A Brand new neutrino detector?SciBar?(2)

1
A Brand new neutrino detector?SciBar?(2)
- Readout Electronics -

• Y. Takubo (Osaka)

• Introduction
• Readout electronics
• Cosmic ray trigger modules
• Conclusion

2
SciBar detector

• 2.5 x 1.3 x 300 cm3 scintillator strips
• Extruded scintillator with WLS fiber readout
• 15000 channels
• Light yield
• 720p.e./MIP/cm (2 MeV)
• Requirement for p/p separation
• Dynamic rangegt10.6MIP(286p.e.)

EM calorimeter
Extruded scintillator (15t)
3m
3m
Stopping p
1.7m
Multi-anode PMT (64 ch.)
Wave-length shifting fiber
3
Detector Components
Timing distributor
DAQ board
Trigger board
AMT
64ch MAPMT
Front-end board
4
Requirement to readout electronics

• Large number of channel (15,000)
• compact photo-detector and circuit

• High sensitivity (MIP 7 20 p.e./1strip)
• Noise level lt l p.e. (0.08 pC)

• Large dynamic range (1 p.e. 300 p.e.) for
  proton energy reconstruction

• Fast trigger (Bunch identification)

• VA/TA front-end electronics
• DAQ board (VME)
• AMT, Timing distributor

5
Readout Electronics
VATA is used for MAPMT for the first time.
1.2ms
hold
? charge
VATA Chip
PMT signal
(Energy information)
(Timing information)
Front-end board
VA/TA chip
A front-end board has two VATA chips.
6
DAQ board

• DAQ board is custom module for SciBar readout.
• Control of VA readout sequence
• Setting of VA trigger threshold
• VA serial output is digitized by FADC (dynamic
  range 300 p.e.)
• 8 front-end board (512 ch) are connected to one
  DAQ board.

All channels (15,000) are read by only 28 DAQ
boards.
VME bus
Timing distributor
8 front-end boards(864ch)
16ch2 TA signal
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Timing Distributor
Daughter board
16ch NIM I/O
DAQ board
162ch LVDS/ECL Input
FPGA

• VME 6U module that distributes timing signals
  to DAQ boards through the bus.

• 4ch NIM I/O on main board 2 daughter boards

Daughter board
162 ch LVDS/ECL Input
16ch NIM I/O

• Flexible data processing is realized using FPGA.

8
AMT

• Develop as Atlas Muon TDC(AMT)
• VME 6U module
• Multi-hit TDC
• 64 channel in a module
• 100 usec full scale
• 0.78 nsec/count

64 TA signals
All TA signals (448 ch) are read by 8 AMTs
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Basic performance of VATA readout
TA threshold curve
Gain linearity
4000
600
3000
ADC cont
2000
Trigger efficiency ()
Noise hit
400
1000
0
20
40
Input charge (pC)
200
5 non-linearity lt 24pC(300p.e.)
0
Gain distribution (all channels)
40
80
20
60
TA threshold (mV)
TA threshold canbe set 0.4 p.e. without noise
hit.
entries
Gain 80count / pC 6count / p.e. lt Pedestal(
1.5count)
80
100
60
40
Gain (ADC count / pC)
10
Timing resolution
Cosmic ray event is used to estimate timing
resolution.
Timing resolution is estimated by comparing
timing of 2 channels.
Correction of light propagation time in a fiber
s 4.03 nsec
Timing resolution
TQ correction
s 1.84 nsec
4.03/v2
T(nsec)
2.85 nsec
Timing resolution 1.84/v2
1.30 nsec
15
0
-10
10
nsec
0
10
-10
0
nsec
-15
200
0
400
Q(ADC)
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Track direction ID by TOF
3 super-layer penetration
Track length 50.5 cm
T1
T3
Direction ID probability 89.3
z1
z8
10
0
-10
SdT (nsec)
12
Achieved performance

• 5 non-linearity at 300p.e.
• Noise level lt 1 p.e.
• sT 1.3 nsec

• p/p separation, momentum reconstruction
• Uniform hit efficiency
• Additional information for tracking
• Neutrino event identification from neutron B.G.

13
Trigger scheme
14
Cosmic ray trigger modules
Data taking cycle
beam
pedestal
LED
cosmic
Time
2.2 sec
Cosmic ray data is taken for the calibration in
the off-spill.
Trigger board is developed to take cosmic ray
event effectively in the off-spill time
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Logic for cosmic ray trigger
Identification of hit track
Make matching with two trigger signals
112 TA
Trigger Board
7 DAQ Board
Master trigger board
112 TA
Trigger Board
7 DAQ Board
Top side view
A half of the TA channels (224ch/448ch) are used
for cosmic ray trigger.
16
Trigger Board
Output 1ch
input 128 ch (168)
Output 16 ch
FPGA decide to make trigger signal.

• VME 9U module

• Front panel input 128 (168) ch LVDS/ECL

• Back plane output 16ch LVDS/ECL

• Using FPGA, trigger logic can be easily
  implemented for any combinations of 128 inputs.

17
Current status of cosmic ray event
Hit distribution
Current cosmic ray trigger takes all though going
muons
250
Angle distribution
Horizontal position(cm)
150
80
Zenith angle(degree)
0
0
80
160
Z(cm)
?
-80
250
80
-80
0
Vertical position(cm)
Azimuth angle (degree)
150
Horizontal line
New trigger design is prepared to get horizontal
events and uniform hit distribution.
0
80
160
Z(cm)
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Trigger Design
Requirement

• Horizontally through-going muons are taken for
  calibration effectively.
• Distribution of cosmic ray hits is uniform.
• TA signals are trigger board inputs.

Trigger design

• Trigger is generated, based on the hit pattern
  identification.

Preparing hit patterns, track pattern matching
them is selected.

• Track with less than 45 degree of zenith angle
  is taken.

19
Event display of cosmic ray event
Side View
Top View
µ
µ
20
Event display of stopping m event
Top
Side
e
e
µ
µ
21
Summary

• SciBar detector uses VATA readout system.
• It has 5 non-linearity at 300p.e., and its
  noise level is less than 1 p.e..That satisfies
  required performance.
• Trigger board is used for cosmic ray trigger, and
  upgrade trigger logic is prepared for effective
  data taking.
• All readout system is working well.

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Omake
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Principle of VATA readout
Pre-amp
Fast-shaper
TA
Slow-shaper
Hold_b
32ch VA serial output
outm
1.2ms
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Multi-anode PMT

• Hamamatsu H7546 type 64-channel PMT
• 2 x 2 mm2 pixel
• Bialkali photo-cathode
• Compact
• Low power lt 1000V, lt 0.5mA
• Gain 6 x 105
• Cross talk 3
• Gain uniformity 20 (RMS)
• Linearity 200 p.e. _at_ 6 x 105

Top view
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Scintillator WLS Fiber
Scintillator
1.8 mmf

• Size 1.32.5300 cm3
• Peak of emission spectrum 420 nm
• TiO2 reflector (white) 0.25 mm thick

300 cm
1.3 cm
2.5cm
Wave-length Shifting Fiber

• Kuraray
• Y11(200)MS 1.5mmf
• Multi-clad
• Attenuation length 3.6m
• Absorption peak 430nm
• Emission peak 476nm

Charged particle
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Achieved Performance Current Status of Cosmic
ray trigger
Achieved performance

• Decision time is 100 nsec.
• Single rate of one TA is about 100 Hz.
• Trigger rate is about 100 Hz.
• Data acquisition rate is about 20 Hz.

Current Status
We now use a trigger logic for the commissioning.
We make or signals of every other layer, and
make coincident with those of the top and side
separately. We make and signal of the top and
side.
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Estimation of direction ID
Track direction is identified by timing
information.
Top or Side view
T1
T1
T2
T2
forward
Tn
backward
SdT S (T2 - T1)
TopSide
If n gt 2,
n
n/2
SdT S (- STi STi )
i0
TopSide
in/21
z1
z8
SdT gt 0 forward direction
SdT lt 0 backward direction
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2 super-layer penetration
Track length 25.2 cm
T1
T2
Cosmic ray
Direction ID probability 72.5
z1
z8
10
0
-10
SdT (nsec)
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3 super-layer penetration
Track length 50.5 cm
T1
T3
Direction ID probability 89.3
z1
z8
10
0
-10
SdT (nsec)
30
Hit distribution of cosmic ray event
250
250
Vertical position(cm)
Horizontal position(cm)
150
150
0
0
80
160
80
160
Z(cm)
Z(cm)
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