Post on 22-Feb-2016
description
Update on time calibration with optical beacons
Collaboration MeetingRoma, 7-10 May 2012
Agustín Sánchez LosaIFIC (CSIC – Universitat de València)
Outline
• Reminder of the time calibration with OBs• Intraline calibration: T0s– Nothing new since CERN’12
• Interline calibration: Time offsets– Laser position and its impact in offsets
• Some order in the DB tables of T0s• To-Do List
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting 2
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting 3
Time calibration recipe:– Flash various OMs at the same time by an OB– Plot the distribution of hit arrival times for each ARS– Fit such distribution with a Gauss@Exponential function– Determine Tpeak , the time of the function peak– Plot Tpeak vs distance– Deviations from the straight line fit will be used as corrections to the T0s
F 2
F 3
F 4
F 5
F 6
F 7
F 8
F 9
F 10
F 1
Reminder of the time calibration
waterOBOM c
OMOBdttt ),(
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting 4
LED
LED
Laser
Reminder of the time calibration
• T0 in the same line• LED OB• Early-photon region
Intraline calibration
• time offsets between lines• Laser OB• Photo-electron level region
Interline calibration
IntralineT0s in the same line by means of the
LED OBs
57-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting
Nothing newsince CERN'12
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting
InterlineTime offsets between lines by means
of the Laser OB
6
Interline: Laser position impact on offsets
• Was detected the use of an incorrect position of the laser (Ciro’s curiosity fault)
• Laser offsets recomputed for all the periods (from Aug'09 to Dec'11)
• The impact in the laser offsets has been measured and estimated
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting 7
87-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting
L3
L4
L6
L5
L7
L10 L11 L12
L8
F 4
F 10
F 1
F 8
F 5
F 10
Early photonRegion
PhotoelectronLevel RegionF 10
F 3 - F 4F 8 - F 9
F 1
L1 L2 L9
L1 L2
L3 L4 L6L5
L7 L8 L10L9
L11 L12
LINES
OLD NEW MEASS.DIFF
1 -2,7 -3,3 -0,7
2 -2,8 -3,3 -0,7
3 0,2 -0,1 -0,4
4 -1,8 -2,1 -0,5
5 -3,4 -3,6 -0,3
6 -0,4 -0,6 -0,3
7 -0,5 -0,4 0,0
8 7,5 7,6 0,0
9 -0,2 0,1 0,2
10 -0,7 -0,4 0,2
11 4,0 4,6 0,5
12 0,7 1,3 0,5
ESTIM.DIFF
-0,6
-0,8
-0,4
-0,5
-0,3
-0,5
0,0
-0,1
0,3
0,0
0,5
0,5
Interline: Laser position impact on offsets
Interline: T0s tables in the DB
• Some order have been done in the T0s DB tables:– All official T0s LABEL field have a clear ordered #id– OFFICIAL value has a clear use:• OFFICIAL = 2 → Best T0s available without any interline offset added• OFFICIAL = 3 → Best T0s available with interline offset added (see
USER_COMMENT field explains which ones)– Now APP_START field is coherent for all the periods
– Sample SQL call:
7-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting 9
select version_id, label, app_start, user_comment, udate, official from antares.ars_t0 where official = 2 or official = 3
order by official, app_start desc
Interline: T0s tables in the DB• Sample SQL call:
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To-Do List
117-10 May 2012 Agustín Sánchez Losa – Roma Collaboration Meeting
• Intraline calibration by OB:– Compute intermediate T0s– Recompute old T0s with updated TVCs and study the
impact of using ones or another– Research & Improvement on intraline calibration:
Calibrate the first floors of each line, study the impact of a calibration with independent sections, Study unstable PMTs since HV tuning in Summer'10, etc.
• Interline calibration by OB:– Research & Improvement on interline calibration.
Thank youfor your attention