UK Liquid Argon Initiative
Phil Lightfoot, Kostas Mavrokoridis, Neil Spooner
(University of Sheffield)
Gary Barker, Yorck Ramachers
(University of Warwick)
Manchester Seminar 10/12/2008
Y. Ramachers
Large Argon Detector
Motivations
• Neutrino beam physics (upgraded JPARC
beam, beta-beam facility, ν-factory)
– Precision mixing parameters
– Leptonic CP-violation
– Neutrino mass hierarchy
• Neutrino Astrophysics
• Proton Decay Search
• Geo-neutrinos
Manchester Seminar 10/12/2008
Y. Ramachers
Introduction
The use of liquid argon for calorimetry and more
recently for 3-D imaging with bubble-chamber
precision is now a mature technology [S.Amerio et al,
●
NIM A527 (2004) 329]
Next generation LAr neutrino detectors – vigorous
programmes in Europe and USA
● The Sheffield and Warwick groups believe the time
is right to build on what is known and kick-start a UK
R&D initiative in LAr
●
Manchester Seminar 10/12/2008
Y. Ramachers
Liquid Argon Detector
Charged particle traversing LAr:
• Ionisation: We=23.6 eV, 6000 electrons/mm for
a m.i.p.
• Scintillation: Wγ=19.5 eV, UV line at λ=128nm
or 9.7 eV → largely transparent 5000
photons/mm per m.i.p.
• Some Cherenkov light
High granularity sampling 0.02 X0 = 3 mm
Tracking capability combined with timing
provides true 3D imaging
Possibility of precision dE/dx
Also a total absorption calorimeter capable of
measuring neutrino energy to σE/E =10% or
better.
(A. Rubbia NuFact’05)
Sheffield/Warwick Strategy
Pick the best from existing concepts for each detector element
(1) Condensed detection medium
(2) Modular detection volumes
(3) Robust = Amplified signal operation
(4) Affordable read-out electronics
Concept for a homogeneous tracking calorimeter based on
Liquid (or Solid) Argon using planar, optical tracking read-out
Manchester Seminar 10/12/2008
Y. Ramachers
Research programme towards a
100 kton LAr experiment
Main cost factor:
Readout electronics
Basic LAr module
technology, affordability,
scalability → prototype
LAr-specific MCsimulation+specific
Data Analysis code
Manchester Seminar 10/12/2008
Component tests
for optical tracking
and calorimetry
Test-beam data at
CERN for LAr
proposal
Y. Ramachers
Concept
Imaging plane for tracking:
(2) Image amplification
by TGEM
Module
LAr Drift
+ Calorimetry
volume (1)
Drift length O(m),
to be optimised
Manchester Seminar 10/12/2008
1m2
(3) Sparse SiPM array
for image acquisition
Y. Ramachers
Concept
(1) Argon volume:
(a) Operation in condensed Argon = Homogeneity
(b) Trigger and calorimetry from plain Argon volume scintillation
(c) Purity requirements down = cost down → shorter drift distance
(d) Shorter drift = more readout-planes = higher cost
(e) Compromise on the order of one to a few meter – Find out!
Need to build a prototype – funding required!
Manchester Seminar 10/12/2008
Y. Ramachers
Concept
(2) and (3): Optical read-out with Amplification in Liquid:
New technique using known elements!
(3) SiPM operation at 77K in liquid demonstrated extensively:
P.K. Lightfoot et al., JINST 3 (2008) P10001
(2) TGEM amplification with SiPM read-out in liquid
demonstrated in detail (from gas to liquid):
P.K. Lightfoot et al., submitted to JINST
Manchester Seminar 10/12/2008
Y. Ramachers
Concept work in progress
• Facilities at Sheffield and Warwick
• Experimental program:
Purity control
➢ Double TGEM amplification
➢ Alternative SiPM's and photosensors
➢ Measurements with arrays → spatial resolution,
check for simulations
➢ Solid Argon test
➢ Cold electronics
➢
Manchester Seminar 10/12/2008
Y. Ramachers
Research programme towards a
100 kton LAr experiment
Main cost factor:
Readout electronics
Basic LAr module
technology, affordability,
scalability → prototype
LAr-specific MCsimulation+specific
Data Analysis code
Manchester Seminar 10/12/2008
Component tests
for optical tracking
and calorimetry
Test-beam data at
CERN for LAr
proposal
Y. Ramachers
Read-out Challenges
➔
➔
Expected to dominate total cost of large-scale LAr expt.
Recent estimates: Euro 60 `wire to computer’ MODULAr
(arXiv:0704.1422) ; Euro 50/channel ArDM (A. Rubbia,CHIPP’06)
Baseline concept:
➔
SiPM array 20x20 as imaging 'camera' per m2
➔ Strip-readout = 20+20 channels
➔ Target Cost: less than £20/channel readout
➔ SiPM low-cost elements now, in 10 years even less
Manchester Seminar 10/12/2008
Y. Ramachers
Read-out Challenges
Baseline Concept is work in progress:
Tested successfully circuit design for cold FE-electronics
➔ Components on board chosen for ease of mass production
➔ Current cost £10/item; no mass-production
➔ System-tests successful at room temp. (4x4 array)
next in LAr
➔ Total cost per channel decreases due to strip readout
4x4 array: 8*£10 for 16 channel = £5 / channel
➔
Manchester Seminar 10/12/2008
Y. Ramachers
Read-out Challenges
16 Photodiodes as detector array
Characteristics Mark I:
• Clock rate 10 MHz
• Dynamic range 25
• 8 bit resolution
• Less than 1 W power
per item
• Gain 50, source follower
preamp.
• No dead-time, totally
active
• Lots of head-room for
improvements
Manchester Seminar 10/12/2008
Y. Ramachers
Preamp+digitizer board
Research programme towards a
100 kton LAr experiment
Main cost factor:
Readout electronics
Basic LAr module
technology, affordability,
scalability → prototype
LAr-specific MCsimulation+specific
Data Analysis code
Manchester Seminar 10/12/2008
Component tests
for optical tracking
and calorimetry
Test-beam data at
CERN for LAr
proposal
Y. Ramachers
Signal Challenge
Long signal tracks mixed with detailed short track structures
'Typical' νμ event (15 GeV) in LAr
B. Morgan (Warwick), M. Robinson (Sheffield):
Full Geant4 sim for LAr detector working
Manchester Seminar 10/12/2008
Y. Ramachers
Signal Challenge 2
How to make the most of it ?
Requirements:
• spatial resolution order mm
for high PID efficiency (Rare events)
• Large detection volume for
• track containment, calorimetry, event rate
Manchester Seminar 10/12/2008
Y. Ramachers
Software framework task
MC-data
input
Monte-Carlo:
Event-generation
to charge drift
Manchester Seminar 10/12/2008
Data Analysis:
Bubble-chamber
track-type data
Detector Design
link
Y. Ramachers
Real-data input;
calibration
Prototype
construction
Software Status
Monte-Carlo effort with GEANT4:
➔ Event-generation using GENIE
➔ Flexible geometry using GMDL
➔ Decision on I/O data format pending
➔ Event visualiser working with GUI
➔ Planned extension to GEANT 'very low energy EM'
for electron drift and fluorescence avalanche in TGEM
in LAr(!) → not implemented yet in GEANT4
Data Analysis effort:
➔ Survey of existing solutions
➔ Unresolved task, highly non-trivial for
showers with bubble-chamber-like resolution
Manchester Seminar 10/12/2008
Y. Ramachers
Research programme towards a
100 kton LAr experiment
Main cost factor:
Readout electronics
Basic LAr module
technology, affordability,
scalability → prototype
LAr-specific MCsimulation+specific
Data Analysis code
Manchester Seminar 10/12/2008
Component tests
for optical tracking
and calorimetry
Test-beam data at
CERN for LAr
proposal
Y. Ramachers
Gallery
LAr setup at
Sheffield
Manchester Seminar 10/12/2008
Y. Ramachers
Gallery
LAr test
cell at
Sheffield
Manchester Seminar 10/12/2008
Y. Ramachers
Gallery
SenSL SiPM
example
Dark count rate with temperature
Manchester Seminar 10/12/2008
Gain as function of SiPM bias
Y. Ramachers
Gallery
TGEM: drilled holes in standard PCB – simple, reproducible, cheap
Sheffield TGEM
Warwick TGEM
Many variations possible and available in hole diam./pitch/thickness
Manchester Seminar 10/12/2008
Y. Ramachers
Charge gain from the cold gas phase of a double phase argon system
Charge gain spectrum
from Fe-55
Charge gain versus
drift field
Charge gain generated from a TGEM
at a constant 2.5KV/cm drift field
Electroluminescence from the cold gas phase of a double phase argon system
Secondary scintillation
spectrum from Fe-55
Secondary scintillation
versus drift field
Secondary scintillation generated
within a TGEM at a constant
2.5KV/cm drift field
Electroluminescence from liquid argon
Secondary scintillation
spectrum from Fe-55
Secondary scintillation
versus drift field
Secondary scintillation generated
within a TGEM at a constant
2.5KV/cm drift field
Conclusion LAr Initiative
➔
New technology for large volume LAr detector
development demonstrated
Particle tracker concept in Liquid Argon with
optical readout shown in 2 recent publications
➔ High S/N ratio and O(mm) spatial resolution
expected with optimised prototype (TGEM, SiPM
array, readout, etc)
➔ Scalable, robust and affordable technology
➔
➔
➔
Work in progress: Monte-Carlo, Data Analysis
FE-readout, concept tests
Of interest for NF/T2K detector efforts but need
funding for a prototype – Work in progress!
Manchester Seminar 10/12/2008
Y. Ramachers