Mark Krasberg

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Penguin Training
DOM-related material
Madison, Wisconsin
Mark Krasberg, May 29th, 2007
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The Design
9 strings and 16 IceTop stations deployed
2005-2006

• 1 Gton instrumented volume
• gt70 strings of 60 Digital Optical
  Modules (DOMs)
• 1450-2450 m deep
• 17 m spacing
• 125 m hexagonal grid
• geometry optimized for
• detection of TeV PeV ns
• DOMs look downward
• No single point failure
• 1 cable/2DOMs
• IceTop air shower array
• 2 surface tanks for each
  string/station (2m
  diameter)
• each tank contains 2 DOMs

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The IceCube Neutrino Telescope
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A three hour flight from McMurdo to South Pole
Station, via C-130 Hercules
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The DOMs
Each DOM is an autonomous data collection
unit Power consumption 3W

• Measure arrival time of every photon
• 2 Analog Transient WD digitizing at 300 MHz
• for 400 ns (signal complexity) and FADC
• recording at 40 MHz FADC 6.6 ms (event
• duration in ice)
• Dynamic range 500pe/15 nsec
• 25000 pe/6.4 ms
• Can do local coincidence triggering
• transmits to surface at request via digital
  communications
• Send all data to surface over 3.3 km twisted pair
  
• copper cable power, data and time stamping

25 cm Hamamatsu PMT
Main board
PMT base
Clock stability 10-10 0.1 nsec /
sec Synchronized to GPS time every 5 sec at a
precision rms 2 nsec (Rapcal calibrations)
LED flasher board 12 LEDs
33 cm Benthosphere
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DOM Testing
Final Acceptance Test

• Check basic DOM optoelectronic function
• Perform extended life and stability tests of DOMs
  in temperature cycled environment over weeks
• Calibrate DOM optical sensitivity

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S-CUBE 64 mainboards Used to test all DOMHubs
prior to shipment to Pole
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• Working time Nov. - mid-Feb
• Plan deploy 14 strings/season
• Completion 2011

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Deployment of 39-01
Frigophobia
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Single photoelectronpulses recorded with ATWD
10 pulses are superimposed

• Single photoelectron pulses (SPE) recorded in 6
  DOMs during the final acceptance test.
• All PMT gains are set to 1E7.
• Threshold at 0.3 SPE
• FWHM13.6 ns

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Pulse shapestaken in situ

• Pulse shapes are recorded with three ATWD
  channels for high dynamic range coverage.
• Runs of 10 flasherboard pulses at 5 different
  brightness settings are shown.
• High saturation in channel 0 (high gain), but
  good coverage of the brightest pulses in channel
  2 (low gain).

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String 39 two-week freeze-in movie
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DOM Hookups

• Cables
• 2 DOMs per twisted pair
• 2 twister pairs per quad cable
• 15 quad cables per InIce Cable (60 DOMs)
• Local Coincidence
• Each DOM talks to its neighbors on either side
  (UP and DOWN)
• A neighboring hit can be used to cut down rates,
  confirm the signal is real
• Depending on which DOM is the neighbor, the
  electronic LC signal has to travel between 17
  meters and 51 meters

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1,403 Commissioned DOMs

• There are 1,424 deployed DOMs
• 1,387 DOMs were commissioned by seasons end!
  (now 1,403)
• IceCube-9 596 of 604 DOMs commissioned
• Same as end of last year
• Zero failures as a result of DOMs being turned
  off for several weeks!
• Of the 596, two have broken LC and one has broken
  HV
• Other 8 two are on the debug hub sps-wczar
  (Juneberry, Alfa_Romeo_Spider)
• 13 new strings and new IceTop 807 of 820 DOMs
  commissioned
• Only one DOM, 74-09 Immunology, does not power
  up
• Twelve DOMs are on the debug hub, sps-wczar.
• Four pairs are high current, under study
• One pair has 56-58 Tengu which didnt freeze-in
  until around May 10
• Last year, Fusilli didnt freeze-in until the
  beginning of May
• One pair communicates very badly
• Of the newly commissioned DOMs
• 58-45 Kokolik_River suffers from SHDR and
  DOMCal cannot calibrate its HV
• 1E7 gain tuned by eye
• One DOM requires a special DOR firmware setting
  (66-45 Alpaca)
• 72-33 Mahischa, 72-35 Ant_Nebula and 72-43
  Spirograph have broken LC (like 39-08 Shamal
  and 50-58 Universitet from last year)

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Problematic DOMs

• A few DOMs do not power up at all (pretty
  serious!)
• zero from 04/05
• four from 05/06
• one from 06/07 (broken connector may be the
  culprit)
• Several wire pairs exhibit high current
• At least two categories
• Ultra-high current DOMs
• 3 wire pairs (6 DOMs total)
• there may be a solution, based on a DOM
  Arizona, which was detected as being high
  current at the pole and returned to Wisconsin
• Marginal high current DOMs
• 7 DOMs total
• Associated with broken LC
• a DOM called Haifa is under study may yield
  answers
• Clustering of high current DOMs from 06/07 is not
  understood
• 2 DOMs broke down last year, 2 DOMs from this
  season have very poor communications

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40-51 Juneberry 40-52 Alfa_Romeo_Spider
poor comms
50-58 Universitet bad LC
39-08 Shamal bad LC
59-59 Cosmology poor flash
38-59 Blackberry no HV
29-18 Yurei PMT?
49-17 Biometeorology bad flash
30-23 Peugeot_505 no power
50-36 Ocelot no power
29-59 Auroraphobia 29-60 Nix no power
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string 58 67 66 74 73 65
72 78 48 57 47 46 56
High Current / LC breaks on the 13 new strings
High Current DOMs
Does not power up
LC break
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Some of these DOMs are high current pairs
(partners could be fine)
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Over 1,000 DOM years of operation in the ice so
far !
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76 DOMs
589 DOMs
1390 DOMs
39-22 Liljeholmen stops communicating properly
30-60 Rowan stops communicating properly
0/76 has a 1-sigma upper limit of 1.8
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76 DOMs
589 DOMs
1390 DOMs
39-22 Liljeholmen stops communicating properly
30-60 Rowan stops communicating properly
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Polar Ice Optical Properties
Scattering
Absorption
Average optical ice parameters ?abs 110 m _at_
400 nm ?sca_eff 20 m _at_ 400 nm
Measurements ?in-situ light sources ?atmospheri
c muons
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Data taken with 22 strings on Feb 11, Animation
made a few hours later at pole with help of Phil
Roth, Georges Kohnen 49-57 Popcorn is
flashing 378 DOMs fire All 22 strings are hit!
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How to tell if a run is good

• The penguin training wiki has
• Link to monitoring pages
• Path towards a good run list document
• Monitoring status list (2006)
• Carstens run summary
• John Pretzs good run list
• Ayas good run list
• Obviously, the definition of a good run is not
  standardized
• My guess is that in the near future there will be
  a definitive good run list

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How to refer to a DOM

• The official way to refer to a DOM is by location
  and name
• 29-54 Nomatophobia
• The names stick out, problems become easier to
  track and identify
• DOMs have other identifiers
• DOMid TP5P0647
• Electronic mainboard id fe6b36e170cc

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Were there any high current DOMs found during
surface testing?
Arizona was a high current DOM during surface
testing. DOM name recognized on shelf in the TOS
during deployment! DOM pulled from hole. The
proudest moment in the history of the DOM names!
Arizona just arrived at PSL. Current draw
increases as voltage increases!
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IceCube-9
Photographs of Frigophobia and the IceCube
drill camp taken by Mark Krasberg, 2006
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IceCube-22