Wide Field Imager

Readout ASIC DevelopmentVERITAS II

Garching, 28 January 2014

Matteo Porro

Wide Field Imager

Focal Plane ASICs

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256 x 256

Switcher ASICs Steering of DEPFET Arrays (Row-select; Pixel

reset) Provided so far by Heidelberg University Heidelberg would be a natural provider for the

future

Readout ASIC So far partially or completely developed at

MPE/HLL MPE has the expertise in low-noise readout The existing ASTEROID ASIC will be used for

MIXS of BepiColombo VERITAS ASIC is being developed for ATHENA

Readout ASIC

Switcher ASIC

Example of DEPFET prototype focal plane arrangement

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ASIC Filter Filter architecture pnCCD DEPFET SF

DEPFET CR

Dynamic range

CAMEX MCDS Unipolar, single-ended, two stages low*, high**

VELA1 Trapezoidal Unipolar, single-ended, two stages low

ASTEROID1 Trapezoidal Unipolar, single-ended, two stages low

VERITAS 1.0 Trapezoidal Unipolar, single-ended, two stages low, high

VERITAS 2.0 Trapezoidal bipolar, fully differential, single stage low, high

1In collaboration with Politecnico di Milano, L. Bombelli and C. Fiorini

XMM-Newton and FEL experiments pnCCD with CAMEX BepiColombo DEPFET array with ASTEROID

*Synchrotron and FEL applications** Spectroscopy, X-ray astronomy, fast optical astronomy.

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DEPFET Readout ASICsMAIN CHARACTERISTICS AND FEATURES

Row-wise readout (parallel readout of all the pixels in one sensor row)

Analog Multiplexing

Biasing of DEPFET arrays

Two possible input stages for:

Source Follower readout AC coupling -> easy to operate Long settling time

Drain Readout bias current cancellation required Very short settling times

Optimum analog shaping (trapezoidal Weighting function)

Window mode

Wide Field Imager

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ASTEROID for BepiColombo

55Fe

T=-60 °C

Mn-Kα

0.9µs integration

clear settling

Source Follower readout

Total readout time: 4.8µs (1+0.9x2+2)

Effective signal processing time 1.8 s

energy resolution (FWHM @ 5.9 keV)

124.8 eV (singles)

128 eV (all events)

peak/background ratio 3.000:1

Asteroid

Asteroid

Wide Field Imager

VERITAS II ASIC

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Analog section(64 ch.)

4.6 mm

6.9 mm

S&H and MUX

SPI control& SRAM

AMS CMOS 0.35 mm 3.3 V

Two readout modes:Source Follower Readout / Drain Readout

Targeted readout time per row with drain readout ~ 2.5 s

Fully differential architecture

64 readout channels

MUX 64:1 – design speed 32 MHz

Total power ~400-500 mW

Can be used also with pnCCDs(The use of the ASIC by different groups is beneficial for fast development)

First version is available and is under test

Wide Field Imager

Results with SF are comparable with those obtained with ASTEROID

The non-optimal resolution is due to the used DEPFET

Investigation of the drain readout is ongoing

An optimized redesign is foreseen in one year

Bug fixing Optimization of parameters for ATHENA

requirements Possible additional features

Mn-Kα

55Fe

T=-60 °C

Preliminary results and outlook

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References

M. Porro et al. "VERITAS: A 128-channel ASIC for the readout of pnCCDs and DEPFET arrays for X-Ray imaging, spectroscopy and xfel applications", IEEE Transactions on Nuclear Science, vol. 60, no. 1, pp. 446-455, 2013

P. Majewski et. al, "DEPFET macropixel detectors for MIXS: Integration and qualification of the flight detectors", IEEE Transactions on Nuclear Science, vol. 59, no. 5 PART 3, pp. 2479-2486, 2012

A. Meuris et al. "Development and characterization of new 256 × 256 pixel DEPFET detectors for x-ray astronomy", IEEE Transaction on Nuclear Science, vol. 58, no. 3 PART 3, pp. 1206-1211, 2011

M. Porro et al. "ASTEROID: A 64 channel ASIC for source follower readout of DEPFET arrays for X-ray astronomy", Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 617, no. 1-3, pp. 351-357, 2010

M. Porro et al. , "Spectroscopic performance of the DePMOS detector/amplifier device with respect to different filtering techniques and operating conditions", IEEE Transactions on Nuclear Science, vol. 53, no. 1, pp. 401-408, 2006

E. Gatti, et al., “Optimum filters for detector charge measurement in presence of 1/f noise,” Nucl. Instrum. Methods A, vol. 287, pp. 513–520, 1990