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Herrmann Halbleiterlabor – FEE2006 1 Design and performance of the CAMEX readout ASIC of the X-ray pnCCD for the eROSITA mission S. Herrmann a,d, W. Buttler.

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Presentation on theme: "Herrmann Halbleiterlabor – FEE2006 1 Design and performance of the CAMEX readout ASIC of the X-ray pnCCD for the eROSITA mission S. Herrmann a,d, W. Buttler."— Presentation transcript:

1 Herrmann Halbleiterlabor – FEE Design and performance of the CAMEX readout ASIC of the X-ray pnCCD for the eROSITA mission S. Herrmann a,d, W. Buttler b, R. Hartmann c,d, N. Meidinger a,d, M. Porro a,d, L. Strueder a,d a Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Garching, Germany b Ingenieurbuero Werner Buttler, Ueberruhrstr. 476, Essen, Germany c PNSensor GmbH, Roemerstr. 28, Muenchen, Germany d MPI Halbleiterlabor, Otto-Hahn-Ring 6, Muenchen, Germany

2 Herrmann Halbleiterlabor – FEE eROSITA scientific goals e ROSITA = extended ROentgen Survey with an Imaging Telescope Array Main scientific goals: First imaging all-sky survey (1 y exposure time) up to 10 keV with unprecedented spectral and angular resolution. → systematic detection of obscured accreting Black Holes in nearby galaxies and new active galactic nuclei in the hard band. Wide and deep survey (3 y y): observation of dedicated sky regions to detect ten thousands of clusters of galaxies. Follow-up pointed observations (0.5 y) to map out LSS in Universe → nature of Dark Energy and Dark Matter; model of inflation + re-observation of interesting targets

3 Herrmann Halbleiterlabor – FEE eROSITA instrument 7 mirror systems (Wolter-I) each with pnCCD camera in focus → seven fold redundancy ABRIXAS:

4 Herrmann Halbleiterlabor – FEE eROSITA focal plane cameras camera electronics  7 identical pnCCD cameras  passive cooling → radiator (no TEC)  graded shield → background detector requirements:  image area 19.2 x 19.2 mm 2  pixel size: 75 µm x 75 µm  time resolution: 50 ms ↔ frame rate: 20 images / s  energy range: 0.5 keV – 10 keV  quantum efficiency > 90%  energy resolution: < keV  power consumption ≤ 0.3 W  operating temperature [-80°C; -60°C] camera pnCCD housing

5 Herrmann Halbleiterlabor – FEE eROSITA CCD module CCD CAMEX PCB electronics  5 layer aluminum oxide ceramic printed circuit board which carries pnCCD & ASICs and is used as the cooling connection between the cold plate and the detector  polyimid flexlead bonded to ceramic board  rigid pcb at the end of flexlead with connectors and auxiliary electronics (analog signal drivers, CCD pulse generators) passive components

6 Herrmann Halbleiterlabor – FEE frame store pnCCD optimizations for eROSITA pnCCD:  frame store → less OOT events: 0.2%  fabrication process → lower dark current  silicon, 450 µm → better low energy response & QE  smaller read capacitance → better noise performance  HE implant → lower CTI  for space application: suppression of optical and UV light → filter deposited on-chip  new analog signal processor → low noise, high output speed

7 Herrmann Halbleiterlabor – FEE CAMEX analog signal processor  CAMEX ASIC (CMOS Analog Multiplexing): tailor-made for eROSITA CCD  JFET-CMOS process, 5 V, 0.8 µ m  128 readout channels filtered in parallel  1 or 2 analog output nodes (selectable)  8-fold correlated double sampling  internal shift register sequencer  gain & bandwidth of the ASIC can be changed by digital programing (16 gain settings, 8 bandwidth settings)

8 Herrmann Halbleiterlabor – FEE CAMEX block diagram

9 Herrmann Halbleiterlabor – FEE CAMEX signal filtering - MCDS weighting function signal

10 Herrmann Halbleiterlabor – FEE Weighting Functions - calculation of output noise Carson´s theorem Noise with power spectrum N(f) can be described as the random occurrence of pulses with an average rate of  and with the shape n(t) of the inverse fourier transformation of N(f). Campbell´s theorem For calculation of the influence of the noise to the output we calculate the statistical superposition of all possible input signals, which leads to: The various noise spectras can be evaluated by conversion of the weighting function to the according input spectras. Standard spectras considered are white series noise (A1), 1/f series noise (A2) and white parallel noise (A3).

11 Herrmann Halbleiterlabor – FEE CAMEX timing sequence S1-S8 reference samples CCD shift S1-S8 signal samples reset S&H

12 Herrmann Halbleiterlabor – FEE MCDS must be bandwidth adapted Optimum filter for step input signal and white series noise is a triangular or trapezoidal weighting function.

13 Herrmann Halbleiterlabor – FEE S/N for serial white noise – as function of bandwidth and number of samples

14 Herrmann Halbleiterlabor – FEE Measured CAMEX WF IN Vbst Vsss Sin Stst G1 G2 BW1BW2 BW 3 Tst R1

15 Herrmann Halbleiterlabor – FEE CAMEX WF – settling times IN Vbst Vsss Sin Stst G1 G2 BW1BW2 BW 3 Tst R1 1.0MHz : RC=160 ns 220kHz : RC=720 ns

16 Herrmann Halbleiterlabor – FEE Measured CAMEX WF – with reset IN Vbst Vsss Sin Stst G1 G2 BW1BW2 BW 3 Tst R1

17 Herrmann Halbleiterlabor – FEE Measured CAMEX WF – with short reset IN Vbst Vsss Sin Stst G1 G2 BW1BW2 BW 3 Tst R1

18 Herrmann Halbleiterlabor – FEE Measured CAMEX WF – with input switch IN Vbst Vsss Sin Stst G1 G2 BW1BW2 BW 3 Tst R1

19 Herrmann Halbleiterlabor – FEE CAMEX CCD burst readout

20 Herrmann Halbleiterlabor – FEE CAMEX linearity

21 Herrmann Halbleiterlabor – FEE CAMEX bandwidth – over BW Settings typeBW1BW2A1/  CMX1322.5MHz15MHz1.64M DUO MHz10MHz0.715M DUO MHz3.2MHz DUO MHz10MHz DUO MHz2.5MHz DUO MHz2.5MHz DUO MHz2.5MHz 0.195M

22 Herrmann Halbleiterlabor – FEE CAMEX filter efficiency – over BW settings

23 Herrmann Halbleiterlabor – FEE Performance: energy resolution T = -75°C; frame rate: 50 ms; Fe55 low noise + no noisy pixel, + improved CTI: 1-2 x  FWHM Mn-K keV, all events : 131 eV single events: 123 eV) split events up to quadruples

24 Herrmann Halbleiterlabor – FEE Performance: low energy response XMM-Newton: pnCCDeROSITA: frame store pnCCD

25 Herrmann Halbleiterlabor – FEE Performance: overview CCD size256x256 pixel 4 cm 2 image (+ framestore) CCD quantum efficiencyE = [0.3 keV – 11 keV] ≥ 90% (without filter) fill factor:100 % CTI≈ 1 · → ∆S max (256 transfers)/S < 0.3% fast transfer from image to frame store 100 μs CCD charge handling capacity> 10 5 e¯ / pixel readout time: 20 µs per line 5.1 ms per frame 13MPix/s/CCD lab. max. frame rate: ROSITA mission frame rate: > 120/s (for large ROSITA-CCD); 20/s  probability(OOT) = 0.2% readout noise2 e¯ ENC (high gain: 1.8 e ¯) energy resolution (T ≈ -70°C):FWHM(277 eV) ≈ 48 eV P/V ≈ 50 FWHM(5.9 keV) ≈ 131 eV P/V ≈ 4000 eROSITA power consumption in focal plane 0.3 W per detector (eROSITA readout duty cycle) CAMEX power consumption0.64 W per ASIC -> 5mW per channel


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