TELL1 high rate tests
@ Birmingham
Karim Massri
University of Birmingham
[email protected]
CEDAR WG Meeting – CERN – 26/03/2012
Outline

Introduction

Experimental setup



Special requirements for the random rate (RaR)
tests

RaR tests: components & TELL1 input

Adjusting the setup to get regular rate (ReR)
signals
Results

ReR & RaR results with TDCB clock @ 40 MHz

ReR & RaR results with TDCB clock @ 80 MHz
Conclusions
26/03/2012
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Introduction
High rate tests motivation:
Current estimated rate on each PMT of the CEDAR ~ 5 MHz
Electronics inefficiency study needed to choose the most
suitable number of PMTs
Particular remarks:

TDCB v5 has been used (previously v2)

Single channel study

TDCB clock initially @ 40 MHz, then → 80 MHz
Increasing the clock frequency means increasing the speed of the data reading from the TDCB buffer!
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Experimental setup
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Experimental setup
Special requirements for RaR tests


on the source:

Source of Poissonian-distributed pulses

Source must work at high rates (~MHz)

Frequency must be adjustable
on the data acquisition:
26/03/2012

The number of input pulses must be known

All the pulses must be sent while TELL1 is acquiring
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Experimental setup
RaR tests: components
Black Box
PMT
LED
preAmp
+
NINO
Light filter
2ch pulse generator
Scaler: ORTEC 974
4 channels
100% efficient up to 92 MHz
TDC board (v5)
TELL1
TRIGGER
Coincidence
Attenuator (31 db)
NIM to TTL
converter
CAEN 16ch
Low Threshold
discriminator
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Karim Massri – CEDAR WG Meeting –
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Experimental setup
RaR tests: TELL1 input
Black Box
PMT
LED
preAmp
+
NINO
Light filter
2ch pulse generator
To the LED: DC voltage
with adjustable amplitude
→ variable frequency!
(from 0 up to 50 MHz!)
TELL1
TRIGGER
To the NIM modules:
5µs long NIM pulse @100Hz
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TELL1 time
window = 20 µs
Coincidence
Attenuator (31 db)
Current firmware can handle no
more than 256 words per trigger!
TDC board (v5)
NIM to TTL
converter
CAEN 16ch
Low Threshold
discriminator
Karim Massri – CEDAR WG Meeting –
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Experimental setup
RaR tests: TELL1 input
Some more details about the input...
NINO input (after the preAmp):
Amplitude ~ 120 mV
Width ~ 8 ns
NB: the signal is
extremely regular!
(attenuated NIM signal)
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Karim Massri – CEDAR WG Meeting –
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Experimental setup
ReR tests: adjusting the RaR setup..
LED can't be used
to generate ReR
because it doesn't
Box
respond withBlack
a regular
light pulse!
PMT
LED
preAmp
+
NINO
Light filter
2ch pulse generator
Scaler: ORTEC 974
4 channels
100% efficient up to 92 MHz
TDC board (v5)
TELL1
TRIGGER
Coincidence
Attenuator (31 db)
NIM to TTL
converter
CAEN 16ch
Low Threshold
discriminator
26/03/2012
Karim Massri – CEDAR WG Meeting –
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Experimental setup
ReR tests: TELL1 input
Black Box
PMT
LED
preAmp
+
NINO
Light filter
2ch pulse generator
To the Low Th Discriminator:
Amplitude: 25 mV
Width ~5 ns
variable frequency (0200 MHz)
TELL1
TRIGGER
To the NIM modules:
5µs long NIM pulse @100Hz
26/03/2012
TELL1 time
window = 20 µs
Coincidence
Attenuator (31 db)
Current firmware can handle no
more than 256 words per trigger!
TDC board (v5)
NIM to TTL
converter
CAEN 16ch
Low Threshold
discriminator
Karim Massri – CEDAR WG Meeting –
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Experimental setup
Upgrading @ 80 MHz..

Current TELL1 firmware version: v132 (from Pisa)

Current TDCB firmware version: v5 (from Pisa)

TELL1 firmware @ 80 MHz: v136 (from S.Venditti)

TDCB firmware @ 80 MHz: v6 (from S.Venditti)
TDCB firmware upgrade via JAM (thanks to B.Angelucci!)
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Experimental setup
Data taking procedure

Set the frequency (RaR: adjusting the LED voltage)

Enable the scaler, start TELL1 acquisition

Turn on the trigger pulse from the generator

Wait until a certain number of counts has been reached

Turn off the trigger pulse

Stop scaler, end TELL1 acquisition
17 + 24 (RaR + ReR) runs / clock frequency (40MHz or 80MHz)
each one for a different frequency (~1MHz to ~15 MHz)
~20000 pulses have been sent to the TELL1 during each run
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Results
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TELL1 high rate tests
ReR tests @ 40MHz: inefficiency
TDCB v2 (December tests)
VS
TDCB v5
Trailing losses
due to extra leadings
No more event losses
@ ~ 5 MHz
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Up to 11 MHz
NO leading losses!
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TELL1 high rate tests
RaR tests: TELL1 output
Leading-to-leading Δt distribution measured by the TELL1
NO leading losses up to 11 MHz
→Fit with exponential for t>100ns → Mean frequency measured from slope
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TELL1 high rate tests
RaR tests @ 40MHz: inefficiency
TDCB v2 (December tests)
VS
TDCB v5
v5 looks slightly better!
26/03/2012
Karim Massri – CEDAR WG Meeting –
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TELL1 high rate tests
ReR tests @ 80MHz: inefficiency
TDCB v5 @ 40 MHz
VS
TDCB v5 @ 80 MHz
~ same inefficiency
at double rate!
26/03/2012
Karim Massri – CEDAR WG Meeting –
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TELL1 high rate tests
RaR tests @ 80MHz: inefficiency
TDCB v5 @ 40 MHz
VS
TDCB v5 @ 80 MHz
~ same inefficiency
at double rate!
26/03/2012
Karim Massri – CEDAR WG Meeting –
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TELL1 high rate tests
RaR tests @ 80MHz: inefficiency
TDCB v5 @ 40 MHz
VS
TDCB v5 @ 80 MHz
`
4% @ 5MHz
(instead of ~16%)
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Conclusions
TDCB v5 has been set and is now working @ Bham
(thanks to B.Angelucci!)

TDCB v2 <-> TDCB v5
TDCB v5 results slightly better (@ 40 MHz)

TDCB v5 @ 80 MHz (thanks to S.Venditti!)
wrt results @ 40 MHz ~ same inefficiency at double
rate (as expected) for both ReR and RaR
TDCB clock @ 80 MHz looks really promising!
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