Towards Electronics for a Long Baseline Neutrino Detector

1
Towards Electronics for a Long Baseline
Neutrino Detector
?

• Alfons Weber
• STFC University of Oxford

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Issues

• Introduction
• State of the Art
• MINOS/OPERA
• NOVA
• T2K/MINERVA
• Requirements
• physics
• photo detectors
• RD needs

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Introduction

• There are N Detectors
• At least 2N different electronics have been used
  to read them out
• No unique solution
• Solutions have been adapted from existing ASICS
• driven by cost, timescale, physics.
• not ideal
• But get the job done

4
Tensions

• Near Detectors
• high rate
• beam synchronisation
• limited channel count
• Far Detectors
• low rate
• no beam signal available
• huge channel count
• Performance
• high dynamic range, precise timestamps
• 100 lifetime
• low cost

5
What the following is about

• Electronics, need to integrate with
• DAQ
• photo detectors
• Photo-detectors
• PMT, APD, MPPC
• DAQ
• PCs?
• Detector
• scintillator with WLS fibre
• large PMT arrays?

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Solution MINOS ND
Input current
8-bit FADC value
Analog Voltage
QIE
FADC
FIFO
3 bit range code 2 bit CAP-ID code
CAP-ID QIE has 4 copies of current
divider/integrator ? 4 capacitor IDs
Every channel in the detector (9240) produces,
every 18.87 nsec FADC, RANGE, CAP-ID 1.4fC
lowest count sensitivity, 16-bit effective
dynamic range
QIE output voltage
Input charge

• Based on existing QIE ASIC
• dead-timeless for up to 20 µsec (spill)

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Solution MINOS ND (II)
Timing System
8 MASTER crates
44 MINDER crates
Front End (MINDER/MENUS)
Readout (MASTER)
Data Acquisition
Analogue PMT Pulse
Fast readout of digital data in response to
trigger
PVIC Transfers to PCs
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Solution MINOS FD/OPERA

• MINOS developed an ASIC chip for PMT readout with
  IDEAS
• 32 channels VA32_HDR11
• shaping
• amplification
• sample hold
• output driver to ADC
• Excellent product
• fast shaping 500 nsec
• noise lt 2 fC
• lineargt 20 pC
• 6 ASICs multiplexed onto 1 ADC

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Solution MINOS FD (system)

• Timing System
• Absolute time from GPS(?tabs 200 nsec)
• optical distribute along large detector (?trel
  4 nsec)

• Trigger-less DAQ system
• ASIC close to PMT
• ADC in VME crate
• fast PVIC-bus to PC trigger farm
• search for hits correlated in space and time

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Solution T2K/280m MINERVA
Spill Structure
2-3.53s
2-3.53s
Bunch Structure
Chip Time Structure
integration
reset

• 8 (15) batches
• Separated by 540 (241) nsec
• charge integrated in batches

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TRIP-t Front-end architecture
preamp
gain adjust 1,2,3,8
very simplified neglecting features not
relevant to ND280 operation
integrate/reset
Qin
analogue pipeline
1pF
3pF
discriminator
x10
gain 1 or 4
disc. O/P
Vth
reset

• only preamp gain affects signal feeding
  discriminator
• no fine control (x1 or x4)
• discriminator threshold Vth
• common to all channels on chip
• analogue bias settings
• gain, Vth, etc.
• programmable via serial interface

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Solution T2K (System Overview)
SiPM0
SiPM63
SiPM0
SiPM63
SiPM0
SiPM63



TFB0
TFB1
TFB47

TPS
Trigger Primitives
Power distribution
Clk trg
data
RMM0
CTM
Cosmic trigger
Gigabit/Ethernet
Clk trg
Clk trg
AcronymsTFB TRIP-t front-end boardRMM r/o
merger moduleCTM global trigger
moduleMCM master clock moduleSCM slave clock
moduleTPS TRIP-t power supplyFPN front-end
proc. node (PC)
Gigabit/Ethernet
MCM
SCM
FPN
Clk trg
Special trigger
GPS 1Hz/100MHz
(Acc. RF)
Gigabit/Ethernet
Spill trig
Gigabit/Ethernet
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Solution NOvA
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Common Thread

• Different solutions for near and far detectors
• developed around different existing ASICs
• heavy use of FPGAs
• huge variation in cost
• 20 - 300 per channel
• DAQ and electronics cant be developed
  independently
• later solutions move towards commercial back ends

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Requirements

• high QE photo detectors
• bigger detectors ? cheaper
• low noise electronics
• low readout thresholds ? bigger detectors
• dynamic range
• limited? 11000
• Timing
• O(1nsec)
• low trigger threshold
• low and high rate environment

?
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Requirements (II)

• Will take a long time for community to settle on
• detector
• photo detector
• requirements
• Try to develop multi-purpose ASIC
• test beam
• near detector
• external trigger, limited lifetime
• far detector
• cheap, scalable, 100 lifetime, self-triggering

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Ingredients

• ADC
• 11000
• TDC
• 1 nsec
• Trigger
• local/global
• clock distribution
• cheap HV supply
• 30-1000 V
• monitoring
• commercial interfaces

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The Pass

• Resume
• Performance is not leading edge
• Cost is main driving factor
• multi purpose device
• Work needed
• requirements capture
• design multi-purpose readout system
• Electronics
• DAQ
• Develop ASIC
• develop test system

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Who and Where?

• Who is driving this?
• which community
• physicists vs. electronics engineers
• Where can the work be done?
• major labs
• Universities
• Has to be user driven.
• Many questions, few answers.