Detector technological development and Balloon Test

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• Detector technological development and Balloon
  Test
• (3D Spectroscopic Italian CZT detectors RD
  status of the art)
• E. Quadrini, E. Caroli
• On behalf of a large consortium

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Why CZT detectors?
Competitive performances
(resolution time, space, energy, stopping
power) Good performances at environmental
conditions (no cryogenics
or pressurization) High stability in Time
(simplified design and control) High
linearity versus Temperature and Bias
(simplified data
analysis) Direct photon-signal conversion
(no optical contacts, fibers ,glues
higher efficiency) Soft Gamma Ray Range
(from 10 to 400 keV) Flexibility
( Many
configurations trough photo-lithograph
process) Modularity
(cm2 to m2 focal
plane) Wide applicability
(all non destructive/not invasive
inspections in many fields
medical, security, custom,
metallurgic, building)
Potential Italian detectors source low cost
customization, easy procurementand planned
development time 2 years, for the following
Target for an end to end domestic CZT detector
system Resolution Space lt mm in 3D Time
few tens of µs Energy 2 _at_100keV Energy
range 7- 400keV single layer ?Compton
structures under evaluation Efficiency
80 up to the MeV region
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• The RD activities have been financed by
• ASI 200k RD study Dec 06 to July 07
• INAF 80k PRIN 2007-2008

Scope To evaluate the Italian Industry interest
for a medium-large scale production
of enhanced 3D spectroscopic multi-anode CZT
detectors. The goal is to provide a friend
source for applications in Space science research
as well as for numerous devices for
non-destructive inspections on ground.
DEVELOPMENT LINES CRYSTAL GROWTH surface
treatment, metallization bonding- contact,
detector characterisation 3D INTERACTION POINT
RECONSTRUCTION On PPF Fast Signal AD
conversion, Energy digital construction On
PTF N-anode plus orthogonal N-catode
contacts, for n2 pixels SCIENCE New
Astrophysics frontiers requirements for X-? new
Instruments INDUSTRY Market Study cost
and production time analysis
Preliminary evaluation
of ASIC for AFEE application
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Involved Institutions and People
CNR IMEM Parma Andrea Zappettini, Eros Gombia
Laura Marchini,
Roberto Mosca Paolo Sanviti,
Lucio Zanotti M. Zha UNI-Parma Maura Pavesi
Massimiliano Zanichelli
INAF-IASF-Milano Egidio M. Quadrini, Monica
Alderighi Fabio Casini, Sergio DAngelo Marcello
Mancini, Mauro Fiorini Nicola La Palombara,
Michela Uslenghi

INAF-IASF- Bologna Ezio Caroli, John B. Stephen,
Natalia Auricchio, Ariano Donati, Filomena
Schiavone, Gianni Landini, Angelo Basili,
Thales Alenia Space Milano Paolo Bastia ,
Arnaldo Bonati Jens M.
Poulsen , Nicoletta Ratti
Venezia Tecnologie Marcello G. Guadalupi
INAF-IASF- Roma Pietro Ubertini, Angela Bazzano
Sergio Di Cosimo Massimo Frutti Memmo Federici
Lorenzo Natalucci
INAF-IASF- Palermo Stefano del Sordo, Gaetano
Agnetta, Giovanni La Rosa, Benedetto Biondo,
Francesco Russo, Angelo Mangano
Foreign Partners Portugal (Univ. of
Coimbra) Denmark (DNSC, Copenaghen) Spain
(Barcellona)
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CZT development RD Study. End of first phase
results
2006 1 inch monocrystal
CRYSTAL GROWTH
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Typical detector I/V curve
Detector response November 2006
FWHM 7keV _at_17 keV 9keV _at_60 keV
A.Zappettini CNR-IMEM
N. Auricchio, E. Caroli INAF-IASF-Bo
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CZT development RD Study. First phase results
Today
Electronics Read out evolution
Yesterday
Tomorrow

• Detector and ASIC are assembled to constitute one
  single module
• 0.35 ? m CMOS technology
• Complete integration from preamplifier to the A-D
  converter for 256 pixels

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CZT development RD Study. First phase results

• Digital sampling from pixel (red) and cathode
  (black) signals _at_ f100MHz
• Signal classification vs rt ?10-90
• Peak analysis _at_ 122/136 Kev vs ?
• Signal energy loss vs ?
• Signal amplitude correction

Co57
S. Monti Master Degree Thesis
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CZT development RD Study. First phase results
Pixel signal, anode
57Co
122 keV
136 keV
S. Monti Master Degree Thesis
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• Requirement for next generation of Focal Plane
  detector in high energy focussing telescope
• High efficiency ( 80) up to the MeV region
• Moderate spatial resolution (1-3 mm)
• 3D sensitivity to photon interaction position
  for Polarimetry and Background rejection
• Good spectroscopic resolution (few at 100 keV)

• Detector material suitable for fulfilling the
  requiremements CZT
• To achieve high efficiency even with an high Z
  material like CZT, several cm of thikness are
  needed Stack detectors
• We have proposed a focal plane detector
  configuration that could allow to reach several
  cm thickness without increasing to much the
  numbers of layers and pixels (i.e. electronic
  channels) coupling two basic ideas
• PTF irradiation configuration for the single
  sensitive units
• Drift strip configuration for anode electrodes

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• PTF irradiation configuration for the single
  sensitive units.
• This irradiation configuration have been proposed
  several years ago by the Solid State group at the
  INAF/IASF-Bologna (ex TESRE).
• PTF Photon Transverse Field the field is
  perpendicular to optical axis
• The photon absorption thickness is independent
  from the charge collection distance. The
  charge collection efficiecy is independent from
  energy.
• Thickness for photon absorption is limited by
  ingot quality Today 2 cm are feasible

Drawback all the distances between collecting
electrodes are uniformly hit by radiation.
Therefore the effect of the charge collection
efficiency difference play a more important role
in the detected energy spectra. (right) the two
spectra have been normalized to main peak (122
keV) counts.
PPF
PTF
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Drift strip configuration for anode
electrodes. This electrodes configuration have
been proposed and studied by the colleagues of
the DTU Space (ex DNSC) in Copenaghen to improve
the spectroscopic resolution of CZT detectors.
Comparison between energy spectra obtained with
standard planar and drift strip devices (same
crystal geometry). The achieved energy
resolution is 4 at 60 keV (top) and 3 at 122
keV (bottom)
Electrodes drift configuration for a 10x10x3
mm3, 0.2 mm pitch anodic strips (top) Model of
the electric field inside a drift cell (bottom)
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Small 3D CZT position sensitive
spectrometer Approved by INAF as PRIN 2007
project (2 years) 4 INAF/IASF institute with
the IMEM/CNR in Parma.
The linear module. Each contain 2 CZT (yellow)
units and 16 CSP (brown) chains on a thin
Alumina support
Basic sensitive CZT unit anode (L) 32 strip of
0.15 mm , cathode (R) 4 strip of 2.4 mm
The 3D detector prototype packaging scheme
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Way an Italian Detector source?
In most of cases when a multiple event is
reconstructed the events energy sum is smaller
than the impinging photon energy
Part of carriers falls in the inter-pixel gap
SOLUTIONS, AT A REASONABLE COST, BY A FRIEND
SOURCE To reduce as much as possible the
inter-pixel gap To optimise the electrical field
through auxiliary grids To realise an effective
drift detector with a proper electrode design
S. Monti Master Degree Thesis
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Way an Italian Detector source?
Few exempla for
A FLEXIBLE BASIC CRYSTAL Many solutions easily
implemented, e.g. L 12 x 12 mm 16
pixels pitch 3 mm S 12 x 12 mm 64
pixels pitch 1.5 mm Color code gray
substrate red polarization
grid blue cathode
L
S
A friend detector source, will allow to decide
time by time the proper pixels size, the crystal
thickness, the inter-pixel gap the polarization
field shape. All options from classic small
pixels, to real drift detectors can be
implemented at a reasonable cost.
INAF-IASF-MI
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Way an Italian Detector source?
EVALUATION OF COST (JULY 07) AND PRODUCTION TIME
A range from 10 to 100 crystal per 2 CZT ingot
has been assumed
With manpower cost , (220.5 h x 75/h)
we extimate from a min of 183 to
a max of 1830 each multianode detector
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Next steps An arctic balloon long flight with
SIDERALE (Sistema Integrato Di Elaborazione e
Rivelazione per ALte Energie) PI Monica
Alderighi INAF-IASF-Mi
Objective Validate the system in severe
environmental conditions similar to space, as
far as radiations are concerned in a long
duration flight Discriminate photon events from
charge particles background events Optimally
reconstruct the event energy Evaluate pixel
detector spectroscopic capability in presence of
high irradiation in a cosmic-ray dominated
environment Estimate the local background in
the 10-400 keV range as a pathfinder for new
experiments or tests Minimal System survival in
nominal conditions for the expected flight
duration
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Siderale Budgets
Power
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SIDERALE as an opportunity to test in a long
duration balloon flight the new ASI Telemetry
systemSTRADIUM
The small payload SIDERALE could represent an
effective test of the STRADIUM TLM system in
operational condition on board of a long duration
stratospheric balloon flight. SIDERALE in fact
require both on board data recording, downlink of
both scientific data and payload housekeeping
data and simple telecommanding operation.
The STRADIUM main features fulfil completely the
SIDERALE requirement. In particular STRADIUM have
built-in the possibility to record data
continuously on a solid state device (flash
memory) while a selectable percentage
(programmable inside the TLM system) can be
transmitted to ground with the 2048 bit/s
band. Furthermore the STRADIUM power interface
will allow to have a stable bias (/-12V up to
300 W) from which the SIDERALE payload could
easily derive the needed bias for detector and
electronics operation whithout caring about the
original source. Easy ground operation of the
payload through the available STRADIUM quick look
with the integrated network access.
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Possible flight plan for future prototypes

• The realisation in a two years time of the INAF
  PRIN 3D CZT small prototype and and the
  contemporaneous realisation of a thin (5 mm
  thick) CZT detector of almost the same
  geometrical area by our colleagues of the
  University of Coimbra (Portugal), let us allow to
  foresee for in the next 2-4 years a plan for a
  couple of balloon test flight in different
  configurations
• 3D CZT small prototype
• CZT Stack prototype (Coimbra thin detector 3D
  CZT small prototype)
• Italian detectors system can be used as well if
  the RD study will be re-financed

• Both the following flight scenarios are suitable
  for scientific-technological balloon tests
• Antartic long duration balloon flight to asses
  the reliability, the hardness of the proposed
  detector configurations in a high charge particle
  radiation environment as well as to evaluate the
  effectiveness of the 3D events reconstruction in
  background rejection.
• Low latitude ballon flight (e.g.
  trans-mediterranean) for evaluation on the
  diffuse and intrinsic X and gamma ray background
  over a wide band (30-1000 keV) at 3mbar before
  and after the implementation of the 3D
  reconstruction technique.

The dimension/weight and the requirement in power
and TLM of both the proposed detector
configurations will be compatible both with small
volume balloon flight and/or as hosts in
multipurpose payload
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CONCLUSIONS
astrophysic
We are working to improve images and spectra in
the energy range from 10 to 1000 keV and above
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Thank you
Thank you
INAF-IASF-MI