizio found that two cables bringing reference PMT signals into ADCs
for the SM3/4 laser system were wrongly connected (who? why? for how long?
unknown). Swapping them with the correct ones solved a nagging lack of
signal.
- Stefano replaced the old style bases in 5T10-1 with new ones. This end
had been dying in the last few months, as mentioned above. The tank end
is now enjoying a second go at life.
- After surveying dangling cables in the instrument (many of which were only
partially and/or wrongly labeled, if at all), Stephane reconnected a number
of North face LEDs (1N02-0, 1N02-1, 1N04-0, 1N06-1, 1N07-0) and the ERP
N face computer busy input to the ERP supervisor's IN INH input, all of
which had sat disconnected for reasons and durations unknown. He labeled
or removed all other danglers. Failing to label cables is a mortal sin.
Trust me, I checked the Santa Bibbia, and you go straight to hell for
this, so don't do it again.
- He (the author, like Caesar, enjoying referring to himself in the third)
also proceeded to get a head start on Spring cleaning by vacuuming off
incredibly thick layers of dust on assorted crate filters. It's a wonder
we haven't been frying more modules.
OTHER STUFF
- Sophia is continuing her assessment of the efficiencies of the new TOHMs by
looking at attico low-light level LED data collected a few weeks ago.
She is working on extracting efficiency curves for all TOHM channels.
Preliminarily, it looks like 90% triggering efficiency is reached at about
40 photo-electrons.
- Paolo finished building a test bench for the new TOHM cards and is itching
to start using it. He has been studying CSPAM/HIPT/FMT rates; the structure
of the intra-SM vs extra-SM hits seems to point to two ribbon cables
possibly connected upside-down. This is under investigation.
- Stefano finished setting up his Mac-based CAMAC test platform and has been
studying the behavior of various faulty CAMAC modules, such as waveform stop
masters. He reinstalled/closed/straightened out the doors to the back of
the electronics racks which were in a state of major disarray.
- Hunmoo is putting the finishing touches in his software to control and
verify every aspect of the LED system. He is continuing his work on LED
monopole calibrations.
- Erik is studying past occurrences of the apparent flagging of the same
tank having fired multiple times in the ERP GC within one event. This
occurred in various supermodules, but following a recognizable pattern
of two hot tanks, two normal tanks, indicative of a stuck bit somewhere...
This problem seems not to be present in current data.
THE FUN STUFF
And now, for the first (and very probably the last) time ever, from the
only country in the world where a squeegee is an essential bathroom
accessory, with in mind the goal of constant betterment of the experiment
and the alleviation of the tedium of shift taking, we proudly bring you:
................ Drum roll.................
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
The GREAT MACRO TREASURE HUNT*
It's safe! It's fun! Everybody can play, everybody can win!
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
* No purchase necessary, no salesman will visit, void where prohibited
o Do you find yourself shirking from your shift duties, preferring instead
to send the same student again and again to take all of your
institutions' shifts?
o If and when you come on shift, do you spend most of your time reading
Email or thinking up stupid contests instead of doing something useful
for the experiment?
o Are you at the Gran Sasso for an extended time, trying very hard to
think up ways of avoiding going in the tunnel for honest work?
Take heart! Come to Italy, roll up your sleeves, get down in the tunnel, look
around you for something to do that would be useful for the experiment, or a
maintenance item that has long gone untended, ....., and you could win BIG !!!
Five treasures have been hidden in the experiment, in the form of envelopes
containing sums of money somewhere between 1000 and 500 billion lire. In the
process of doing something useful, you might come upon a hint, or even a
treasure itself, and become a big winner!
The only requirement is that if you locate a treasure, you let me know which
(they are numbered), and what you were up to at the time (especially if it
was illegal or immoral). Your name will be posted for all to admire, as a
Person-Useful-to-MACRO! Fame, as well as Fortune, will be yours everlasting!
Upon my next return to Italy (date as yet unspecified), I will retrieve all
unlocated treasures and be dismayed (but less poor).
Buona fortuna a tutti!
Your Master-of-Unceremony,
Stephane