Barrel Jitter Analysis
Julien Labbé
Barrel P3C meeting, Thursday June 7th 2007
Principles
Software
Output
Summaries
Inspection
Problematic channels
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
1
Principles
Calibration waves
Error on CaliWave known : 
2 sources
Noise (irrelevant) :  N
Jitter (unknown) : 
N
J
df
dt
2
 
df 2
 = 
J
dt
2
2
N

J
y=y0  x
Linear fit
{
J =

J

2
vs
2
 
d f
d t


=
2 
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
2
Software
Create a root file with the following
histograms :
LArJitterMon/JitterSummaries
Entire detector and FT summaries
LArJitterMon/febJitterValues
LArJitterMon/febJitterErrors
FEB jitter/error per channel
LArJitterMon/chanProblemInspection
Details on dead channels (no jitter
calculated)
LArJitterMon/chanJitterInspection
Details on channels with high jitter
Can be runned with LArCaliWaveBuilder
Jitter histograms are in Wave rootFiles on
largh8
ATHENA
Maintained by Emanuel Rauter (from EC)
CaliWaveBuilder
Builds
waves
LArMonTools/
LArJitterMonTool
LArJitterMonTool
Builds
histograms
LArMonTools/rootMacro/
LArJitterMonitoring
LArJitterMonitoring
Builds graphs
on the fly
ROOT
Written by David Link (CERN Summer
Student)
Root GUI
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
3
LArJitterMonitoring Outpout : Jitter Summaries and Plots
By default :
Green = Good, jitter < 0.14 ns
Red = Warning, jitter > 0.14 ns
Barrel
summary
FT summary
Jitter values for all channels of a FEB
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
4
LArJitterMonitoring Outpout : Jitter Inspection
FEB channels' jitter
Waveshape
Derivative
Linear fit : error2 vs derivative2
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
5
LArJitterMonitoring Outpout : Problematic Channels
For dead channels doesn't
calculate jitter but plots
graph for study
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
6
Summary and Outook
Summary
JitterMonTool called in BP3C_Delay_Monitoring.py in the largh8
account
Jitter values are in Wave rootFiles
Jitter RootMacro plots
Detector/FT summary
FEB jitter values
Details on dead channels/channels with high jitter values
Outlook
Check jitter for all power supplied FT
Need to understand better the absolute jitter value (~ 0.050.1 ns) and fix properly the threshold for hight jitter (default :
0.14 ns)
Julien Labbé - Barrel Jitter Analysis - Barrel P3C meeting, Thursday June 7th 2007
7