camera ccd in sviluppo allxuvlab per un esperimento su razzo, precursore dellesperimento uvc del...
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Camera CCD in sviluppo all’XUVLab per un esperimento su razzo, precursore dell’esperimento UVC del Solar Orbiter
Compact (72mm x 72mm x 50mm)
Lightweight Fully vacuum compatible 4096 x 4096 maximum
CCD format Three-stage Peltier cooler Two available thermal
links between the CCD and the TEC (ΔT=-85°C/-60°C)
Very low noise preamplifier stage (1.8 nV/Hz r.m.s.)
Forme d’onda del CCD (fasi orizzontali in alto e verticali in basso) come appaiono ad uno strumento chiamato “analizzatore di stati logici”
Problemi dei rivelatori UV
low UV sensitivity, unstable,
not radiation hard, highly visible sensitive
PhotomultipliersPhotomultipliers
CCDCCD
Photodiodes
(a-Si, treated Si, Al)
Photodiodes
(a-Si, treated Si, Al)
Micro-Channel PlatesMicro-Channel Plates high voltage, hygroscopic photocathodes, unstable gain, operated in UHV
low UV sensitivity, unstable,
not radiation hard, highly visible sensitive
high voltage, 110 nm,
low fluxes, dark current
Ideal UV detector for space
visible blindnessvery low noise
high sensitivity to XUV photonschemical stability
radiation hardness
Requests
Specifiche per i rivelatori del Solar Orbiter
• Solar blindness < 10-7
• Operating temperature ± 50°C• Frame rate 1000 s -1
• Frame format 2K 2K • Pixel size < 20 m• Radiation hardness 50 Krad• Weight 1 kg
Common specification requirements for the imaging and spectroscopic instruments for remote sensing are
Photon fluxes (counts/s/px)
Imaging 103
Spectroscopy 102-103
3-D spectroscopy 105
Photon fluxes (counts/s/px)
Imaging 103
Spectroscopy 102-103
3-D spectroscopy 105
Rivelatori UV disponibiliPhoton Counting
MCP + XDL
MCP + APS
MCP + CID
Advantages Photon counting Solar blindness Radiation hardness Spatialised Operating @ Tamb
Disadvantages Efficiency < 30% High voltage biases Weight Spatial resolution (centroid
required) External electronics (to be
shielded!)
Charge integration
None!
CCD is not rad-hard
Alternativa: nuovi materiali fotosensibili
Eg = 5.5 eV dark current < 1 pA
visible rejection (ratio 10-
7)
high EUV sensitivity Highly radiation hard Chemical inertness Mechanically robust (high Young modulus) High electric charge mobility = fast response time Low dielectric constant = low capacitance
Diamond & nitrides are appealing materials for the EUV photon detection. Their main properties are hereafter sumarized :
Rivelatori a diamanteDevice area: 6 6 mm2 Thickness: 40 µm Grain size: 20 µmSensitive area 4 mm2
Interdigitated contacts
spacing 20 mthickness 0.1 melectrode width 15 m No thermal annealing
back contact 25 mm2
Dark current
-200 -150 -100 -50 0 50 100 150 200-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Au
Voltage (V)
Cur
rent
(pA
)
Stabilità e risposta temporale
-200 0 200 400 600 800 1000120014001600
0
20
40
60
80 36 KV/cm
28 KV/cm
20 KV/cm
Pho
tocu
rren
t (nA
)
Time (s)
0 20 40 60 80 100 120 140 160 180 200
0,0
0,2
0,4
0,6
0,8
1,0
1,2
20 KV/cm 28 KV/cm 36 KV/cm
Nor
mal
ized
Pho
tocu
rren
t
Time (s)
Toff = 30 %
Quantum Efficiency
200 400 600 800 10001E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
0,1
1
10
100
E = 28 KV/cm
Ele
ctro
n / p
hoto
n
Wavelength (nm)
100 120 140 160 180 200 220 240 2600,01
0,1
1
10
100
1000
10000
QE Diamond QE CCD QE MCP + KBr
Qua
ntum
Effi
cien
cy (%
)Wavelength (nm)
[1] Naletto, Pace et al, 1994
[2] Wilhelm et al.,1995
[2]
[1]
Diamond efficiency Comparison with other detectors
E. Pace et al., Diam. Rel. Mater. 9 (2000) 987-993.
Diamond – Responsivity
-200 -150 -100 -50 0 50 100 150 200-1,2
-1,0
-0,8
-0,6
-0,4
-0,2
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
Voltage (V)
Cur
rent
(pA
)
Dark current @ room temperature
Vbias = 30 V
Our proposal: flip-chip CMOS imager
Select the most appropriate sensitive material
Exploit the advantages offered by the CMOS technology to fabricate system-on-a-chip detectors
Join the best material and on-chip CMOS electronics by means of the consolidated flip-chip technology (applied to IR photon and particle detection)
The idea
Diamond bump-bonded detector
Incident radiation
Open electrode
CMOS imager
Sensitive layer
Pixel array
12.5 m
Applicazioni attuali Applicazioni attuali
alla fisica delle particellealla fisica delle particelle
Advantages of flip-chip technology
High responsivity Visible rejection Available technologies Frame format and pixel size in the spec On-chip read-out electronics Radiation hardness Compact detector (reduced weight) Low power consumption High frame rate Windowing
EUV sensitive layers bump-bonded on CMOS imagers could have many appealing features, such as:
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