1. Giulio Villani 20/11/2002
8th Topical Seminar on Innovative Particle and Radiation Detectors Siena, 21 – 24 October 2002
Giulio Villani 20/11/2002

2. SIENA 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

3. 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 Quercia
The horse race (Palio) is held here, 2nd of July and 16th of August
Of medieval origin, sees the 10 of the 17 contrade competing against each other: the winner gets the Palio (banner)

4. The Dome,XIV century: one of the best roman-gothic architectural examples
Masterpieces by Nicola Pisano, Donatello,Pinturicchio
Floor consisting of 56 different mosaics, depicting sacred scenes, required more than 150 years to be completed

5. High Energy Neutrino Astronomy
Giulio Villani 20/11/2002
High Energy Neutrino Astronomy
Christian Spiering,
Siena, October 2002
Giulio Villani 20/11/2002

6. Physics Goals A. High Energy Neutrino Astrophysics B. Particle Physics
Giulio Villani 20/11/2002
Physics Goals
A. High Energy Neutrino Astrophysics
Weakly interacting neutrinos reach us from very distant sources:
possible invaluable instrument for high-energy astrophysics
B. Particle Physics
Magnetic Monopoles, Oscillations,
Neutrino Mass ...
C. Others
Supernova Bursts, CR composition,
Black Holes, ...
Giulio Villani 20/11/2002

7. Cosmic Rays
1 TeV
GZK cut-off

8. up to 1-10 PeV Crab nebula Supernova shocks expanding in
interstellar medium
up to 1-10 PeV
Crab nebula

9. Active Galaxies: accretion disk and jets
up to eV
VLA image of Cygnus A

10. Underwater Air showers Underground Radio,Acoustic pp core AGN
p blazar jet
log(E2  Flux)
Top-down
WIMPs
Oscillations
GZK
GRB
(W&B)
Microquasars etc.
log(E/GeV)
TeV PeV EeV

11. Diffuse Fluxes: Predictions and Bounds
Mannheim & Learned,
2000
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
Macro
Baikal
Amanda 9

12. Detection Methods and Projects
Giulio Villani 20/11/2002
Detection Methods and Projects
Underwater/Ice Cerenkov Telescopes
Acoustic Detection
Radio Detection
Detection by Air Showers
Giulio Villani 20/11/2002

13. Underwater/Ice Cerenkov Telescopes
Giulio Villani 20/11/2002
Strings of widely spaced PMT put in deep water
4-string stage (1996)
AMANDA: Antarctic Muon And Neutrino Detector Array
Giulio Villani 20/11/2002

14. Cerenkov radiation in H2O : v0.75c,  = tg-1[(n2 v2/c2-1)1/2]
High-energy neutrinos through the earth may interact and create muons which emit Cherenkov light
muon
cascade

15.  resolution Amanda-B10 ~ 3.5°
1 km
2 km
SPASE air shower arrays
 resolution Amanda-B10 ~ 3.5°
results in ~ 3° for upward moving muons
(Amanda-II: < 2°)

16. AMANDA Amanda-II: 677 PMTs at 19 strings (1996-2000) 80PMTs Super-K
DUMAND
Amanda-II:
677 PMTs
at 19 strings
( )
AMANDA-II

17. Point Sources Amanda II (2000)
1328 events
Preliminary limits (in units of muons cm-2 s-1):
Cas A: Mk421: Mk501: Crab: SS433: 10.5

18. Expected sensitivity AMANDA 97-02 data
m  cm-2 s-1
southern
sky
northern
sky
4 years Super-Kamiokande
10-14
170 days
AMANDA-B10
8 years
MACRO
SS-433
10-15
Expected sensitivity AMANDA data
Mk-421 / ~ 1
-90
-45 90 45
declination (degrees)

19. IceCube - 80 Strings - 4800 PMT Instrumented volume: 1 km3
AMANDA
South Pole
IceTop
IceCube
- 80 Strings
PMT
Instrumented volume: 1 km3
Installation:
~ atm. per year

20. mediterraneum Mediterranean Projects 2400m ANTARES 4100m 3400m NEMO
NESTOR

21. Site: Pylos (Greece), 3800m depth
towers of 12 titanium floors each supporting 12 PMTs

22. 40 km
Submarine cable m

23. ANTARES Design 10 strings 12 m between storeys Shore station float
active
Electro-optic
submarine cable
~40km
Junction box
Readout cables
Shore station
anchor
float
Electronics containers
~60m
Compass,
tilt meter
hydrophone
Optical module
Acoustic beacon
~100m
10 strings
12 m between storeys

24. NEMO Neutrino Mediterranean Observatory
abs. length ~70 m
80 km from coast 3400 m deep

25. Summer 2002 Deployment 2 floors
NESTOR
R & D, Site Evaluation
Summer Deployment 2 floors
Winter Recovery & re-deployment with 4 floors
Autumn Full Tower deployment
Add 3 DUMAND strings around tower
? Deployment of 7 NESTOR towers
ANTARES
R&D, Site Evaluation
Demonstrator line
Start Construction
September Deploy prototype line
December (12?) line detector complete
? Construction of km3 Detector
NEMO
Site selection and R&D
Prototyping at Catania Test Site
? Construction of km3 Detector

26. R Suitable for UHE Threshold > 10 PeV d ACOUSTIC DETECTION 50s
Particle shower  ionization  heat  perpendicular pressure wave
Maximum of emission at ~ 20 kHz d R P t
50s
Attenuation of sea water
→ given a large initial signal,
huge detection volumes
can be achieved.

27. AUTEC array in Atlantic existing 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

28. 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

29. South Pole E 2 · dN/dE < 10-4 GeV · cm-2 · s-1 · sr-1
Showers in RF-transparent media (ice, rock salt) RICE Radio Ice Cherenkov Experiment
South Pole
firn layer (to 120 m depth)
20 receivers + transmitters
UHE NEUTRINO
   
DIRECTION
E 2 · dN/dE
< 10-4 GeV · cm-2 · s-1 · sr-1
at 100 PeV
300 METER DEPTH

30. AntarcticImpulsiveTransientArray
Flight in 2006

31. Extensive Air Showers for E > 10 EeV produce Ionization trails
Far inclined showers ( thousand per year)
Hard  s
Atmosphere
Flat and thin shower front
Narrow signals
Time alignment
Deep inclined showers (~ one per year?)
Atmosphere
Soft  s + e.m.
Curved and thick shower front
Broad signals
el.-magn.
cascade
from e
hard
muons
from CR
Extensive Air Showers
for E > 10 EeV produce
Ionization trails

32. Need an observation from above (satellite)
Observation of upward going optical Cherenkov radiation emitted by tau neutrino -induced air-showers
Need an observation from above (satellite)

33. Horizontal Air Showers seen by Satellite
500 km
60 °
E > 1019 eV
Area up
to 106 km2
Mass up
to 10
Tera-tons
Horizontal
air shower
initiated deep
in atmosphere
GZK ev./y

34. OWL Orbiting Wide-angle Light-collectors
Extreme Universe Space Observatory
OWL
Orbiting Wide-angle Light-collectors

35. RICE
AGASA
Amanda, Baikal
2002
2004
GLUE
AUGER nt
Anita
AABN
2007
2012
km3
EUSO
Auger
Salsa

36. Most promising: point sources
Conclusions
Most promising: point sources
0.1 km3 and 1 km3 detectors underwater and ice
Huge step in GZK region
Exciting decade ahead
Contacts: Christian Spiering

37. Solar Neutrino Spectrometer with InP Detectors
P.G. Pelfer
University of Florence and INFN, Firenze, Italy
F. Dubecky
Institute of Electrical Engineering, Slovak Academy of Sciences
Bratislava, Slovakia
A.Owens
ESA/ESTEC
Noordwijk,Netherland

38. Why InP Solar Neutrino Experiment ?
Giulio Villani 20/11/2002
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 ?
Giulio Villani 20/11/2002

39. DETECTOR APPLICATIONS
Giulio Villani 20/11/2002
DETECTOR APPLICATIONS
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
Giulio Villani 20/11/2002

40. Requirements for Hard X-Ray Detectors of the New Generation >10keV
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

41. Attenuation and mobility
Giulio Villani 20/11/2002
Attenuation and mobility
Giulio Villani 20/11/2002

42. Neutrino from the Sun Water Kamioka, SuperK x + e-  x + e- (ES)
Gallium
SAGE, Gallex, GNO
e + 71Ga  71Ge + e-
Chlorine
Homestake
e + 37Cl  37Ar + e-
D2O
SNO
x + e-  x + e- (ES)
e + d  p + p + e- (CC)
x + d  n + p + e- (NC)

43. Giulio Villani 20/11/2002
Giulio Villani 20/11/2002

44. Requirements for Indium Solar Neutrino Spectrometer
Giulio Villani 20/11/2002
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
Giulio Villani 20/11/2002

45. Neutrino Detection by In Target
Giulio Villani 20/11/2002
Neutrino Detection by In Target
1/2= 4.76  sec
7/2+
keV e
9/2+ 1
3/2+
keV
115In (95.7%) - 2
1/2=6x1014 y
1/2+
115Sn
E    e(E keV ) Sn* 
 Delay  = 4.76  sec 
 115Sn*  115Sn + e-(88  112 keV)/1 (115.6 keV) +  2( keV)
Giulio Villani 20/11/2002

46. Solar Neutrino Event in InP Detector
Giulio Villani 20/11/2002
“ delayed event “ in a 27 cm3 macrocell
Solar Neutrino Event
in InP Detector
" prompt event “ in a “1 cm3 cell” 3 4 5 2 2 1 6 1 3 4 5 9 8 7
time 2 1 6 e 9 8 7
10 s
1 cm3 cell
Detector made up of many ‘basic cells’
106 InP “1 cm3 cell”
Calorimeter Module
Giulio Villani 20/11/2002

47. FULL NEUTRINO SPECTROMETER Spectrometer Building Block
Nmodules  125
Spectrometer Module
100 mm
200 mm
Pad Detectors
V microcell  1 mm3
N microcell /cm3  1000
1 neutrino event once a day for background events

48. SemiInsulating InP Wafer Neutrino Spectrometer
6” diameter, 1 mm thick
Pad Detectors
Basic Component of
Neutrino Spectrometer
Present InP Material and Detector Technology

49. SI InP Material and Detector Technology
Producer:
JAPAN ENERGY Co., Japan
Growth Technique:
LEC
High-Temperature Wafer Annealing
Resistivity (300 K): x107 cm
Hall Mobility (300K): cm2/Vs
Fe Content: x1015 cm-3
Orientation: <100>
Final Wafer Thickness: ~ 200 m
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

50. InP Detector Test Setup
3.142 mm2 x 200 m

51. Energy Resolution vs Shaping Time and
Spectral Response in InP Laboratory Measurements
E=2.4 keV at 5.9 keV : 8.5 keV at keV

52. Linearity and Resolution vs X Ray Energy
in InP Laboratory Measurements

53. InP Spatial Distributions
The detectors spatial response measured at HASYLAB using a 50  50 m2, 15 keV X-ray beam.
InP Spatial Distributions
contact
bond wire
Count rate
Peak centroid
Resolving
power

54. Summary and Conclusions
Giulio Villani 20/11/2002
Summary and Conclusions
Present Radiation Detectors based on Bulk SI InP Fe doped
have very good Detection Parameters
for the X ray Detection
from HASYLAB SR Facilty
FWHM 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
due
to Better Material from Japan Energy
and to Improved Interface Technology
Some Problems for Detector Polarisation
Detectors performances good for Solar Neutrino Spectrometer
Optimisation is our next research goal
Contacts: Pier Giovanni.Pelfer
Giulio Villani 20/11/2002

55. Application of nanotechnologies in High Energy Physics
Giulio Villani 20/11/2002
Application of nanotechnologies in High Energy Physics
A.Montanari, F.Odorici
INFN Bologna & Bologna University Italy
Giulio Villani 20/11/2002

56. 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 detectors
Mask, dies
Contacts, probes
Nano-holes, nanochannels
Nano-wires, nanotubes

57. Nanotubes introduction
Single-Wall Carbon Nanotubes (SWNT) discovered in 1991
Essentially long thin cylinders of carbon

58. price list from Bucky USA website buckyusa@flash.net
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 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 website

59. SWNT are truly 1D objects
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

60. Nanotransistor FET using NT as channel
NT applications
Nanotransistor FET using NT as channel
Microphotograph from IBM website
At low temperature, it becomes a Single Electron Transistor (SET)

61. 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

62. 2 atoms crystal KI within 1.4nm SWNT
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 hybrid material
2 atoms crystal KI within 1.4nm SWNT

63. New concept: bundles of NT used for position detectors
Readout electronics
Radiation
Filling of nanotubes already possible
Nanopixel detector

64. Require uniform and reproducible structure: using catalysts in chemical vapour deposition straight nanotubes are possible
Anodization of iperpure Aluminum
sheets ( mm thick ) under
controlled conditions produces an
oxide (Al2 O3 , Alumina) with
self-organized regular honeycomb
structure
The size and pitch of nanochannels
depend on the parameters of the
process (voltage, acid type,
acid concentration, temperature):
Pitch: 40 -> 400 nm

65. · Alumina nanochannels used to grow nanotubes
Alumina nanochannels can be used to grow CNs, after the
deposition of the catalyst (Ni, Fe, Co) at the bottom of each single pore
Growth of CN by Chemical Vapor Deposition of a hydrocarbur at o C
Temperature, gas concentration and duration of the
process determine the CN structure (SWNT or MWNT, metallic or semiconductor)

66. Alumina nanochannels growing

67. NANO CHANNEL ACTIVE LAYER DETECTOR CONCEPT

68. Contacts: Alessandro.Montanari@bo.infn.it
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:

69. Resistive Plate Chambers as thermal neutron detectors
DIAMINE Collaboration
WP-2 BARI, Italy
M. Abbrescia, G. Iaselli, T. Mongelli,
A. Ranieri, R. Trentadue, V. Paticchio

70. 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

71. 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

72. RPCs for thermal neutron detection
1) Bakelite electrodes
2) Gap: 2 mm
3) HV electrodes: graphite 100 m
4) High resistivity layer
5) Pick-up strips
6)&7) readout electronics
Operating pressure: ~ 1 Atm
bakelite resistivity 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

73. 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

74. 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 E1 eV it is smaller than the one of 10B.
For application concerning only thermal neutron detection Gd is preferable to 10B

75. 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 HV
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 
The electric properties (surface resistivity) of bakelite electrodes are not altered

76. Schematic diagram of test system
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
TOA of e- plus delay start signal for two multihit TDC Neutron energy computed

77. ·     ‘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:
around times better

78. Conclusions Contacts: marcello.abbrescia@ba.infn.it
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 eff. CI (analysis in progress)
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.
Contacts:

79. Brunel University, London, UK
Giulio Villani 20/11/2002
ADVANCES IN SEMICONDUCTOR DETECTORS FOR PARTICLE TRACKING IN EXTREME RADIATION ENVIRONMENTS
Cinzia Da Via’
Brunel University, London, UK
Giulio Villani 20/11/2002

80. SUCCESS OF THE EXPERIMENTS REQUIRE PRECISE MEASUREMENT OF
INTRODUCTION
PHYSICS REQUIREMENTS AT LHC AND SHLC (1035 cm2s-1) p p H b
Higgs channel
SUCCESS OF THE EXPERIMENTS
REQUIRE PRECISE MEASUREMENT OF
MOMENTUM RESOLUTION
TRACK RECONSTRUCTION
B-TAGGING EFFICIENCY
POSSIBLE WITH SILICON, HOWEVER…

81. RADIATION ENVIRONMENT AT LHC AND
EXPECTED AT SLHC
5*1015
 5*1014

82. PRESENT STATUS OF RAD HARD
SILICON DETECTORS NORMALLY USED IN HEP

83. 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

84. RADIATION INDUCED BULK DAMAGE

85. RADIATION DEFECTS AND MACROSCOPIC EFFECTS
V,I mobile migrate until meet
impurities and dopants
to 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

86. MACROSCOPIC PARAMETERS CHANGES AT 1015 n/cm2

87. SPACE CHARGE AFTER IRRADIATION

88. Leff= t*Vdrift COLLECTION DISTANCE DETERMINED BY DRIFT LENGTH
Also effect of charge sharing due to low field region after type inversion

89. MAIN DETECTORS STRATEGIES FOR SURVIVAL BEYOND 1015 n/cm2

90. OXYGEN AND STANDARD SILICON
Defect engineering:influence the defect kinetics by incorporation of impurities
Higher O content: less donor removal O
VO not room T V
Vfd reduced 3 times
No improvements for neutrons P
VP donor removal

91. SHORT DRIFT LENGTH USING 3D DETECTOR

92. 3D VERSUS PLANAR APPROACH

93. Contacts: Cinzia.DaVia@brunel.ac.uk
CONCLUSIONS:
Contacts:

94. Analysis and Simulation of Charge Collection in Monolithic Active Pixel Sensors (MAPS)
E.Giulio Villani, Renato Turchetta, Mike Tyndel
Rutherford Appleton Laboratory

95. MAPS CONCEPTS AND CHARACTERISTICS
R C
e o
a n
d t
o r
u o
t l
Reset
Column line
Row sel
Column parallel ADCs
I2 C
Data processing – output stage
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

96. 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

97. Typical results
F  20ns
Typical diffusion time for 5m active area is about 20ns, with 600e- collected (simulation performed with ISE-TCAD on device with 5m epitaxial thickness >10m substrate 2V bias)
Sufficiently fast for Linear Collider: however, LHC would require faster and more radiation tolerant device

98. To be solved within the regions of the device
New concept design and analysis: introduction of N-layer to extend electric field into active region
N layer
Cathode
Active area
To be solved within the regions of the device

99. Simulation results: Electric field comparison
DEVICE DESIGN
Simulation results: Electric field comparison
NEW
STANDARD

100. 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
τF 2ns
τF 17ns
Fall time τF (0 to 90% of full swing) approximately 8.5 times smaller

101. NEW
STANDARD
τF  2ns
Charge collection time shows the same fast behavior with fall time τF  2ns
Total capacitance C  6.63fF

102. 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 implants
o     Fabrication and test
o     Implementation of readout electronics

103. New device structure
PWy
PWx
DNWy X Y Z
DSUB