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Laboratorio di Rivelatori di Radiazione

e Strumentazione Nucleare

Laboratorio di Rivelatori di Radiazionee Strumentazione Nucleare

Argomenti per tesi: (per studenti sia BIO che ELN)

• Rivelatori di immagini X e gamma per applicazioni nella

diagnostica medicale, nell’astronomia X su satellite e nello

studio delle materia

• Circuiti integrati per l’elaborazione di segnali da rivelatori

di radiazione per applicazioni scientifiche e industriali

Requisiti:

• conoscenze di base di elettronica

• attitudine/interesse all’attività sperimentale di laboratorio

• buona volontà

Dipartimento di Elettronica e Informazione - Sezione di Elettronica

Application of the SDD in g-ray spectroscopy and imaging

Advantages of SDDs with respect to other photodetectors:

• high quantum efficiency (~ 90 %) @ 565nm of CsI(Tl)• compact, mechanical robust• no statistical spread due to multiplication• low operating voltages • smaller sensitivity to bias and temperature variations • insensitivity to magnetic fields

g-ray

scintillator

SDD

Applications:

• medical imaging• gamma-ray astronomy• homeland security• nuclear physics experiments

Anger Camera based on SDDs

collimator

continuous scintillator CsI(Tl)

monolithic array of photodetectors

photodetector counts

Main advantages (vs. pixellated detectors, e.g. CdTe or CZT):

• spatial resolution (<mm) achieved with ~ 10 times larger photodetector pixel size

1/100 readout channels needed for a given spatial resolution

• good detection efficiency, adjustable vs. energy with scintillator thickness

Main disadvantage

Poorer energy resolution, especially at low energy, due to the scintillator conversion

(although new scintillators like LaBr3 are reducing this gap) and to the electronics noise

added by the several photodetectors used for the light readout

The HICAM gamma camera

The consortium:

• Politecnico di Milano, Italy

• MPI Halbleiterlabor, Germany

• L’ACN, Italy

• Nuclear Fields Holland

• UCL London, UK

• OORR-Bg, Italy

• Hospital San Pau, Barcelona, Spain

• University of Milan, Italy

• Cf Consulting, Italy

features:

• 10x10cm2 FOV

• intrinsic resolution ~ 1mm

• overall resolution ~ 2.5mm @5cm

• energy resolution ~ 10% @140keV

• compactness

• compatibility with MRI

Applications:

• planar clinical studies of spine and small

bones

• intra-operative imaging of breast cancer

and melanoma

• imaging of parathyroid and thyroid

• SPECT measures in test phantoms

• combined HI-CAM and MRI measures

• small animal imaging

(EC contract n. LSHC-CT-2006-037737)

10mm

10mm

1mm insensitive

bonding pads

bus lines

JFET

The SDD photodetector

• 1×5cm2 array

• ~ 20% dead area

• drift time <1us

• ARC transmittance

of 85% at 550nm (CsI(Tl))

scintillation entering side

drift

100cm225cm2

The detection module

The first camera prototype

• five 1×5cm2 modules

• T = -10°C

• flex cables to FE readout

• 1 readout ASIC (25ch)

for the whole camera

CsI(Tl) scintillator, 7mm thick

Roberta Peloso

Politecnico di Milano & INFN

Roberta Peloso

Politecnico di Milano & INFNNSS-MIC 2010, Knoxville, 2 Nov. 2010

~ 20% dead area

Assembly of 20 modules (100cm2 total) in the camera

120 mm

96 mm

Flat cables

to the FE electronics

detector modules

Peltier elements

heat dissipator

Roberta Peloso


Roberta Peloso


Biasing and readout electronics of the camera

25-channels readout circuit

0.35mm CMOS technology

flex from

detector module

25-channels

readout boards

(x4)

board including biasing

and interface with DAQ

(SPI programming and

data acquisition)

Roberta Peloso


Roberta Peloso


Data Acquisition System

ADCs

LVD

S in

terfa

ce

ASICs managementFrame event generation

Ethernet frame serviceEthernet control service

Ethernet clientSimple user interfaceProcessing software

PC

Roberta Peloso


Roberta Peloso


Gamma-ray qualification of the camera: flood irradiation

one unit was no moreoperative during tests

Source: 99Tc (140keV)

A uniform flood is used to derive theuniformity correction map

CsI:Tl10mm

Gamma-ray imaging: first results

99Tc source (140keV)

lead collimator

HICAM detector

Hole Ø=1mm

Pitch=3mm99Tc source placed at 90 cm

Roberta Peloso


Roberta Peloso


Irradiation with 99Tc through a grid (1)

Reconstruction ofthe gridby means ofcentroid algorithm

Roberta Peloso


Roberta Peloso


Roberta Peloso


Mean FWHM =1.91mm

Mean FWHM =2.01mm

10,8 cm

8,7 cm

Irradiation with 99Tc through a grid (2)

X

Y

Roberta Peloso


Roberta Peloso


Assembly of the camera head

Roberta Peloso


Roberta Peloso


Clinical trial: Thyroid acquisition

A)

B)

A)

B)

A)

B)

A)

B)

LEHRlenght =24 mmhole =1.11mmsepta thickness=0.16mm

A)

B)

A)

B)

A)

B)

A)

B)

hypo fixation at the left thyroid lobe

hyper fixation at the right thyroid lobe

HICAM

E-CAM

LEUHRlenght =45 mmhole =1.2mmsepta thickness 0.2mm

Roberta Peloso


Roberta Peloso


Clinical trial: Lymphoscintigraphy

50 m

m50 m

m

Lymphoscintigraphy to localize the sentinel node

HICAME-CAM

Roberta Peloso


Direct labelling

In vivo migration to LymphoNodes

of labelled and loaded DendriticCells

4

Imaging (MRI , Scint.)

mDC injection

Antigen Loading

2Labelling

with MNPs

mDC

3

111In-oxine

labelling Harvesting and

differentiation

1

iDC

Dendritic Cellpart of the immune system

Preclinical trials: cells imaging (1)

Roberta Peloso


Day 0 - 4 h

Tests carried out at Ospedale Sacco, Milano

DC+Ag+TNFa111In

Injection site

2 lymph nodes

Day 1 Day 2

kidneylymph node

Preclinical trials: cells imaging (2)

Shielded Injection site

Roberta Peloso


Roberta Peloso


0 10000000 20000000 30000000

Brain

Thymus

Lungs

Heart

Liver

Spleen

Kidneys

Muscle

cpm/gr

In vivo imaging of Human Skeletal Muscle Cells (HSKMC)

Preclinical trials: cells imaging

HICAM

BIL

Perspective of gamma-ray imaging at medium-high energies (~MeV)

note: Compton interaction dominant

more than one interaction produces light in the scintillator

reconstruction has to retrieve multiple interactions from the

integral light distribution collected in the camera

possible solution: use Neural Networks reconstruction algorithm

05

1015

2025

3035

4045

50 0

5

10

15

20

25

30

35

40

45

50

0

500

1000

1500

2000

2500

Y

X

Photo

ns C

ount

first

interactionsecond

interaction

FWHM – Gaussian

FittingX Axis [mm] Y Axis [mm] Z Axis [mm] Energy [keV]

First Interaction Point 1.6 1.4 1.8 8.9

Second Interaction Point 2.6 2.9 3.5 -

FWHM – Gaussian

FittingX Axis [mm] Y Axis [mm] Z Axis [mm] Energy [keV]

First Interaction Point 1.6 1.4 1.8 8.9

Second Interaction Point 2.6 2.9 3.5 -

E=1MeV



70/30 USR BrukerBiospin

Static magnetic field: 7 Tesla

Magnetic field gradient: 240 mT/m

RF signal: 300 MHz

Detection module in the imaging region

Detection module Phantom

No distortions

in the MRI image

• No relevant effects on SDD

signals in the 7T field

• spectrum with RF ON not

different from RF OFF

Compatibility of the SDD (1cm2 unit) with MRI

LED spectrum

2.5% FWHM

Istituto Mario Negri, Milan

Dresden, Germany, NSS 2008 [email protected]


ASIC for SDDs



9th-order shaping amplifier



poles position



Semigaussian Parallel poles

simulations measurements

Tshaping ~ 140ns

Tpeaking ~ 470ns

Twidth 1% ~ 796ns

Tshaping ~ 176ns

Tpeaking ~ 600ns

Twidth 1% ~ 1016ns

Tshaping ~ 156ns

Tpeaking ~ 530ns

Twidth 1% ~ 760ns

Tshaping ~ 206ns

Tpeaking ~ 700ns

Twidth 1% ~ 1004ns



The readout electronics and the DAQ system

40 channels

readout board

ASIC

front-end electronicsboards

USBconnectionto PC

ADCsboards



WFI (Wide Field Imager)

Detector type: Active Pixel DEPFET

Number of pixels: 1024 × 1024

Dynamic Range: 100 eV – 30 keV

Energy resolution: 125 eV @ 6 keV

Noise: 3-5 e- ENC

Time resolution: 200 Hz in Full Frame Mode

Processing Time: 4 μs

The IXO MISSION

IXO International X-ray Observatory

Exploring the early universe by imaging in the X-ray

band.

Telescope Strategy

VELA

http://it.wikipedia.org/wiki/Immagine:Logo-nasa-800px.png



DePFET matrices



The VELA Current Readout Scheme

Gq = 200 pA/el

Trapezoidal

Shaper

Virtual Ground

Current Source

Current Step

No change in DEPFET voltages during the readout.

The gain in not limited by the DEPFET output resistance

Fast readout

High bias current to

achieve best resolution



VELA ASIC layout

0.35 µm AMS CMOS, 3.3V

Chip size is 5.2 mm x 4.6 mm

Milano, 22 Luglio 2008 X-Ray Free Electron Laser 33

“XFEL”= X-Free Electron Laser (@Hamburg-Bahrenfeld)

proprietà ottiche dei laser convenzionali

+differenti principi di funzionamento:

Il progetto XFEL

Macro-bunching&SASE(Self-Amplified-Spontaneous-Emission)‏


Politecnico di Milano & INFNMilano, 22 Ottobre 2009 34

Il progetto Europeo di XFEL

• In costruzionenell’area di Amburgo

• Struttura temporaleflessibile degli impulsi(fmax = 5MHz)

IBM 130nm, VDD =1.2V, risoluzione ADC = 8bitServe un canale di lettura per ogni pixel (ca. 200μm x 200μm)

Amplificazione, filtraggio, conversione, memorizzazione

Piano focale:1024 x 1024 pixels

Leicester, 1 October 2010 [email protected]


Flip Capacitor Filter (FCF)

Trapezoidal weighting-functions are with one Amplifier

Using MIM CAP of 6.4 pF the area is 200 um x 16 um (16% pixel area)

Power below 1.5 mW/ch (6 Watt for the total ASIC)

Trapezoidal FilterCF = 1.5 pF

Gain adjustment

by changing CF

Offset

adjustment


Politecnico di Milano & INFNMilano, 22 Ottobre 2009 36

Layout della struttura

Nell’ASIC:

•Flip CapacitorFilter• Generatoreprogrammabile• Logica di controllo switch• Stadio S&H• Buffer di uscita• Impiego di unsequencer• Ingressi di test

Leicester, 1 October 2010 [email protected]


Use of VELA-like circuits for CCDs readout

Voltage readout

• conventional source follower

• V/I conversion + integration

• VELA ‘optimum’ filter

• speed of SF most probably not an

issue at short processing times

• VELA-like circuits may be suitable also for CCD readout

• goal: readout of (column-parallel) CCDs at high speed (warmer CCD Temp.?)

• two readout options to be evaluated:

filterCCD

SF

preamplifier

V/I

conv.

filterCCD

programmable

current source

I

Current readout

• FET current directly integrated in

the filter

• simpler architecture

• VELA ‘optimum’ filter

• new solution (study started now)

Progettazione di circuiti integrati: schematico e simulazioni

Progettazione di circuiti integrati: layout

Progettazione di circuiti integrati: post-layout

Sviluppo del set-up sperimentale e test



Lista tesi disponibili

• La gamma camera HICAM: ottimizzazione e applicazioni

• Imager per gamma ad alta energia (reti neurali)

• Circuito VELA per la lettura di CCD

• Circuito integrato per SDD per IXO e per un esperimento

di fisica nucleare (Siddharta) ai laboratori INFN di Frascati

• Circuito per la lettura di pixels nel progetto XFEL

• Diversi circuiti per spettroscopia X e per sistemi di

monitoraggio delle radiazioni (imp. nucleare, sicurezza,

identificazione di sorgenti radioattive nei rottami metallici

utilizzati nelle acciaierie, ecc.)*

*tesi nell’ambito‏di‏collaborazioni‏con‏industrie

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