tdc test beam data analysis
DESCRIPTION
TDC test beam data analysis. B. Angelucci Università di Pisa & INFN Pisa 01/04/2009. Introduction Hit distribution & noisy channels Missed hits in algo A & B PMT time resolution. ~25 cables. ~400 PMs. TELL1. TDCB. NINO CARDS. TDCB. TDCB. 1 Gb channel. PC & STORAGE. TDCB. - PowerPoint PPT PresentationTRANSCRIPT
TDC test beam data analysisTDC test beam data analysisB. AngelucciB. Angelucci
Università di Pisa & INFN PisaUniversità di Pisa & INFN Pisa
01/04/200901/04/2009• Introduction
• Hit distribution & noisy channels
• Missed hits in algo A & B
• PMT time resolution
Layout of 400PMT RICH Prototype test
TELL1
TDCB
TDCB
TDCB
TDCB GBE
PC &
STORAGE
NIN
O
CA
RD
S
Laser Ext trigger
~400 PMs
~25 cables
1 Gb channel
• Test with 400 PMs
• Laser and defocusing lens, ~30PMT fire each laser pulse
• Variable frequency (~Hz - ~MHz )
• Only one GBE output channel (max 1GBit/s)
• ~2% channels masked
Setup
channel channel
ch91
ch76
10 kHz 100 kHz
Noisy channels
Evidence of a difference between 10kHz and 100 kHz runs, for some channels (33, 42, 63, 69, 76, 91, 111, 137, 139, 155,
159, 169, 177, 179, 222, 258, 396, 417, 424)
Noisy channels
window of absolute time ~20s
Events all channels
channel 91
channel 90
Noisy channels
Events all channels
channel 91
channel 90
100us
Noise independent from events’ rate: more relevant in 10kHz runs
Missed hits in Algo A
10 kHz 100 kHz
Number of words per event
Number of words per event
• It is expected only an even number of words (leading & trailing edge)
• From data: uniform distribution (odd/even) in 10kHz runs, even predominance in 100kHz runs
Missed hits in Algo A
100 kHzDifference between number of trailing and leading per event for 100kHz runs
•The peak at dTL=0 indicates the predominance of an even number of words
• An odd |dTL| means an odd number of words
• dTL≠0 shows the presence of unpaired leading or trailing
30 leading 26 trailing
3 trailing from next event
Missed hits in Algo A
120 clk edges readout window
adjustable offset
Algo A scheme
Example of event in which dTL= -4
• The leak of trailing words is partially recovered from next event
ALGO A 10kHz
9% 1%
90%
good events
leading recovered
leading not justif ied
ALGO A 10kHz
15%
49%
36% good events
trailing recovered
trailing not justif ied
ALGO A 100kHz
32%
7%61%
good events
leading recovered
leading not justif ied
ALGO A 100kHz
43%
44%
13%
good events
trailing recovered
trailing not justif ied
Missed hits in Algo A
• Good events means no unpaired leading or trailing
• Not justified means not totally recovered
• Under analysis: debugging using pattern generator in progress
Missed hits in Algo B
10 kHz 100 kHz
Number of words per event
Number of words per event
trigger
Readout window
data flux in LB
Wait trigger on data
Algo B scheme
Missed hits in Algo B
• Good events means no unpaired leading or trailing
• Not justified means not totally recovered
ALGO B 10kHz
13%
72%
15%good events
leading recovered
leading not justif ied
ALGO B 10kHz
6% 5%
89%
good events
trailing recovered
trailing not justif ied
ALGO B 100kHz
40%
50%
10%
good events
leading recovered
leading not justif ied
ALGO B 100kHz
22%
8%
70%
good events
trailing recovered
trailing not justif ied
• Under analysis: debugging using pattern generator in progress
Differences Trailing time – Leading time
<tT – tL> for each channel σ[tT – tL] for each channel
threshold
tL tT
The difference tT-tL is rather proportional to signal’s amplitude
Resolution (ref ch14)
Offset <∆t(chx-ch14)>
for each channel
Raw resolution
for each channel
Offset and raw resolution: analizing the time difference ∆t(chx-ch14) for each event with both chx and ch14
Slewing correction for time resolution
∆t(ch31-ch14) vs (tT – tL)ch31 for each event
mean of each binx content
fit function
(2nd degree)
Raw & corrected resolutions
∆t(ch31-ch14) raw ∆t(ch31-ch14) corrected
σraw ~ 540 ps σcorr ~ 200 ps
A detailed analysis of test beam data has been presented
Comparison between 10kHz and 100kHz runs points out the presence of ~5% noisy channels (due to front-end electronics)
Most of the events show no more than one lost hit over ~ 60 at the edges of the readout window. Probable bug in the firmware under investigation
Single photo-electron time resolution of PMTs in fair agreement with measurements with CAEN TDCs (<250ps)
Next step: systematic measurements using fast and high resolution pattern generator
Conclusions