Active Macro Pixel Sensor Array - Helsinki Institute of Physics

Progress with
Active Macro Pixel Sensor Arrays
for X-ray X
Imaging Spectroscopy
Heike Soltau, P. Lechner, L. Strüder et al
PNSensor GmbH Munich
MPI Semiconductor Laboratory Munich
IWORID 2008, Helsinki

Spectrometric Parameters
• energy range
100 eV to 20 keV
Active Macro Pixel Sensor Arrays
are attractive • high quantum efficiency
with thin entrance window
because they allow
and depleted volume of 450 µm
–• monolithic minimum devices signal capacitance
in large formats up to 8 x 8 cm²
of 20 fF only
– with scalable pixel size
• energy e.g. 300 resolution x 300 µm² down to to 1 x 1 mm²
– charge 50 storage eV @ C capability K
in contrast to a CCD
125 eV @ Mn K
–
•
line
image
readout
(frame)
on demand
rates
with a limited complexity
up to 8.000 per sec
and a high speed
• low electronic noise at high rates
10 el. ENC
• radiation hardness
Active Macro Pixel Sensor Arrays

Active Pixel with DEPMOSFET Amplifier
The pixel is
made up by
• topology
• internal
amplification
• charge storing
capability
• integrated
reset FET
Operation Mode
fully depleted
volume of Si
usually OFF
p+ back FET ON contact
and internal drift rings gate
internal Measure gate exists I ds
Clear in ON Internal and OFF Gate
deep state Measure MOSFET n-implantation
of the IFET
ds
p-channel ⇓ on
n-type low power
current bulk
local change potential prop.
consumption
to number minimum with of electrons
internal for electrons gate
and clear gate
DI > 300 pA / electron

From Active Pixel Sensors (APS)
to Active Macro Pixel Detectors
Macro Pixel Detector which is mainly
a DEPFET surrounded by Drift Rings
allows
9 monolithic assembly of large areas
9 with minimum number of pixels
of individually addressable pixels
in arbitrary size
9 homogenous backside
with a fill factor of 1
keeping the good properties of the APS
9 low noise
9 low power consumption
9 fast processing etc.

Active Macro Pixel Sensor Array
readout sequence
matrix operation
• 1st measurement: signal + baseline
• clear: removal of signal charges
• 2nd measurement: baseline
• difference = signal
• complete clear is mandatory
• horizontal supply lines, row selection
• vertical signal lines
• 1 active row, other pixels integrating
option to speed up (1)
• readout parallelisation
• 2 x readout channels, 2 active rows

Active Macro Pixel Sensor Array –Read Out
CAMEX64 readout chip
• 64 channel amplifier
• source follower configuration
• 8-fold CDS filter
• 64/1 analog multiplexer
• readout time / row 4 µsec
option to speed up (2)
2 x SWITCHER-II control ASIC
• 64 channel control chip
• 2 ports / channel
• supply of switched voltages
• extremely low noise level
• high voltage CMOS process > 20 V p-p
• 50 MHz clock
• "VELA" readout chip by Politecnico di Milano
drain current readout
current (de)integration filter
readout time / row = 2 µsec

Application I
Low Energy Detector (LED) for Simbol-X Mission
Joint French-Italian project
German participation: - mirror calibration
- Low Energy Detector
1 st focussing hard X-ray telescope
ranging between 0.5 keV .. 20 keV .. 80 keV
science targets
• census and physics of black holes
• cosmic particle acceleration
mission scenario
• launch mid 2014 (Soyuz-Fregat/Kourou)
• autonomous formation flight
• life time 3 y (+ 2y)
• pointings 1000 (+ 500)
• science time
instrumentation
• low energy detector LED
> 100 Msec
• high energy detector HED

Application I
Macro Pixel Sensor for Simbol-X –Design
Focal Plane Sensor
• monolithic 6" wafer scale device
• pixel size 625 x 625 µm²
• format
128 x 128 pixels
8 x 8 cm²
• quadrant divison
individual r/o & control:
8 x CMX, 8 x SW2
• FP power
< 8 W
Readout Modes
• full frame
CCD-like, bi-directional
full frame time = 128 µsec
frame rate = 8.000/sec
• window mode
window size 2 x 16 rows
no additional hardware
window time = 32 µsec

Application I
Macro Pixel Sensor for Simbol-X –Status
Simbol-X LED demonstrator
• pixel
• format
• frametime
500 x 500 µm²
64 x 64 pixels
3.2 x 3.2 cm 2
2 msec
• temperature -80 … -90 °C
• represents 1 quadrant
of the flight detector

Application I
Macro Pixel Sensor for Simbol-X –Spectroscopy
Spectroscopic Results
• flat field illumination
• energy resolution
(FWHM @ 5.9 keV)
127 eV (singles)
135 eV (all events)
• peak/background ratio
3.000:1 10.000
• pattern statistics
63% singles
29% doubles
• (in)homogeneity
0.3% offset
2.3% gain
9.6% noise

Application II
Wide Field Imager (MIXS-C) for BepiColombo
Mercury Planetary Orbiter
•to investigate the average composition
of Mercury’s crust, the composition inside craters
and the distribution of iron globally and locally
Mission scenario
•Launch 2013
•Platform: Soyuz Fregat B
• Scheduled arrival at Mercury: 2019
•1 + 1 year of expected mission lifetime
Instrumentation
•very diverse
•including the X-ray Spectrometer MIXS
in the focal plane of the observatory
X-ray Detector Format
•Active area: 1.92 x 1.92 cm2
•Pixel number: 64 x 64 pixels
• Pixel size: 300 x 300 um

Application II
Macro Pixel Sensor for Bepi Colombo –Design
Pixel number: 64 x 64 pixels
Pixel size: 300 x 300 um
Active area of 1.92 x 1.92 cm 2
Number of drift rings per pixel: 3
Max. drift ring voltages ~30-40 V
No sensitivity gap between pixels
Challenge
Radiation damage of 3 x 10 10
10 MeV protons /cm 2
Detection of low energies like Fe_L

Application II
Macro Pixel Sensor for Bepi Colombo –Read Out
N
W
S
E
2 Hemispheres (North and South)
32 x 64 Pixels each
Read out by 1 CAMEX each
Controlled by 2 Switchers each
Readout speed: target 4 ms / row
6 ms / row might be necessary
Depends on FE performance,
temperature, capacitance...

Application II
Macro Pixel Sensor for Bepi Colombo –Prototype
CAMEX
Switcher
Switcher
Switcher
Switcher
CAMEX

Thank you!
60
Row number
50
40
30
20
20,00
128,0
236,0
344,0
452,0
560,0
668,0
776,0
884,0
992,0
1100
10
10 20 30 40 50 60
Column number
• shadow images of a 450 µm thick silicon mask
using an 55 Fe source
• statistics: ~ 5.000 frames
• defect-free: no dark pixel, no bright pixel