Azriel Goldschmidt

1
String-18 Progress and Plans

• Azriel Goldschmidt
• AMANDA/IceCube Collaboration Meeting
• Laguna Beach, CA March 2003

2
String-18 Progress and Plans

• Fast Communications
• changes to firmware and software done
• 35 DOMs can now (finally!) handle 350 kBaud
• Upgrade to 525 kBaud or higher possible
• Now working on surface DAQ bottlenecks
• Data compression/bandwidth studies with string-18
  waveforms, relevant for string-18 and IceCube
  -see Klaus H.s talk-
• Plan for software data reduction/compression
  running on ARM
• Remains to be seen if ARM can handle the load

3
String-18 Progress and Plans (cont)

• Improved understanding of waveforms
  discriminator noise, pedestal pattern, ringing,
  etc, by Seckel_at_Bartol
• Improved understanding of time correlated light
  in DOMs -see Klaus H.s other talk-
• This has implications for both String-18 and
  IceCube
• Surface DAQ bug fix during 02/03 season thanks
  Holger!
• Time calibration to global clock to lt 3.5 ns
• Tested VLF antenna effect on communications

4
String-18 Progress and Plans (cont)

• New Flasher Runs
• for Kurt Co (is it still bumpy?)
• for further understanding of timing/software
  trigger
• New LED trigger capabilities (for PMT transit
  times and gain calibration)

5
Example of a Flasher Event Times and Waveforms
ATWD 1.8 ns/sample
FADC 60 ns/sample
6
Another Flash
7
Waveform Studies Lots of progress from a fresh
look by Seckel
Ringing
8
Waveform Studies Lots of progress from a fresh
look by Seckel (cont)
Discriminator noise
9
Waveform Studies Lots of progress from a fresh
look by Seckel (cont)
Discriminator noise, distinct from pedestal
pattern...
10
String-18 (Digital) VLF immunity
11
Plans

• IceCube effort has currently higher priority, but
  if resources are allocated
• First remove surface DAQ data bottlenecks
• Second implement software data reduction
• Third Implement online trigger (string processor
  implied)

12
ATWD and ADC waveformsExample 3 photons in 2
microseconds
ns/sample
ATWD0 High GAIN

1.7 ATWD1 Low Gain

1.7
ATWD2 Nothing

1.7 ATWD3 Clock

1.7
ADC
60
217 ns
7.7 ms
Time Sample Number
13
Muon Data Checking timestamps with coincidences
from consecutive OMs
T (DOM N)
12 m
T (DOM N1)

• DeltaT T (DOM N) - T (DOM N1)
• Zoom around -1,1 msec
• Mean at -24 nsec
• Consistent with expectation for downgoing muons

14
Example Muon Event 1
Late Hit

• Only first hit in each OM shown
• Down flow of light
• Late hits consistent with light scattering

Late Hit