DOM Testing

1
DOM Testing

• Julien Balmont
• For
• Hagar Landsman

2
Facts about FATs

• Every DOM deployed is being tested once in the
  north and once on Ice at the SP.
• 900 DOMs were already tested this year, starting
  May 2006.
• 5 freezers are used for testing (1 DESY, 1
  Uppsala, 3 UW)
• Each test cycle is 3 weeks long at the north,
  and 2-3 days at the pole.
• The temperature is cycled between -45c and room
  temperature in 5 steps.
• A set of 7 tests is repeated on every temperature
• There are 205 parameters on every temperature
  that are checked on every DOM.
• All the results DOM by DOM are available online
• From now on, FATs will be running non stop

3
The tests

• Temperature
• Room temperature
• -45Oc
• -55Oc (IceTop only)
• -20Oc
• Room Temperature
• -45Oc (long soak)
• Unload

• Tests
• STF
• Local coincidence
• DOMCal
• Optical sensitivity vs. Wave length
• Dark rates (high gain)
• Reboot tests
• Testdaq runs
• Time resolution
• Dark noise w/wo LC
• Linearity

4
Main failure modes

• Noisy/Spiky Dark rates of DOMs are higher or DOM
  is spiky Less than last year.
• Reboot DOMs are being rebooted and moved to
  iceboot as the temperature decreases. Every DOM
  that fails more than once will stays here.
• Flasher board Flasher boards that completely
  failed are being replaced.

5

• A summary of the test results is available
  online.
• This includes
• A summary page
• DOMCal summary
• A monitoring summary
• Optical sensetivity summary
• Time resolution summary
• Failed STF summary
• NCM form for failures
• In addition all raw tests result are available in
  the /data/exp/IceCube/ directories under FAT
  and under TestDAQ

(CW, HL)
6
A Spiky DOMColonel Korn (FAT22)
7
Data collected in FAT

• Dark rate runs (Monitoring)
• Time resolution
• Linearity
• Optical sensitivity

8
Monitoring Example of analysis

• Capture Dark rates for 24 hour in every
  temperature 6 days in the second -45 soak
  high gain for 24 hours.
• Spike finder
• Correlate spikes between DOMs in time.
• Remove spikes for averages and fitting
• Histogram, fit to gaussian, obtain width and
  mean.
• Alert on spiky DOMs

(CW, HL)
9
Analysis of single spikes Desy fat6 at -45 (HL)
40
39
38
37
48
47
46
45
Top shelf
33
34
35
36
41
42
43
44
56
55
54
53
64
63
62
61
Bottom shelf
49
51
52
57
58
59
60
8
7
6
5
16
15
14
13
50
2
3
4
9
10
11
12
1
Top shelf
A map of DESYs DFL. Each circle represents a
station. Stations were a spike was found in the
same 1 sec window are colored in the same
color Clear geometrical pattern is seen.
24
23
22
21
32
31
30
29
Bottom shelf
18
19
20
25
26
27
28
17
10
Time Resolution Analysis by Chris Wendt
Pulser pulsing at
Laser
setup
fiber
Synch. board
DOM
t1
t0
11
Droop correction based on FAT data Analysis by
Juande Zornoza

• Data used for this analysis- Linearity run
  Brigth2048-FW5 files. Taken in FATs.

• We fit the first part of the waveform to an
  exponential

• Then we reconstruct iteratively the wave form

• DOMDroop table with the tau constants for each
  DOM and temperature (room, -20, -45, -55 0C) have
  been included in the domprodtest database on both
  fat-dbs.icecube.wisc.edu and bergy.lbl.gov.

12
Optical sensitivity Analysis developed by Chris
Wendt

• Check DOM response for different wave length

Determined by DOM Quantum
efficiency Gel Sphere Glass PMT
Glass Ref. PMT Quantum efficiency PMT
Glass Optical system Fiber length Temperatur
e Wavelength Optical efficiency artifically
lowered Using sun screen (HL, Phil Roth)
13
Gel batch check
Optical eff
(HL)

• Each marker represent a single DOM.
• Each color represent a different gel batch.
• Different efficiency distributions are clearly
  seen between batches.
• All within the spec.

14
Summary

• DOMs are being tested non-stop through out the
  year. As we speak FATs are running !
• A lot of data is collected. You can use it !
• All information- Raw and Processed is online.
• See South pole talk for details on OnIce testing.
• See Production talk for details onProduction

15

• Thanks to all the 2006 FAT operators
• UW
• Brennan, Claire, Erik, Jessica , Jon Eisch,
  Karen, Phil Roth, Sean
• DESY
• Julien, Bernhard
• Uppsala
• Leif, Adam