Evolving SDD to advanced light sources
Sergio Fabiani a,
M. Ahangarianabhari c,f, P. Bellutti h, G. Bertuccio c, f, M. Bruschi i, J. Bufon b,e, S.
Carratoe, A. Castoldim, G. Cautero b, A. Cicuttin l, M. L. Crespo l, G. Giacomini h, A.
Gianoncelli b, D. Giuressi b, M. Grassid,g,C. Guazzonif, D. Macera c,f, P. Malcovati
d,g, R. H. Menk b, A. Picciotto h, C. Piemonte h, I. Rashevskaya a,A. Rachevski a , A.
Sbrizzi i, A. Vacchi a , G. Zampa a , N. Zampa a, L. Olivib
a
INFN Sezione di Triste, Trieste, Italy
bElettra-Sincrotrone Trieste S.C.p.A.,
Trieste, Italy
cPolitecnico di Milano, Como, Italy
dUniversità di Pavia, Pavia, Italy
eUniversità di Trieste, Trieste, Italy
fINFN
Sezione di Milano, Milano, Italy
gINFN Sezione di Pavia, Pavia, Italy
hFondazione Bruno Kessler,, Trento, Italy
iINFN Sezione di Bologna, Bologna, Italy
lICTP, Trieste, Italy
mPolitecnico di Milano, Milano, Italy
• The starting point
• TwinMic
• XAFS
The starting point
•
INFN thecnology to design large area linear SDD
• Designed to provide 2D tracking of ionizing particles with very good resolution in a
high-multiplicity environment with a very limited number of channels
• linearly scaling potentials are applied to drift cathodes to generate a constant
electric field parallel to the detector surface directed outwards an array of anodes
• the first coordinate is determined by the
center of gravity of the signal at the anodes
• the second coordinate (drift axis) is
determined measuring the time required
by the electron cloud to reach the anodes
• due to their collection electrode geometry,
SDD have excellent noise performance
and are well suited for low-energy
X-ray spectroscopy applications
Improvements…
• Capability to design new gometries to match different needs (scientific
requirements, volume occupacy …) in collaboration with FBK (Trento)
• Development of new low-noise dedicated electronics (Politecnico di Milano)
also for high rate experiments (INFN Sezione di Bologna/CERN).
SDD for Elettra
Development of new customised
detectors for two syncrothron
beamlines at Elettra:
- TwinMic: larger collecting
area as possible within the
vacuum chamber volume
limitations
- XAFS: fast acquisition and
dead time reduction
In both cases the reduction of
integation time of
measurements is the goal to
allow the sevice facilities to be
competitive.
TwinMic @ Elettra
• TwinMic is worldwide unique in
combining transmission imaging,
absorption spectroscopy and lowenergy X-ray Fluorescence, which
allows for analyzing simultaneously the
morphology and elemental or
chemical distribution of specimens
with sub-micron resolution in the 4002200 eV energy range.
Low Energy X-ray
Fluorescence (LEXRF)
Spectroscopy detector to
upgrade with a novel Multicell Silicon Drift Detector with
trapezoial shape.
TwinMic @ Elettra
LEXRF PRESENT STATUS
• 4% photoemission solid angle
• Low Count Rate 10 kHz
• 8 single cell SDD (7 x 30 mm^2, 1 x 20
mm^2)
• 127 eV energy reolution at 5.9 keV
(Ka Mg)
TwinMic @ Elettra
• 4 trapezoidal detectors
• Increase to 40% of the
photoemission solid angle
(factor of 10)
TwinMic @ Elettra
TwinMic @ Elettra
• Some preliminary measurements peformed
• Optimized deicated electronics under development (Elettra/Politecnico di Milano)
TwinMic @ Elettra
First light below 2 keV:
beam scattering 2 keV
Al 1.5 keV
down to 677 eV of F
XAFS @ Elettra
XAFS at Elettra is the Italian beamline dedicated to x-ray absorption
spectroscopy. It is installed on a bending magnet source.
Detector position
forTransmission
measurements
Target
Detector is behind the
box for fluorescence
measurements
Radiation
beam
XAFS @ Elettra
Beam line
• Beam photon flux on the target
• Target
10 − 10 ph s-1 mm-2
solid ~ few cm2, also
liquid in a box few cm of
side (element to measure mixed in a matrix)
• Target position with respect to the beam 45° for fluorescence analysis
• Energy Range
• Side effects
Detector set-up present status
• Detector
• Geometric area
• Environment
fluorescence analysis in the
2.2 - 27 keV energy range
1) fluorescence from the matrix elements
2) scattering from the set-up
AXAS-M VITUS SDD Series by KETEK
80 mm2 monolithic
Air (Vacuum set-up is coming)
XAFS @ Elettra
At present a complete cycle of measurment can last for 5 hours
and 30 minutes due entially to count rate limitation induced by
dead time
XAF
S
XAFS @ Elettra
IMPROVEMENTS:
• Dead time:
• Detector segmentation
• Fast electronics (preamplification stage in
collaboration with Politecnico di Milano, Flash ADC
with INFN Sezione di Bologna/CERN)
• Collecting area: increase of the geometric area of the
detector (at present a first prototype of 16
cells (9mm^2 each) (2 arrays of 8 cells) will
be tested with the end of 2014 (hopefully) )
• The goal is the reduction of a factor of 10 of the measurement
cycle (about 30 minutes from about 5 hours and half)
Final Remarks
• Within the end of 2014 the updated set-up of TwinMic will be
tested at the beamline
• Hopefully also a «very early» prototype of the new version of
the intrument for XAFS will be tested at beamline within the end
of 2014