Danilo Domenici G.Bencivenni, M.Calvetti, C.D’Ambrosio, M.Poli Lener The HPPC: a proposal for a...
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Transcript of Danilo Domenici G.Bencivenni, M.Calvetti, C.D’Ambrosio, M.Poli Lener The HPPC: a proposal for a...
Danilo Domenici
G.Bencivenni, M.Calvetti, C.D’Ambrosio, M.Poli Lener
The HPPC: a proposal for a new The HPPC: a proposal for a new gaseous detector for Positron gaseous detector for Positron
Emission Tomography with Emission Tomography with high space and time resolution high space and time resolution
2 Danilo DomeniciFrascati, 22 giugno 2006
Componenti Gruppo HPPC
Giovanni Bencivenni 30%
Mario Calvetti 50%
Chiara D’Ambrosio 100%
Danilo Domenici (Resp. Naz.) 80%
Marco Poli Lener 20%
TOT FTE 2.8
Contatti con TERA per l’organizzazione di un workshop su PET-Online
3 Danilo DomeniciFrascati, 22 giugno 2006
Positron Emission Tomography
4 Danilo DomeniciFrascati, 22 giugno 2006
Small Animal PET Motivations
Humans and mice have 95% of common genes
mice are a platform for simulating human diseases
1 mm FWHM ( 1 mm3)
6 mm FWHM (200 mm3)
Dedicated R&D and detectors needed to fulfill the high-resolution requirements
Validation of new detectors concept is needed to access clinical cases
Body weight
Brain(cortex apex-
temporal lobe)Heart
Aorthic cannula
()
Man ~70 kg ~105 mm ~300 g ~30 mm
Mouse
~20 g ~6 mm ~0.1 g ~1 mm
5 Danilo DomeniciFrascati, 22 giugno 2006
How to improve PET?Space
resolutionSensitivity
Energy resolution
Human ~ 6 mm High
needed to reject
scattered events
Small Animal
1 mmif low the
dose can be raised
not needed (negligible diffusion)
Multilayer design N x (conversion layer
+ active detector)
DOI measurement
parallax correction
Active detector micro-gap Resistive Plate
Chamber
Very high time resolution
random rejection
Multilayer
gas detector
6 Danilo DomeniciFrascati, 22 giugno 2006
Random coincidencesOff-center emission
Parallax error
Random events 2tw Time resolution
Depth Of Interaction determinationTOF + DOI constraint on
Z reconstruction
DOI + TOF Advantages
DOI: coordinate of photon interaction along the line of flight
needed to correct parallax error for events far from tomography axis
DOI + TOF: rough estimation of the coordinate of positron annihilation
Possible solution: HPPC
7 Danilo DomeniciFrascati, 22 giugno 2006
HPPC Principle Of Operation
glass electrode (resistive material)
Parallel plate detector with resistive electrode
Thin gap (~500 μm) to enhance the time resolution (~200 ps)
Robust, reliable and relatively inexpensive
Can be used for photon detection with suitable converter
Modularity naturally allows a multi-layer design to increase efficiency
No energy measurement
~300m
gold electrode (photon
converter)
Avalanche operation with
C2H2F4 – iC4H10 – SF6
8 Danilo DomeniciFrascati, 22 giugno 2006
HPPC Single Layer Design
Hybrid: the anode is resistive (glass), the cathode is conductive (gold)
50μm kapton with 3μm gold film
500μm FR4 spacers outside active area
gas gap
550μm float glass
50μm kapton with 5μm X-strips
50μm kapton with 5μm Y-strips
HV distribution resistive coating
(~1MΩ/)
+ HV
GND
Many single layers are stacked to realize one detector
kapton circuit supports the cathode of the
following layer
FOV: 100x100 mm2
9 Danilo DomeniciFrascati, 22 giugno 2006
HPPC Tower Design
48 stacked single RPC
Readout planes are 4-fold ORed
X-Y: 4 mm digital readout pitch
(OR of 10 strips: 1.2 mm spatial resolution)
Z: ~2 mm measurement of Depth Of
Interaction (OR of 4 layers: 12 planes for
parallax correction)
~200 ps time resolution
~10% photon efficiency
~100x100 mm2 Field Of View
2 heads for coincidences detection
Basic design of HPPC for high-resolution PET scanner
10 Danilo DomeniciFrascati, 22 giugno 2006
HPPC Prototype Parts
Glass electrode with resistive coating to
distribute HV
Gold electrode deposited on kapton foil with FR4
frame
11 Danilo DomeniciFrascati, 22 giugno 2006
HPPC FLUKA Simulation Results
HPPC space resolution
1.2mm
physical PET resolution limit 0.5mm FWHM
efficiency vs gold thickness
PET and HPPC intrinsic space
resolutions
gold thickness limited by economical reasons
12 Danilo DomeniciFrascati, 22 giugno 2006
HPPC Photon Position Sensitivity
hit spatial positionX-Y view
peak separation
2 gaussian (σ = 0.2 mm) sources separated by 1mm
FWHM = 0.52 mm~5% fraction of scattered events
10% degradation on resolution due to electron range
13 Danilo DomeniciFrascati, 22 giugno 2006
Stato attivita`
Attivita` 2006 finanziata dalla DIREZIONE LNF (~100 k€)
Acquisto circuiti readout per 4 layers
Acquisto parti meccaniche
Avvio laboratorio dedicato (Sistemi GAS, DAQ, HV)
Previsione attivita’ 2006
Test di funzionalita`con prototipo a bassa efficienza (4 layers)
Previsione attivita`2007+2008
Costruzione prototipo piena efficienza (48 + 48 double head)
Realizzazione ~500 canali di elettronica a componenti discreti
Test completo con sorgente di positroni e fantoccio ad acqua
14 Danilo DomeniciFrascati, 22 giugno 2006
Richieste 2007
CONSUMI
Circuiti readout+converter (CERN) 20 k€
Elettronica di Front-End 10 k€
Verniciatura resistiva vetri 5 k€
Cavi, connettori, gas, metabolismo 5 k€
TOTALE 45 k€
MISSIONI ESTERE
Contatti ditte e enti (CERN, TERA) 5 k€
TOTALE 45 k€