MILOM information page

--- P R E L I M I N A R Y ----

Last update : 30/11/2010 15:39:53

 

Pictures for slides are in color, jpeg full quality, 1024 pixel wide.

Pictures for publications are in eps, 75 mm wide,  arial 10 pt font size, black and white.

General

What's this? For slides (jpeg) For publications Description and comments
MILOM scheme with description of the elements
ppt version
Soon Carr/Bertin - 09/06/05
Humidity and temperature in the junction box Soon Humidity and temperature in the junction box, 2.5 years since the deployment at a depth of 2475 metres. The top points show the relative humidity. The bottom points show the temperature at two measurement points.

(Blue points and green points have not the same behaviour because...)

Hallewell - 16/06/05

 

Electronics and timing

What's this? For slides(jpeg) For publications Description and comments
A SPE waveform example Soon The top plot shows the waveform of a single-photoelectron obtained from the ARS with a 640 MHz digitisation frequency (each bin is therefore 1.56 ns). The bottom plot shows the ARS digitisation of the main clock system signal. The period is 50 ns (20Mhz). See Sotiris presentation at CERN.

S. Loucatos

A charge distribution corresponding to a SPE signal. Soon This plot shows a typical charge distribution for single-photoelectron signals. It was obtained from the integration of digitised waveforms as shown on previous picture (after baseline subtraction). See Sotiris presentation at CERN.

S. Loucatos

Evolution of a "single-photoelectron" charge distribution with the ARS threshold. Soon This plot shows typical distributions for single-photoelectron signals. They were obtained from the integration of digitised waveforms as show on previous picture (after baseline subtraction). The ARS threshold was varied from AAA to BBB pe. See Sotiris presentation at CERN.

This needs more explanations and details.

S. Loucatos

Clock stability
Measurement of the delay in the clock system between the shore station and the MILOM SCM 209 Kb Measurement of the delay in the clock system between the shore station and the MILOM SCM as a function of time during more than 50 days of operation.

P. Payre

Clock stability - Time delay between SCM ant top LCM 222 Kb  Measurement of the time delay in the clock system between the SCM and the top LCM as a function of time during more than 50 days of operation.

P. Payre

Internal LED flashing
Internal LED flash : time offset stability 198 Kb A walk effect correction is included.

First plots : Signal from the internal LED flashing on 2 OMs (RUN 11176).

Third and fourth plots : Mean time of the internal LED flash versus time since MILOM was connected. OM0 is absent from third pot, and present only at the end of the period for the fourth plot.

M. Melissas

196 Kb
190 Kb
 
Led/Laser beacon timing
Illumination of MILOM 3 PM storey with LED beacon at bottom
ppt version
No eps version Illumination of MILOM 3 PM storey with LED beacon at bottom.

Carr/Bertin - 09/06/05

LED beacon rise time 201 Kb Rise time distribution of the LED beacon pulses with an example of the associated wave form signal as recorded by the LED beacon associated PM (Choose one of the two plots).
 
Laser beacon rise time 203 Kb Rise time distribution of the laser beacon pulses with an example of the associated wave form signal (Choose one of the two plots).
201 Kb
Example of a distribution of time differences between two optical modules on the same storey.

  First plot : Example of a distribution of time differences between two optical modules on the same storey. Both were flashed by the LED beacon; Hits in coincidence lead to the peak which width is around 0.75 ns (thus leading to a time resolution of 0.75/sqrt(2) per PM). This distribution was obtained with large amplitude pulses so that the TTS width effect is negligible.

Second plot : Offsets variation between the 3 optical modules of the storey as a function of time since the MILOM connection. The time offset is computed as the gaussian mean. The offsets measured after immersion are compatible with those measured in the laboratory at the 0.5 ns level.

Beacon ARS and PM time differences.

  PRELIMINARY

The Beacon PM having a small TTS/sqrt(N), these gaussian distributions exhibit a width of 0.5 ns (the beacon PM does not contribute).

First plot : only the first ARS of each PM.

Second plot : both ARS on each PM

C. Colnard - 24/06/05

 

Environment

What's this? For slides (jpeg) For publications Description and comments
LCM headings - April 12 to June 21 Soon Heading data from compasses in each MILOM storey. See JPS' CERN presentation.

Schuller -June 05

Current measurement - April 15 to May 7 Soon Data from ADCP measureing sea water current speed and direction + picture of ADCP. See JPS' CERN presentation.

Schuller -June 05

Temperature measurement - April 13 to June 21 Soon Data obtained from the CTSeabird. See JPS' CERN presentation.

Schuller -June 05

Sound velocity - April 13 to June 21 Soon See JPS' CERN presentation.

Schuller -June 05

CStar (light transmissivity) Soon

CStar commercial device (picture and scheme). See JPS' CERN presentation.

Schuller -June 05

xCM Humidity

Soon

Humidity measured in all electronic modules. The effect of warming-up can be seen (detector is switched off during night and week-end). The measured humidity indicates that there are no water leak.

First plot : up to may 22

Second plot : one more month but SCM humidity is not measured.

Schuller -June 05

Bioluminescence : baseline and burst fraction Soon The burst fraction is the time ratio during which the counting rate exceeds the baseline by more than 20% (Note that this fraction might be underestimated if the counting rate exceeds what can be handled by the DAQ).

Stéphanie Escoffier

 

Acoustics

What's this? For slides (jpeg) For publications Description and comments
MILOM acoustics - principle scheme

ppt version

Soon Carr/Bertin - 09/06/05
Acoustic distance between two points on the MILOM   Acoustic distance between two points on the MILOM : RxTx module on the BSS and the Rx module in the first storey.

First plot : The variations from day to day are believed to be due to a lack of certain calibrations and storey rotation corrections in the present analysis.

Second plot : histogram of acoustic measurement between the two fixed points in the MILOM (from previous plot). Here an average position is calculated for each day and the difference is taken to this average.

Bertin/Niess

Acoustic distance measurement between the MILOM base and the autonomous transponder line   Acoustic distance measurement between the MILOM base and the autonomous transponder line (separated by 84 metres).

Bertin/Niess

Acoustic positionning pinger seen by the so-called spy-hydrophone.   This figure illustrates one of the GENISEA acoustic positionning pinger (those that are used for our acoustic positionning) detected by the spy-hydrophone.

On the top plot, the emitted signal is seen (the "ping"). It is a 51kHz wave front lasting 1 ms. The bottom plot shows a spectrogram as obtained from the spy-hydrophone. The signal is visible at t = 439-440 ms.

Bertin/Niess

Author : Thierry Stolarczyk