Sezioni INFN: Pisa, Padova, Roma2

1
Pisa, 30 June 2005
IEEM (Ion Electron Emission Microscope)
responsabile locale Massimo Nigro

• Sezioni INFN Pisa, Padova, Roma2
• Linea di ricerca studio di Single Event Effects
  (SEE) indotti da
• ioni energetici in dispositivi e sistemi
  micro-elettronici per
• applicazioni spaziali e fisica delle alte
  energie.
• Laboratorio e facility INFN Legnaro, Tandem XTU
  da 15MV,
• linea di irraggiamento SIRAD con ioni pesanti.
• Processo fisico correlazione su scala
  micrometrica tra
• i punti di impatto ionico e SEE indotti in vari
  dispositivi
• (ASIC, commerciali, strutture di test)
• usando un
• microscopio ad emissione di elettroni secondari
  da impatto ionico

2
nuclear microprobe vs IEEM
Nuclear Microprobe Analysis
Ion Electron Emission Microscopy
Ion beam
2D electron detector at focal plane of electron
optics
(Xhit,Yhit)
object slit
Nuclear Microprobe focusing (e.g. triplet) and
scanning system
?
secondary electrons
Ion beam
electron optics
(Xbeam,Ybeam)
rastering pattern
hit confirmation by detecting secondary
electrons (e.g. channeltron)
coating
analysis of signal
target
analysis of signal
target
Resolution on target determined by beam optics
spot size and positioning. Difficult to
micro-focus all SIRAD ions e.g. rigidity of a
300 MeV Au25 ion is 1.40 T-m, 1.7 times more
than 95 MeV C6 ion. Requires disruptive and
expensive upgrade of SIRAD beamline and of
controls of Tandem Optics!
The ion impact position is determined by
reconstructing the position from which secondary
electrons are emitted. Resolution on target
lateral size of field of view divided by linear
line pair resolution of sensor.
analysis SEE mapping, Ion Beam Induced Charge
Collection, Time Resolved IBICC,...
3
E-fields to manipulate electrons emitted from
irradiated surface
incoming ionizing radiation (photon, ion)

• Electron Emission Microscope collects and
  transports the secondary electrons emitted from
  the irradiated target onto a focal plane.
• A Multi-Channel Plate (MCP) multiplies the
  number of electrons to obtain measurable signals.
  
• Measuring the position of these electrons gives
  the impact position of the radiation quantum.

?
axial symmetry
Aberrations controlled by a contrast diaphragm
with 300?m diameter aperture. Intrinsic
resolution of IEEM 0.6?m over a field of view
of 250?m
collection transport detection
4
From electrons to position information

• A fast and high resolution sensor is required
  for time resolved imaging capabilities.
• By converting the electron signal into photons
  one can place the final sensor off-axis.
• For optimal axial configuration (?0o) the MCP
  must be annular (a central hole) to allow
• passage of the ion beam.

• SENSOR requirements
• High resolution (gtintrinsic IEEM resolution of
  400 points on detector diameter)
• Fast! For SEE and time-resolved IBICC
  applications need gt103 frames/second (Poisson!)

5
schematic of axial (?0o) SIRAD IEEM
system(with novel bi-linear sensors)
6
IEEM June 2004
axial IEEM chamber (Pisa)

• progetto finito
• chiesti preventivi
• offerte entro luglio
• consegna entro dicembre

3 movimentatori micrometrici (Padova) consegnati
supporto preliminare camera IEEM (Pisa)
preliminary
Sistema specchio (Pisa)
Vassoio/cassetto per accesso completo
IEEM
Specchio inclinabile
Sistema specchio (Pisa)

• progetto finito
• chiesto offerte dei pezzi
• assemblaggio a Padova
• entro ottobre

MCP anulare (Padova) In attesa di consegna
oblorientrato per aumentare efficienza ottica!
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IEEM June 2005
ritardo totale 1 anno

• ritardo iniziale (qualche mese) per
  aggiornamento del progetto
• a valle del finanziamento INFN
• grossi ritardi consegne su items strategici
• MCP anulare consegnato dicembre 2004 (9 mesi
  dallacquisto),
• camera IEEM consegnato marzo 2005 (8 mesi
  dallacquisto)
• ? saltato flow chart
• ? nuove interferenze con lavoro su SIRAD
• (presa dati upgrade tra july-sept 2005)
• qualche errore ahimè!

Beam
new SIRAD chamber under construction
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IEEM INFN/Pisa

• NEW axial IEEM
• chamber
• NEW final support
• READY!

Camera e supporto finale (tasks del 2004)
consegnati (marzo 2005!). Siamo in attesa di
installazione in coordinazione con lavori di
upgrade di SIRAD! N.B. linea SIRAD attualmente in
presa dati.
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IEEM INFN/Pisa
10
IEEM INFN/Padova
CCD camera
working non-axial IEEM with NEW improvements
beam splitter (NEW)
PSD
old SIRAD chamber
image intensifier
ions
NEW mirror system!
old PEEM chamber
IEEM
sub-?m motors
IEEM
UV lamp
NEW
NEW annular MCP!
11
Ion electron emission images of a Cu grid NOTE
event rate in field of view 500 Hz
split Image. Individual events resolved in time
reconstructed by charge division using a
semiconductor PSD.
conventional Image by a normal CCD camera
(practically no time resolution)
same!
Bromine 250 MeV
spurious electron emission from back plane
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Sensing Possibilities analog VS digital

• Position Sensitive Devices working on the
  principle of charge division
• pixel-like detection (e.g. CCD arrays)

• Slow and not so easy to read
• Resolution independent from charge (above
  threshold Level)
• Insensitive to environmental noise
• Extremely high resolution possible (more than 1M
  pixels)

• Fast and relatively easy to use
• Resolution depends on charge!
• Sensitive to environmental noise!!

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Digital Sensing square array VS two linear arrays
How to continuously read 10002 pixels some 104
times per second?
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IEEM INFN/Padova
bi-linear Digital Sensing status summary
NEW optics
NEW annular MCP and fast-signal electronics
IEEM and NEW mirror system
DAQ and processing board
2 orthogonal linear CCDs (soon NMOS)
Takes less than 30µs to happen (99 is due to
CCD/NMOS reading!)
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IEEM 2006 (continuazione) struttura, FTE, tasks
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IEEM 2006 (continuazione) chiediamo 34 kEuro