Transcript Diapositiva 1 - IDEA project

Milano, 10/11/2006
Double Beta Decay in ILIAS-next
Andrea Giuliani
v
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Main objective
develop specific aspects of various detector
technologies (both classical and innovative)
aiming at improving the sensitivity in the
search for rare events
 ameliorate existing experiments
 set the bases for new projects
increase the value of the
infrastructures which
normally host these
searches, i.e. the
underground laboratories
impact on key aspects of
astroparticle physics:
 neutrino physics
 dark matter discovery and
identification
 rare event searches in general
Four Work Packages
WP1
Very low temperature
solid state detectors
WP2
Noble liquid and
gas detectors
WP3
Advanced semiconductor
detectors with active and passive
background control
WP4
Scintillation detectors
optimized for rare event search
WP1…
1.1 New scintillating crystals for Double Beta Decay and Dark
Matter searches
Objective: develop novel scintillating bolometers for rare event searches
Tasks:
(i) select compounds for scintillating crystals of potential interest for Double Beta
Decay and Dark Matter
(ii) characterize the light yield at low temperatures of the selected crystals
(iii) operate the crystals as bolometers with double read-out configuration
(iv) test preliminarily the background in the relevant energy regions
1.2 Single-photon light detectors operated at very low
temperatures
Objective: realize light detectors suitable to be operated in the 10-100 mK
range, to be used in dark matter search with very low threshold
scintillation+heat bolometers
(i) select the optimal materials for bolometric light detectors
(ii) develop phonon sensor technology for bolometric light detectors
(iii) study coating methods to widen the sensitive band
(iv) exploit the so-called "Luke effect" to approach single optical photon
sensitivity
1.3 Fast microcalorimeters for direct measurement of neutrino
mass
Objective: realize detectors at keV energies with time response in the
microsecond range in order to measure single beta decay with
minimization of pulse pile-up
(i) study of magnetic microcalorimeters
(ii) development of transition edge sensors
(iii) realization of kinetic inductance detectors
(iv) develop synergies with CMB and astrophysical X-ray detection techniques
… WP1
1.4 Macro-bolometers with event localization capability for
background identification
Objective: develop macrobolometers capable to identify alpha and beta
particles absorbed at the surface
(i) advanced study of pulse formation (heat, ionization and light channels)
(ii) optimization of thin film sensors sensitive to athermal phonons
(iii) events localization through pulse shape analysis (phonon and ionization),
and development of simulation tools
(iv) event localization by exploiting the dynamics of heat flow in composite
bolometers
1.5 Improvement of charge collection in heat+ionization
detectors
Objective : Improve the charge collection efficiency for surface events in
heat and ionization detectors
(i) advanced study of charge collection and charge trapping in semiconductors at
very low temperatures in low electric field
(ii) optimization of amorphous Ge and Si sublayers under the electrodes and
minimization of trapping at the surfaces
(iii) development of simulation tools
1.6 High energy resolution microcalorimeters operated in
medium – high magnetic fields
Objective: to operate a low-temperature high-energy-resolution calorimeter
in a few T magnetic field, in view of an advanced KATRIN’s detector system
(i) characterize phonon sensors in medium-high magnetic field, in particular of
NTD Ge and implanted Si thermistors, in terms of R-T behaviour and of electronphonon decoupling
(ii) realize a single pixel calorimetric detector operating in a few T magnetic field
(iii) study and design a dilution refrigerator able to host a low temperature
calorimeter in a few T field and suitable to be matched to the KATRIN’s main
spectrometer
WP2…
2.1 Advanced methods of charge readout
Objective: to develop and qualify advanced low background micro-pattern
charge readout technology for TPCs to be used in rare event search
Tasks:
(i) Technical comparison of state of the art in GEMs, LEMs and Micromegas
(ii) Optimization of position resolution and gain at low energies
(iii) Optimisation of quench gases and gas mixtures for single and two phase
operation
(iv) Development of improved electronics, HV and software including imaging
(v) Low background material selection
2.2 Advanced methods of light readout
Objective: to develop low background, UV sensitive, low temperature photon
sensors of large area for TPCs to be used in rare event search
Tasks:
(i) Technical comparison of state of the art in PMTs, Si-PMTs and APDs
(ii) Development of improved light collection - large area photocathodes, CsI
coatings, UV wavelength shifters, liquid-PMT coupling including flanges.
(iii) Development of fiducialisation and position sensitivity techniques
(iv) Optimisation for robustness and long-term, low noise operation in gas and liquid
(v) Low background material selection
…WP2…
2.3 Target medium purification and isotopic separation
Objective: to develop gas and liquid target materials with optimum low
background, isotopic, purity and optimum electron or photon transport
properties
Tasks:
(i) Production of "dead argon" (argon free of 39Ar)
(ii) Krypton, tritium and radon removal and control
(iii) Recirculation and pumping technology including cartridge purity
(iv) isotopic enrichment
2.4 Ionisation and scintillation processes at keV energies
Objective: to improve understanding of the fundamental processes of
particle interactions in gases and liquids at keV energies
Tasks:
(i) New measurements of quench factors at low energy using neutron beams
including systematic measurements for different elements, purity, temperature and
pressure using the same chambers and electronics
(ii) Cooperation with condensed matter community on relevant low energy
ionisation physics and new measurement techniques in Noble liquids and gases
(inc. Hitachi)
(iii) Improved understanding of non-statistical ionisation and scintillation fluctuations
…WP2
2.5 Event reconstruction and imaging
Objective: to establish improved software and techniques for reconstruction,
fiducialisation and imaging of events in TPCs
Tasks:
(i) Study of lateral and transverse diffusion, timing and position resolution in TPC
gases - influence on detector designs
(ii) Development of optimised event positioning concepts
(iii) Development of optimised track reconstruction procedures for low energy
ionisation events in gases for directional detectors
2.6 Advanced study of pulse shape properties of LAr scintillation
light
Objective: to develop improved pulse shape discrimination techniques for
particle discrimination methods in liquid argon applicable in dark matter
detection
Tasks:
(i) Study of the time distribution of scintillation photons in response to , ,  and
neutron radiation and its dependence on chemical impurities and on electrical
fields.
(ii) Development of optimized front-end and digital electronics for pulse shape
analysis purpose
(iii) Development of novel numerical analysis tools for discrimination of -, -, events and recoil events
2.7 Propagation of XUV photons in liquid argon
Objective: to study the propagation of 128 nm XUV scintillation photons in
liquid argon and to develop MC simulation tools for detector modelling
Tasks:
(i) Study of elastic and inelastic scattering of XUV photons in liquid argon and the
dependence on chemical trace impurities
(ii) Development of Monte Carlo tools for the simulation of XUV light propagation
including wavelength shifting processes to model the detector response of large
liquid argon detectors.
WP3…
3.1 Ultra-low background Ge array for material selection
Objective: development of an ultra-low background Ge detector array for
material assay at the 1 Bq/kg level in underground laboratories
Tasks:
(i) Simulation and optimization of geometry of array with passive and/or active
shielding system
(ii) Design, development and calibration of system
3.2 Electrode segmentation in Ge detectors for event
identification
Objective: to study the discrimination of multi-site from single-site events (i.e.
background events from double beta decay signal) using electrode
segmentation in low-background Ge detectors
Tasks:
(i) Study of the operation of segmented bare Ge detectors with low-background
contacts in liquid argon
(ii) Localization and event reconstruction using mirror charges
(iii) Comparison of background reduction factors of calibration data with MC
simulations
3.3 Novel liquid argon active veto system for Ge detectors
Objective: to study background suppression of bare Ge detectors submerged
in liquid argon by using the scintillation light of liquid argon. Detectors both
with segmented and unsegmented electrodes will be investigated
Tasks:
(i) Operation of bare Ge detectors in a liquid argon with scintillation light read out at
an underground laboratory
(ii) Development of full MC description of a LArGe hybrid detector system
(iii) Study of orthogonality of background reduction of segmentation and LAr active
veto
(iv) Study of LArGe system sensitivity for double beta decay and sample counting
…WP3…
3.4 Advanced pulse shape analysis in Ge and LArGe hybrid
detectors
Objective: exploit time structure of charge signals from Ge detectors and
LArGe hybrid detectors for event recognition and background reduction in
double beta decay
Task:
(i) Study of the time structures for various event classes in Ge (segmented,
unsegmented, coaxial, true-coaxial) and LArGe hybrid detectors
(ii) Modelling of characteristic time distribution of events in Ge detectors and
LArGe hybrid detectors including the scintillation signal for various event classes
and comparison with experimental data
3.5 Pixellization in CdZnTe detectors for particle identification
Objective: explore pixel pattern in CdZnTe semiconductor detectors to
identify different particles as active background reduction in double beta
decay
(i) Model various particles (alpha, betas and gamma) as well as double beta
decay events in pixellated CdZnTe detectors to explore their characteristic
features and optimise pixel size.
(ii) Study such a detector underground to prove the expected performance after
extensive calibration on the surface.
3.6 Advanced Pulse shape analysis in CPG CdZnTe
Objective: explore pulse shape of each of the two electrodes in coplanar
grid CdZnTe detectors for vertex determination and extension of events
Task:
(i) Develop readout of individual grids by modifying available preamplifier and
study pulse rise-times
(ii) Use high energy gamma sources for pair production as an approximation to
double beta events and low energy sources for point-like charge depositions.
…WP3
3.7 Performance of CdZnTe semiconductors in liquid
scintillator
Objective: run CdZnTe semiconductors with a minimum of material within a
Liquid Scintillator acting as an active veto for background reduction
Task:
(i) Find reasonable scintillators, materials and run a naked CdZnTe detector in it
WP4
4.1 Liquid scintillators for low energy neutrino detection
Objective: to improve the low background, the scintillation yield and
attenuation length of liquid scintillators
Tasks:
(i) Production of new liquid scintillators formulation highly doped with metallic
compounds
(ii) Improvement of the radiopurity level by removing noble gas radioactive isotopes
(iii) Optimisation of the chemical compatibility with other plastics including optical
fibers and plastic scintillators
(iv) Simulation of the light propagation
4.2 Solid organic scintillators
Objective: to improve the production and collection of the light, the
transparency and the stability of the plastic scintillators
Tasks:
(i) Development of scintillators polymer base
(ii) Study of new backlight reflectors for the scintillator wrapping
(iii) Simulation of the light propagation
4.3 High-efficiency low-radioactivity photomultipliers
Objective: to develop high quantum efficiency and very low radioactivity PMT
and to be able to survey the gain of the PMT with very high accuracy
Tasks:
(i) Development of new low background glasses and ceramics
(ii) Selection of radiopure PMT materials
(iii) Optimisation of photocathodes and dynodes characteristics for photoelectrons
production and collection
(iv) Development of PMT gain survey with very high precision
Budget considerations
Number of subtasks
Subtotals
WP1
6
720
WP2
7
840
WP3
7
840
WP4
3
360
Total
2760
Budget for each subtask
120