Date post: | 03-Jan-2016 |
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Configuration with ADC gives possibility to correct measured time on pulse height off-line.
=> better control than in case of CFD
Quartz bar start counter
4 pad MCP TDC
ADC
LeadingEdge Disc.
PiLas laser
Start Counter – resolution vs. light intensity
Before ADC correction After ADC correction
Raw TDC/ADC ADC correction ADC slices Resolution vs.Light intensity
Analysis procedure:
Start Counter – resolution vs. light intensity
Time resolution vs. number of electrons, Quartz bar start counterGate set to 30 ns (measurement from 12-16-2004)
10
100
1000
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00
ADC signal [photoelectrons]
Sig
ma
[ps]
Sigma (FWHM) - new data (narrow gate)
Narrower sigma - old data (wide gate)
1 over square root
~50 ps
~50 photons
Each point is sigma obtained from double Gaussian fit of TDC spectrum.
Quartz start counter in multiphoton mode
Pad
0P
ad
1P
ad
2P
ad
3
Light intensity: from 200 to 700 photons
=44 ps
=29.5 ps
=76 ps
=28.5 ps
0 1
2 3
The laser si not 100% centered
TDC spectrum Raw ADC/TDC Corrected ADC/TDC
Slot tests
Slot 2 Slot 3 Slot 4
Slot 5 Slot 6
All slots tested with the same set of Philips TDCs
Tested 320 pads in 5 slots. 301 pads were OK.
56 pads OK 60 pads OK 58 pads OK
64 pads OK 62 pads OK
Note: “pad” includes MCP, amplifier and CFD
Timing resolutions in single photon mode
Best [ps] Worst [ps] Average [ps] Median [ps]
Slot 2 181 393 253 230
Slot 3 194 419 250 237
Slot 4 157 416 259 264
Slot 5 164 385 221 211
Slot 6 168 353 228 211
Table of resolutions
Table of hit probabilitiesPilas frequency 1kHzSlot Hit probability* Multiple hits** DAQ [Hz]
2 1.8% 1 99
3 1.0% 2 109
4 5.8% 8 102
5 3.5% 4 102
6 0.6% 1 102
**number of pads hit by photons per event
MA
*hit probability for single pad
MC
PM
CP
MC
PM
CP
MA PMT connected to SLAC ADCs and Phillips TDSs
Phillips(common start)
SLAC(common stop)
Log
scale
Log
scale
Log
scale
Majority ofevents
System stability
TDC spectrum (the whole run)
Peak position asa function of time
The aim is to determine stability of channel delay calibrations over time. Discover systematic effects.
10 hours
Counts [-]
2.6
2 c
ou
nts
~0
.34
Example of online monitoring histograms
Hodoscope window
Cherenkov ring window
Histograms in the window:
•horizontal fingers•horizontal hit multiplicity•vertical fingers•vertical hit multiplicity•horizontal profile•vertical profile•raw hit map•corrected hit map
Data of any module in the system can be visualized online.
(including start counters, MAs and MCPs in the prototype and other)
(+ Timing windows)