8th Topical Seminar on Innovative Particle and Radiation Detectors Siena, 21 – 24 October 2002
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Transcript of 8th Topical Seminar on Innovative Particle and Radiation Detectors Siena, 21 – 24 October 2002
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8th Topical Seminar on Innovative Particle and Radiation Detectors
Siena, 21 – 24 October 2002
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SIENASIENA is located in Tuscany about 50km south of Florence
Ancient Etruscan settlement, became Roman colony under the name of Sena Julia
Its importance grew in Middle Ages until became a municipality in 12th century: flourished in XIV century
Frequent confrontations with neighbouring towns: taken over by Florence in 16th century
Still retains an authentic medieval atmosphere
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Piazza del Campo 14th century, is the heart of the city
Location of the ancient roman forum, boasts 14th century gothic buildings
Palazzo pubblico e Torre del mangia Fonte Gaia by Jacopo della QuerciaThe horse race (Palio) is held here, 2nd of July and 16th of AugustOf medieval origin, sees the 10 of the 17 contrade competing against each other: the winner gets the Palio (banner)
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The Dome,XIV century: one of the best roman-gothic architectural examplesMasterpieces by Nicola Pisano, Donatello,Pinturicchio
Floor consisting of 56 different mosaics, depicting sacred scenes, required more than 150 years to be completed
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High Energy High Energy Neutrino AstronomyNeutrino Astronomy
Christian Spiering, Siena, October 2002
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Physics Goals
A. High Energy Neutrino AstrophysicsWeakly interacting neutrinos reach us from very distant sources:
possible invaluable instrument for high-energy astrophysicspossible invaluable instrument for high-energy astrophysics B. Particle Physics
Magnetic Monopoles, Oscillations, Neutrino Mass ...
C. Others Supernova Bursts, CR composition,
Black Holes, ...
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Cosmic Rays
1 TeV
GZK cut-off
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Supernova shocksexpanding in
interstellar medium
Crab nebula
up to 1-10 PeV
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Active Galaxies: accretion disk and jets
VLA image of Cygnus A
up to 1020 eV
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log(
E2
Flu
x)
log(E/GeV)TeV PeV EeV
3 6 9
pp core AGN p blazar jet
Top-down
GRB (W&B)
WIMPsWIMPsOscillationsOscillations
UndergroundUnderground
UnderwaterUnderwaterRadio,AcousticRadio,Acoustic
Air showersAir showers
Microquasars etc.
GZK
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1 pp core AGN (Nellen)2 p core AGN Stecker & Salomon)3 p „maximum model“ (Mannheim et al.)4 p blazar jets (Mannh)5 p AGN (Rachen & Biermann)6 pp AGN (Mannheim)7 GRB (Waxman & Bahcall)8 TD (Sigl)9 GZK
Diffuse Fluxes: Predictions and Bounds
Mannheim & Learned,2000
MacroBaikalAmanda
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Detection Methodsand Projects
Detection by Air Showers
Underwater/Ice Cerenkov Telescopes
Acoustic Detection
Radio Detection
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Underwater/Ice Cerenkov Telescopes
4-string stage (1996)
Strings of widely spaced PMT put in deep water
AMANDA: Antarctic Muon And Neutrino Detector Array
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cascademuon
Cerenkov radiation in H2O : v0.75c, = tg-1[(n2 v2/c2-1)1/2] High-energy neutrinos through the earth may
interact and create muons which emit Cherenkov light
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1 km
2 km
SPASE air shower arrays
resolution Amanda-B10 ~ 3.5°
results in ~ 3° for upward moving muons
(Amanda-II: < 2°)
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AMANDA-II
AMANDA
Super-K
DUMAND Amanda-II:677 PMTsat 19 strings
(1996-2000)
80PMTs
302PMTs
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Preliminary limits (in units of 10-15 muons cm-2 s-1): Cas A: 0.6 Mk421: 1.4 Mk501: 0.8 Crab: 6.8 SS433: 10.5
Point Sources Amanda II (2000)
1328 events
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Expected sensitivity AMANDA 97-02 data
4 years Super-Kamiokande
8 years MACRO
170 days AMANDA-B10
-90 0-45 9045
10-15
10-14
cm-2 s
-1
declination (degrees)
southern sky
northern sky
SS-433
Mk-421 / ~ 1
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IceCube
1400 m
2400 m
AMANDA
South Pole
IceTop
- 80 Strings- 4800 PMT - Instrumented
volume: 1 km3
- Installation: 2004-2010
~ 80.000 atm. per year
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mediterraneum
Mediterranean Projects
4100m
2400m
3400mANTARESNEMO NESTOR
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Site: Pylos (Greece), 3800m depth towers of 12 titanium floors each supporting 12 PMTs
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-2400m
40 km
Submarine cable
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ANTARES Design
2500m2500m
300m300mactiveactive
Electro-opticElectro-opticsubmarine cablesubmarine cable ~40km~40km
Junction boxJunction box
Readout cablesReadout cables
Shore stationShore station
anchoranchor
floatfloat
Electronics containersElectronics containers
~60m~60mCompass,Compass,tilt metertilt meter
hydrophonehydrophone
Optical moduleOptical module
Acoustic beaconAcoustic beacon
~100m
10 strings12 m between storeys
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abs. length ~70 m80 km from coast 3400 m deep
NEMO Neutrino Mediterranean
Observatory
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NEMO 1999 - 2001 Site selection and R&D
2002 - 2004 Prototyping at Catania Test Site 2005 - ? Construction of km3 Detector
ANTARES 1996 - 2000 R&D, Site Evaluation 2000 Demonstrator line 2001 Start Construction
September 2002 Deploy prototype line December 2004 10 (12?) line detector complete 2005 - ? Construction of km3 Detector
NESTOR 1991 - 2000 R & D, Site Evaluation Summer 2002 Deployment 2 floors Winter 2003 Recovery & re-deployment with 4 floors Autumn 2003 Full Tower deployment 2004 Add 3 DUMAND strings around tower 2005 - ? Deployment of 7 NESTOR towers
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d
R
ACOUSTIC DETECTION•Suitable for UHE Threshold > 10 PeV•Particle shower ionization heat perpendicular pressure wave
P
t
50s
Attenuation of sea water → given a large initial signal, huge detection volumes
can be achieved.
Maximum of emission at ~ 20 kHz
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AUTEC array in Atlanticexisting sonar array for submarine detection
Atlantic Undersea Test and Evaluation Center
52 sensors on 2.5 km lattice (250 km2) 4.5 m above surface 1-50 kHz !
Threshold ~ 100 EeV
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RADIO DETECTION: Askaryan process
Interaction in ice:e + n p + e-
e- ... cascade
relativist. pancake ~ 1cm thick, ~10cm
each particle emits Cherenkov radiation
C signal is resultant of overlapping Cherenkov cones
Coherent Cherenkov signal for >> 10 cm (radio)
C-signal ~ E2
nsec
Compton scattered electrons shower develops negative net charge Qnet ~ 0.25 Ecascade (GeV).
Threshold > 10 PeV
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Showers in RF-transparent media (ice, rock salt)
RICE Radio Ice Cherenkov Experiment
firn layer (to 120 m depth)
UHE NEUTRINO DIRECTION
300 METER DEPTH
E 2 · dN/dE < 10-4 GeV · cm-2 · s-1 · sr-1
20 receivers + transmitters
at 100 PeV
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AntarcticImpulsiveTransientArray
Flight in 2006
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el.-magn.cascade
from e
hardmuons
from CR
EExtensive Air Showersxtensive Air Showersfor E > 10 EeV produce Ionization trails
Far inclined showers ( thousand per year)
Hard s
Atm
osphere
• Flat and thin shower front• Narrow signals• Time alignment
Deep inclined showers (~ one per year?)
Atm
osphere
Soft s + e.m.
• Curved and thick shower front• Broad signals
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Observation of upward going optical Cherenkov radiation emitted by tau neutrino -induced air-showers
Need an observation from above (satellite)
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Horizontal Air Showers seen by Satellite
500 km
60 °
E > 1019 eV
Area upto 106 km2
Mass upto 10Tera-tons
Horizontal air shower initiated deep in atmosphere
1 - 20 GZK ev./y
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OWL
Extreme Universe Space Observatory
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RICE AGASA
Amanda, Baikal2002
2004
2007
AUGER Anita
AABN
2012
km3
EUSOAugerSalsa
GLUE
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0.1 km3 and 1 km3 detectors underwater and ice
Conclusions
Contacts: Christian Spiering [email protected]
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P.G. PelferUniversity of Florence and INFN, Firenze, Italy
F. DubeckyInstitute of Electrical Engineering, Slovak Academy of
SciencesBratislava, Slovakia
A.OwensESA/ESTEC
Noordwijk,Netherland
P.G. PelferUniversity of Florence and INFN, Firenze, Italy
F. DubeckyInstitute of Electrical Engineering, Slovak Academy of
SciencesBratislava, Slovakia
A.OwensESA/ESTEC
Noordwijk,Netherland
Solar Neutrino Solar Neutrino Spectrometer Spectrometer with with InP InP DetectorsDetectors
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Why InP Solar Neutrino Experiment ?
Why InP Solar Neutrino Experiment ?
Semi Insulating InP Material
base material for:
Hard X-Ray Detectors
Fast Electronics and Optoelectronics
InP Spectrometer,
the Smallest, Real Time, Lower Energy
pp Solar Neutrino Spectrometer
The Solar Neutrino Spectrometer from/for R&D on InP X-Ray Detectors ?
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• BASIC KNOWLEDGE
• Solar Neutrino Physics• X-ray astronomy
• X-ray physics
• MEDICINE• Digital X-ray radiology (stomatology, mammography, ...)
• Positron emission tomography• Dosimetry
• NONDESTRUCTIVE ON-LINE PROCESS CONTROL• Material defectoscopy
• MONITORING• Environmental control
• Radioactive waste management• Metrology (testing of radioactive sources, spectrometry...)
• NATIONAL SECURITY• Contraband inspections: cargo control
• Detection of drugs and plastic explosives • Cultural heritage study
DETECTOR APPLICATIONS
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• Room temperature (RT) operation• Portability• Fast reaction rate• Universal detection ability• Good detection parameters: CCE, FWHM,
DE• Radiation hardness• Well established material technology • Well established device technology (10 m)
• FE Electronics and Optoelectronics integration on the Detector
• LOW COST
RT OPERATION: EG > 1.2 eV POLARISATION EFFECT: EG < 2.5 eV HIGH ENERGY RESOLUTION: EG small HIGH STOPPING POWER: Z > 30 HIGH CARRIER MOBILITY: > 2000 cm2/Vs
CANDIDATES
CdTe, HgI2, GaAs, InP
Requirements for Hard X-Ray Detectors of the New
Generation>10keV
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Attenuation and mobility
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Neutrino from the Sun
Neutrino from the Sun
ChlorineHomestakee + 37Cl 37Ar + e-
GalliumSAGE, Gallex, GNOe + 71Ga 71Ge + e-
WaterKamioka, SuperKx + e- x + e- (ES)
D2OSNOx + e- x + e- (ES)e + d p + p + e-
(CC)x + d n + p + e-
(NC)
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Requirements for Indium Solar Neutrino Spectrometer
Requirements for Indium Solar Neutrino Spectrometer
1. Indium incorporated into the detector
2. Energy resolution ∆E/E of the order of 25% at 600 keV. Important for spectrometry as well as background reduction.
3. Time resolution of the order of 100 ns for ~ 100 keV radiations.
4. Position resolution ∆V/V 10-7 at a reasonable cost. Very important for background reduction
5. Good energy resolution for low energy radiations ( ~ 50 keV )
6. Made with materials of high radiactive purity
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497.33 keV
E e(E - 118 keV ) + 115 Sn*
Delay = 4.76 sec
115Sn* 115Sn + e-(88 112 keV)/1 (115.6 keV) +
2(497.33 keV)
1/2= 4.76 sec
-
e
115In (95.7%)
1/2=6x1014 y
115Sn
612.81 keV9/2+
7/2+
1/2+
3/2+1
2
0
Neutrino Detection by In Target
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" prompt event “ in a “1 cm3
cell”
“ delayed event “ in a 27 cm3 macrocell
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3 4 5
6
789
12
3 4 5
6
789
e
1
2
10 s
time
Solar Neutrino Eventin InP Detector
Solar Neutrino Eventin InP Detector
Calorimeter Module
1 cm3 cell
106 InP “1 cm3 cell”
Detector made up of many ‘basic cells’
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100 mm 200 mm
Spectrometer Module
Spectrometer Building Block
Pad Detectors
V microcell 1 mm3
N microcell /cm3
1000
FULL NEUTRINO SPECTROMETERFULL NEUTRINO SPECTROMETER
Nmodules 125
1 neutrino event once a day for 1011 background events
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SemiInsulating InP Wafer6” 6” diameter, diameter, 1 mm1 mm thick
Pad Detectors
Basic Component ofNeutrino
Spectrometer
Present InP Material and Detector Technology
Present InP Material and Detector Technology
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SI InP Material and Detector Technology
SI InP Material and Detector Technology
Original BUFFERS realised using ion implantation in backside (PATENTED)
Symmetrical circular contact configuration, 2mm , using both-sided photolithography
Final metallisation: TiPtAu on top and AuGeNi on backside
Surface passivation by Silicon Nitride
Producer:
JAPAN ENERGY Co., Japan
Growth Technique:
LECHigh-Temperature Wafer Annealing
Resistivity (300 K): 4.9x107
cm
Hall Mobility (300K): 4410 cm2/Vs
Fe Content: 2x1015 cm-3
Orientation: <100>
Final Wafer Thickness: ~ 200 m
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3.142 mm2 x 200 m
InP Detector Test Setup
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E=2.4 keV at 5.9 keV : 8.5 keV at 59.54 keV
Energy Resolution vs Shaping Time andSpectral Response in InP Laboratory Measurements
Energy Resolution vs Shaping Time andSpectral Response in InP Laboratory Measurements
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2
12355.2/355.2
a
EaeEFE
Linearity and Resolution vs X Ray Energyin InP Laboratory Measurements
Linearity and Resolution vs X Ray Energyin InP Laboratory Measurements
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InP Spatial DistributionsInP Spatial Distributions
Count rate
Peak centroid
Resolvingpower
contact
bond wire
The detectors spatial response measured at HASYLAB using a 50 50 m2, 15 keV
X-ray beam.
54Contacts: Pier Giovanni.Pelfer [email protected]
Present Radiation Detectors based on Bulk SI InP Fe doped have very good Detection Parameters
for the X ray Detection
from HASYLAB SR FaciltyFWHM from 2.5 KeV at 5.9 KeV to 5.5 KeV at 100 KeV
DE 10% at 100 KeV for 200 m thick Detector
dueto Better Material from Japan Energyand to Improved Interface Technology
Some Problems for Detector Polarisation
Detectors performances good for Solar Neutrino Spectrometer
Optimisation is our next research goal
Summary and ConclusionsSummary and Conclusions
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A.Montanari, F.Odorici
INFN Bologna & Bologna University Italy
Application of Application of nanotechnologiesnanotechnologies in High Energy Physicsin High Energy Physics
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•Nanotechnologies characteristics•Technologies for processing material on a nanometric
scale: 1-100nm•Interests in many field of research: biology,
chemistry, nanoelectronic,science of material
Nano-objects very attractive also in terms of application to a
new generation of position particle detectorsNano-holes, nanochannelsNano-wires, nanotubes
Mask, dies
Contacts, probes
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•Single-Wall Carbon Nanotubes (SWNT) discovered in 1991
•Essentially long thin cylinders of carbon
Nanotubes introduction
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•Single-wall nanotubes are formed in a carbon arc in the presence of a metal catalyst. The tubes are found in the matted soot deposited on the reaction chamber wall low yield
•The As-Produced Soot contains tubes that are 0.7-1.2 nm in diameter and 2-20 µm in length. The product contains 10-40% tubes, the remainder is carbon-coated metal nanoparticles and amorphous and carbon nanoparticles
price list from Bucky USA [email protected]
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•NT can have very broad range of electrical, optical, mechanical, thermal characteristics depending on their geometrical properties (diameter, length and chirality)
•SWNT are truly 1D objects
•Beside SWNT it is possible to grow Multiple Walls Nano Tubes (MWNT)
Energy gap dependency
on diameter and chirality
Quantum conductance of
MWNT G0 = 2e2/h 1/12.9 k -1
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•Nanotransistor FET using NT as channel
Microphotograph from IBM website
•At low temperature, it becomes a Single Electron Transistor (SET)
NT applications
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FIELD EMISSION FROM ARRAYS OF CARBON NANOTUBES
The aligned Nanotube field emitter are grown on a silicon substrate, by CVD
Nanotubes array grown by CVD
20 left 2 right 1 separation min
from NanoLab website
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•Peculiar properties expected by the nanodimensions associated with NT filling:
•Superconductive phenomena (reported for K,Rb,Cs) at rel. high temp 50K
TEM image of KI@SWNT hybrid material
2 atoms crystal KI within 1.4nm SWNT
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•New concept: bundles of NT used for position detectors
Readout electronics
Radiation
•Filling of nanotubes already possible
Nanopixel detector
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•Require uniform and reproducible structure: using catalysts in chemical vapour deposition straight nanotubes are possible
Anodization of iperpure Aluminumsheets (100-300 mm thick ) undercontrolled conditions produces anoxide (Al2 O3 , Alumina) withself-organized regular honeycombstructure
The size and pitch of nanochannelsdepend on the parameters of theprocess (voltage, acid type,acid concentration, temperature): Pitch: 40 -> 400 nm
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Alumina nanochannels used to grow nanotubes
Alumina nanochannels can be used to grow CNs, after thedeposition of the catalyst (Ni, Fe, Co) at the bottom of each single pore
Growth of CN by Chemical Vapor Deposition of a hydrocarbur at 600- 800 o C
Temperature, gas concentration and duration of theprocess determine the CN structure (SWNT or MWNT, metallic or semiconductor)
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Alumina nanochannels growing
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NANO CHANNEL ACTIVE LAYER DETECTOR CONCEPT
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Conclusions
NanoChant project (INFN & CNR) started as an R&D study aimed at improving by one order of magnitude the spatial resolution of position particle detectors, by using nanotechnologies (Carbon Nanotubes grown inside Alumina Nanochannels)•Present state: building of the Alumina Nanochannels pore size 40nm pitch 100nm•Immediate next step: growing of CN inside Nanochannels •Future step: study of properties of CN, to optimise their use as charge collectors and their coupling to active medium
Contacts: [email protected]
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DIAMINE CollaborationWP-2 BARI, Italy
M. Abbrescia, G. Iaselli, T. Mongelli, A. Ranieri, R. Trentadue, V. Paticchio
Resistive Plate Chambers Resistive Plate Chambers as thermal neutron as thermal neutron
detectorsdetectors
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Reasons for new thermal neutron detectors
The humanitarian demining problem
Neutron Backscattering
Technique (NBT)
Metal Detectors not effective against anti- personnel mines:
•Neutron backscattering method: moderation of high-energy neutrons produced by radio-isotopic source or generator
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•Low (thermal) energy neutrons reflected from the soil is a direct indication of the amount of hydrogen •The amount of hydrogen in a plastic landmine is much higher (40-65%) than that of the surrounding soil even in case this is wet • A thermal neutron detector in combination with a neutron source is scanned across the soil, the presence of a landmine will be indicated by an increase in the number of thermal neutrons
GroundLandmine
252Cf source
Cosmics
and “fast” n RPC
Thermal n
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RPCs for thermal neutron detection
1) Bakelite electrodes2) Gap: 2 mm3) HV electrodes: graphite 100 m 4) High resistivity layer 5) Pick-up strips6)&7) readout electronicsOperating pressure: ~ 1 Atm
bakelite resistivity 10 10- 10 12 cm electrodes treated with linseed oil
RPCs are easy to build, mechanically robust, light-weighted, cheap, can cover large surfaces, are adapt for industrial production, etc.
particularly suitable for “on-field” applications
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Neutron Detection
Neutrons can be revealed only
after the interaction in a
suitable material
Production of secondary
ionising particles
The choice of the converter is crucial for the performance
of the detector
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Choice of the converterGd
• Natural Gd is characterized by a thermal neutron (50 kbarn) 12 times larger than 10B (3840 barn) • Produced electron range (15-30 m) is >than ’s (3-4 m)• Beyond E=100 meV, Gd cross section decreases much more rapidly than the one of 10B E1 eV it is smaller than the one of 10B.
For application concerning only thermal neutron detection Gd is preferable to 10B
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HV
•Layer of the converter consists of Gd2O3 mixed with linseed oil; the mixture is sprayed onto the bakelite electrodes, which are used to build standard RPC • It is possible to obtain extremely uniform layers, with very constant thickness and density
The electric properties (surface resistivity) of bakelite electrodes are not altered
Gas
•RPCs 10x10 cm2 in dimensions one without Gd2O3, used as a reference and two with a different concentration of the oil Gd2 O3 mixture •Signal readout: copper pad Signal input to: NIM discriminator, Vthr=30
•Operating voltage 10-11kV (streamer mode) gas mixture
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RPC with Gd-oil
TDC2
2 layers of 10B 0.35μm
U
e-
RPC
CI
TDC1
t0 start DAQ
tn stop to a multihit TDC
Schematic diagram of test system
TOA of e- plus delay start signal for two multihit TDC Neutron energy computed
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‘raw’ data show already the higher efficiency achieved using this method •Background noise (of the chamber, out of
time neutrons) to be taken into account
Relative efficiency of conversion:
CI
RPC
rel N
N around 2.5-3
times better
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Conclusions
•Demonstrated the feasibility of this approach to build Gd-RPC for thermal neutrons •Both detectors have an efficiency > 2.5 eff. CI ( 6%)
•RPC-Gd experimental efficiency is > 10B theoretical maximum efficiency >> 10B-RPC experimental efficiency
•Coupling two of these detectors together efficiency reaches about 3.5-4 eff. CI (analysis in progress)
Contacts: [email protected]
•Performances of various types of detectors have been evaluated by a technical board of EC together with Monte Carlo analysis of the signal generated by a APL.
•Decision on when and how to really test a device is being under consideration.
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Cinzia Da Via’
Brunel University, London, UK
ADVANCES IN SEMICONDUCTOR DETECTORS ADVANCES IN SEMICONDUCTOR DETECTORS FOR PARTICLE TRACKING IN EXTREME FOR PARTICLE TRACKING IN EXTREME
RADIATION ENVIRONMENTSRADIATION ENVIRONMENTS
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PHYSICS REQUIREMENTS AT LHC AND SHLC (1035 cm2s-1)
p p
Hb
b
SUCCESS OF THE EXPERIMENTSREQUIRE PRECISE MEASUREMENT OF
•MOMENTUM RESOLUTION•TRACK RECONSTRUCTION•B-TAGGING EFFICIENCY
POSSIBLE WITH SILICON, HOWEVER…
Higgs channel
INTRODUCTION
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RADIATION ENVIRONMENT AT LHC ANDEXPECTED AT SLHC
5*1015 5*1014
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SILICON DETECTORS NORMALLY USED IN HEP
PRESENT STATUS OF RAD HARD
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EFFECTS OF RADIATION DAMAGE IN SILICON DETECTORS
•Generation of charge traps by displacement damage of bulk silicon (interstitials and vacancies)
•Nuclear interactions
•Secondary processes from energetic displaced lattice atoms
Non Ionizing Energy Loss:Energy loss due to collision with lattice nuclei• depends on mass of the particle
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RADIATION INDUCED BULK DAMAGE
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RADIATION DEFECTS AND MACROSCOPIC EFFECTS
V,I mobile migrate until meet impurities and dopantsto form stable defects:
•Charge defects: Neff,Vbias
•Deep traps, recombination centers: signal charge loss
•Generation centers: Ileak noise
Oxygen-Vacancy complex forms an acceptor state in the upper half of band-gap (acts as a trapping center)
Neff
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MACROSCOPIC PARAMETERS CHANGES AT 1015 n/cm2
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SPACE CHARGE AFTER IRRADIATION
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COLLECTION DISTANCE DETERMINED BY DRIFT LENGTH
Leff= t*Vdrift
•Also effect of charge sharing due to low field region after type inversion
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MAIN DETECTORS STRATEGIES FOR SURVIVAL BEYOND 1015 n/cm2
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OXYGEN AND STANDARD SILICON
•Vfd reduced 3 times
•No improvements for neutrons
•Defect engineering:influence the defect kinetics by incorporation of impurities•Higher O content: less donor removal
VO
P
VO not harmful @ room T
VP donor removal
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SHORT DRIFT LENGTH USING 3D DETECTOR
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3D VERSUS PLANAR APPROACH
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E.Giulio Villani, Renato Turchetta, Mike Tyndel
Rutherford Appleton Laboratory
Analysis and Simulation of Charge Analysis and Simulation of Charge Collection in Collection in
Monolithic Active Pixel Sensors Monolithic Active Pixel Sensors (MAPS)(MAPS)
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Reset
Column line
Row sel
Column parallel ADCs
R C e oa n
d to ru ot l
Data processing – output stage
I2 C
•Charge generated by impinging radiation in sensitive element D diffuses towards the cathode.The related voltage variation is buffered by the source follower and transmitted further down the line once the row is selected. One row at a time is readout
MAPS CONCEPTS AND MAPS CONCEPTS AND CHARACTERISTICSCHARACTERISTICS
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P+ P+
P Sensitive volume(2 – 20 μm thick)
P++ Substrate(300 – 500 μm thick)
N+electronics
•Ionisation- generated charge remains confined within the potential well in the epitaxial layer and moves by thermal diffusion towards the cathode
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•Typical diffusion time for 5m active area is about 20ns, with 600e- collected (simulation performed with ISE-TCAD on device with 5m epitaxial thickness >10m substrate 2V bias)Sufficiently fast for Linear Collider: however, LHC would require faster and more Sufficiently fast for Linear Collider: however, LHC would require faster and more radiation tolerant deviceradiation tolerant device
F 20ns
Typical results
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New concept design and analysis: introduction of N-layer to extend electric field into active region
nRnGnnDtn 2
oSiz
2
2
KTFpEFiE
inKT
FiEFnEinANDNqz expexp)(
To be solved within the regions of the
device
N layer
Cathode
Active area
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DEVICE DESIGN
Simulation results: Electric field comparisonNEW STANDARD
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Superposition of voltage variations at the collecting cathode: new structure shows smaller swing than the standard structure but is faster regardless of the hit point
Fall time τF (0 to 90% of full swing) approximately 8.5 times smaller
τF 17ns
τF 2ns
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Charge collection time shows the same fast behavior with fall time τF 2ns
Total capacitance C 6.63fF
τF 2ns
NEW STANDARD
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CONCLUSIONS
• Results of 2D simulations on standard MAPS compare favorably with what amply reported in literature • New structure proposal: analysis suggests the possibility of performances improvements • Design and simulation: results show shorter collection time and better efficiency which pave the way for improved radiation tolerance Next steps:o Full 3D simulation of a device with side implantso Fabrication and testo Implementation of readout electronics
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PWy
PWx
DNWy
X
Y
Z
DSUB
New device structureNew device structure