Original code from Iacopo Vivarelli' for time differences, Dskew constants...

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All runs taken till December 17 have been analysed. New files (December 17) for DSkew and timing constants available. Switched to Tfit for the estimate of the position of the pulse (previously using sample weighting method).

1) Time differences plots

For run 60727 (good run) the time difference plots time in pmt_i - time in pmt_1 look like below. Note that PMT 44 is not connected.

• 60727_LBA51.gif:
  

2) Dskew constants and timing corrections

Here is the list of LED runs used for each module to determine the timing constants. For each module it is the latest good run. Good run means that the pulse shapes, time difference and DSkew versus PMT number look OK.

LBA17	61432
LBA19	61877
LBA20	61877
LBA30	61434
LBA31	61434
LBA33	61437
LBA35	61437
LBA36	61437
LBA37	61877
LBA38	61877
LBA40	61877
LBA41	61877
LBA42	61877
LBA43	61877
LBA44	61877
LBA45	61877
LBA46	61877
LBA47	61670
LBA48	61877
LBA49	61877
LBA50	61877
LBA51	61877
LBA52	61877
LBA53	61877
LBA54	61877
LBA55	61463
LBA56	61463
LBA57	61465
LBA58	61465
LBA59	61465
LBA60	61465
LBC13	61412
LBC14	61412
LBC15	61412
LBC16	61412
LBC17	61031
LBC19	61877
LBC20	61877
LBC41	61877
LBC42	61877
LBC43	61877
LBC44	61877
LBC45	61877
LBC46	60220
LBC47	61419
LBC48	61877
LBC49	61877
LBC50	61877
LBC51	61877
LBC52	61877
LBC53	61423
LBC54	61877
LBC55	61423
LBC56	61423
LBC57	61425
LBC58	61425
LBC59	61425

The latest DSkew constants are available in the file:

• DSkewSummaryTable-06-12-17.dat: DSkewSummaryTable-06-12-17.dat

And the corresponding per pmt timing constants are in:

• LedCorrSummaryTable-06-12-17.dat: LedCorrSummaryTable-06-12-17.dat

3) Time difference vs PMT number

Plots of t_{i} - t_{1} vs PMT number i look usually like this (note the group of 6 PMTs, i.e. per digitizer)

• TdiffVsPMT_LBA45_60726.gif:
  

4) Pulse shapes

* LED_60725_LBA44_PMT1_pulse_shape.jpg:

5) Problems with fibers

a) Non connected fibers

Typical symptom of one missing fiber connection:

• PMT_37_48.gif:
  

As of december 17, non connected fibers were found in:

b) Low light amplitude

We can look at the amplitude of the pulse versus the PMT number to spot for fibers with large attenuation. For the moment it does not seem to be a problem. It will have to be investigated further when the laser system is in use.

Below this plot look just fine, the even and odd PMT do not get the light from the same fibers and we can also see two populations of pulse amplitude.

• AmplitudeVsPMT_LBA45_60756.gif:
  

Now on the plot below one can see the PMT 27 has abnormally low response, which might mean a problem with the corresponding laser fiber.

• AmplitudeVsPMT_LBA47_60756.gif:
  

c) Time shift between odd and even fibers.

On the following plot we can see that there is an overal time shift between odd and even fibers. This is due to the introduction of different LEDs, with different electronic, so the time between pulse is sent to the LED and the LED sends light there is a delay. Dskew can still be derived by correcting for this offset.

• timeDiffvsPMT_61524_LBA45.gif:
  

This effect is corrected for

7) Overall status

• LED-status-06-12-18.png:
  

• Status of LED timing constants on 06-12-10.png:
  

• Previous status (October 06):
  

8) Modules for which we need to take data AGAIN

See the status plot!

-- ChristopheClement - 31 Jul 2006 -- ChristopheClement - 14 Aug 2006 -- ChristopheClement - 22 Sep 2006 -- ChristopheClement - 02 Nov 2006 -- ChristopheClement - 17 Dec 2006

• LED-status-06-12-18.png: