extp meeting (extp: enhanced X-ray Timing and Polarization mission) Shanghai, 30th March 1st April 2016 MPE's views on SDDs as focal plane detectors for SFA - Overview: MPE HEG space projects XMM-Newton EPIC-PN, erosita, Athena WFI - Our concepts for spectroscopic detectors - Our SDDs as focal plane detectors o principle features details examples
MPE HEG space projects ESA XMM-Newton with PNCCD camera (1999 today) First generation of PNCCDs: developed for X-ray astronomy: XMM-Newton Satellite launch: 1999 Pixel size: 150µm x 150µm (4.1 arcsec) 12 CCDs: 64 x 200 pixels Long term stability of pnccd detector (EPIC-PN camera) aboard XMM-Newton: - all 12 CCDs are still operating - same operating parameters (T = -90 C) - quantum efficiency unchanged - slight radiation damage as expected: CTI FHHM/FWHM < 2eV/155eV/y 1%/y
MPE HEG space projects XMM-Newton PNCCD camera
MPE HEG space projects erosita (extended Roentgen survey with an imaging telescope array) erosita all-sky survey: 4 y (/7.5y) - soft band: 30 x sensitivity of ROSAT - hard band (>2keV): first all-sky survey test of cosmological model (Dark Energy) erosita telescope developed unter responsibility of MPE Wolter-I mirror system: 54 shells PSF: 15 resolution (HEW) on-axis FoV: 1.0 diam. Russian SRG satellite L2 orbit (2017) f=1600 mm 4
erosita PNCCD Detector advanced type of XMM-Newton PNCCD back-illuminated frame-transfer CCD chip thickness (= 450 µm) fully sensitive image: 384 x 384 pixels of 75 x 75 µm 2 size column-parallel: 384 independent channels frame transfer: 0.12 ms CAMEX: analog signal processor readout time: 9 ms time resolution: 50 ms on-board event processing minimiz. heat dissipation ( 80% standby) 0.7 W OOT events 0.2% excellent low energy response
erosita detector: PNCCD erosita CAMEX Multi-layer detector board Flexible lead as I/F to CE Detector housing: Mech. + thermal I/F Graded Z-shield: Be/B 4 C - Al - Cu
MPE HEG space projects erosita with 7 PNCCD cameras on SRG satellite Filter wheel Camera Head Camera Electronics Array of 7 PNCCD focal plane cameras:
Energy resolution 55 Fe spectrum: FWHM(5.9keV) = 131 ev Mn-Kα Mn-Kα Mn-Kβ Al-K Si escape peaks Mn-Kβ Signal spread over up to 4 pixels
Intensity distribution over image area Al-K of X-ray tube (QM_140123_06)
erosita PNCCD detector characteristics Sensor Illumination type Image area Pixel size Readout ASIC Read noise Energy resolution Operating temperature Quantum efficiency Readout time Time resolution PNCCD back-illumination 384 x 384 pixels 75 µm x 75 µm (< 10 arcsec) 128-channel erosita CAMEX (3 ASICs per PNCCD) 2.4 electrons ENC rms FWHM(0.53 kev) 62 ev FWHM(5.9 kev) 140 ev -95 C (best wrt radiation damage) E = 1 kev: 89% (on-chip-filter) E = 5 kev: 99% (on-chip filter) 9.2 ms 50 ms
MPE HEG space projects X-IFU: X-ray micro- Calorimeter E=2.5eV T=50mK Mirror system: f = 12 m Aeff 2 m² at 1 kev Wide Field Imager: unprecedented survey power (FoV = 40`x40`) high count-rate capability (1 Crab) E=[0.2 kev 15 kev] state-of-the-art energy resolution focal plane detectors: DEPFET APS (enhanced type of DEPFET MIXS detector for BepiColombo) WFI consortium with MPE as lead institute extp meeting, Shanghai 30 March 1 April 2016 N. Meidinger, 11 MPE
MPE HEG space projects Wide field imager (WFI) for ESA s Athena DEPFET APS Detectors for WFI on Athena Heritage: MIXS on BepiColombo
Focal plane layout Pointing on large or fast WFI detector Large FoV detector 40` x 40` by 1024 x 1024 pixel Size 14 x 14 cm 2 4 independent + identical quadrants requirement: <5ms/frame <10µs/row 2-side buttable DEPFETs Pixel: 130 µm x 130 µm ( 2.23``) accurate source position reconstruction (splits!) for PSF = 5ʾʾ HEW Control ASIC: 3-port Switcher-A Readout ASIC: VERITAS-2 High count-rate capable detector FoV = 143`` x 143`` Size 8.3 x 8.3 mm 2 64 x 64 pixels subdivided in 2 halves requirement: 80µs/frame 2.5µs/row mounted defocussed 13
Main WFI Requirements / Characteristics Parameter Value Energy Range 0.2-15 kev Field of View 40 x 40 Angular Resolution Pixel Size Large DEPFET detector PSF=5`` (on-axis) 130 x 130 µm 2 (2.2``) 1024 x 1024 pixel (4 quadrants) =14cmx14cm Fast DEPFET detector 64 x 64 pixel (split full frame mode - 2 halves readout) Operating mode Operating time Quantum efficiency (on-chip + ext. filter w. mesh) Energy Resolution Time Resolution full frame Fast detector Large detector Rolling shutter Nonstop possible 20% @ 277 ev 80% @ 1 kev 90% @ 10 kev FWHM(1 kev) 80 ev (end of life) FWHM(7 kev) 170 ev (end of life) 80 μs <5 ms Count Rate Capability Fast DEPFET (defocused) 1 Crab: >80% throughput, <1% pile-up Particle Background (L2 orbit) < 5 10-3 cts cm -2 s -1 kev -1 Lifetime 5 y + extension (launch 2028) 14
Space projects with SDD detectors produced at MPI HLL SDD detectors produced at MPI HLL NASA Mars Rovers: SPIRIT and OPPORTUNITY (01/2004) CURIOSITY (08/2012) ESA's Rosetta (67P/Tschurjumow-Gerasimenko) µrosi on Max Vallier satellite
Our concepts for spectroscopic detectors Features: Ultrapure FZ silicon wafers ( = 150 mm) Double-sided processing permits full depletion of 450 µm Si high QE at high X-ray energies First stage of signal amplification (transistor) integrated on-chip low readout noise Back-illuminated detectors uniform QE over detector area Shallow p-implant of photon entrance window high QE at low energies + high p/b ratio Deposition of on-chip light filter (Al) "no" signal by visual light
Our concepts for spectroscopic detectors Quantum efficiency no on-chip light filter 450 µm Si 300 µm Si Fe-K α
Our concepts for spectroscopic detectors Energy resolution 55 Fe spectrum: FWHM(5.9keV) = 130 ev BESSY synchrotron: FWHM(200eV) = 52 ev Mn-Kα E = 200eV Mn-Kβ Gaussian shape! (measured with erosita PNCCD but similar for the other detectors)
Our concepts for spectroscopic detectors Concept requires adequate process technology developed at MPI HLL Basic spectroscopic detector concepts: - Silicon drift detectors readout node / cell time resolution: µs fastest spectroscopic detector spatial resolution possible by array of SDD cells
Our concepts for spectroscopic detectors - PNCCD full-column-parallel CCD: readout node / ch. time resolution: ms spectroscopic + imaging detector - DEPFET active pixel sensor readout node / pixel CCD-like but even faster + more radiation hard window mode (readout of selected sensor rows)
original concept by Gatti & Rehak, 1983 SDD principle & development depleted volume transverse electric field particle tracking spectroscopy adaptation by Kemmer & Lutz, 1984 uniform back contact = entrance window on-chip transistor HLL, 1993 integration of first amplification stage
Our SDD features SDDs developed and produced at MPI HLL (MPE & MPP + Ketek + PNSensor) Drift rings with njfet in "center" Integration of first transistor on-chip robustness wrt microphonic noise + electrical pickup Small capacitance 35fF low noise level + high count rate capability Depletion voltage -100 V Cell area: 5 mm 2 cm 2 good peak-to-valley ratio 15.000:1 (for SD3 with int. collimator)
SDD features Example: 10 mm 2 SDD, T=-17 C, 1 µs shaping, pulsed reset 1kHz: FWHM(5.9keV) 134 ev @ 10 5 photons / s Array of SDD cells, e.g. 7, 19 or 31 cells SDD 19 x 5 mm² XTRA on XEUS
Concept for HTRS on IXO International X-ray Observatory (IXO) proposal/studies: High Time Resolution Spectrometer (HTRS) 31 SDD cells Time resolution: 10 µs Energy resolution: FWHM(5.9 kev) = 150 ev (T=-40 C, beginning of mission) Detector size: 24 mm diameter, 4.5 cm 2 area Cell size: 14.6 mm 2 Spider web baffle: - for suppression of split events - area coverage: 10%
SDD very radiation tolerant min. contribution of dark curr. (no signal storage like CCD or DEPFET) JFET rad hard X-rays up to 10 13 absorbed photons (Mo-K, 18 kev) w/o degradation of energy resolution protons increase of dark current Extreme example: HTRS/IXO (15mm Al): equiv. 5 10 9 10-MeV proton/cm² in 10 y Model based on exp. results: FHWM(5.9 kev) 250 ev @ T=-40 C end of mission (spec. 300 ev) for A cell =14.6 mm 2 Don t forget: shielding + cooling (depends on orbit extp: LEO 550km, incl. 14 Mission duration: 5 y) SDD radiation hardness HTRS/IXO
Silicon Drift Detectors in Space produced at MPI HLL analysis of chemical composition of surface APXS (Alpha-Particle X-ray Spectrometer) on NASA s Mars Exploration Rovers Spirit and Opportunity landed Jan 04, Opportunity still active (in 2014) APXS on NASA Mars Science Laboratory Rover Curiosity landed August 2012 with Peltier cooler APXS "sniffer" by MPCh, Mainz SDD 10 mm² & Cu244 α-sources APXS on ROSETTA Lander Mars Exploration Rover APXS system (MPCh) rendezvous with comet 67P/C-G (Churyumov-Gerasimenko) Mar04, orbit Sept14, Lander philae 12Nov14 only short period of operation
µrosi on Max Valier satellite Miniature X-ray telescope Eff. area: 4.1cm 2 @ 1.25keV SDD @ T=-15 C
µrosi detector calibration in PUMA @ MPE SDD specs: 450 µm thickness 20 mm 2 active area collimator FWHM(5.9keV) = 128eV @ T=-20 C T=-15.5 C
SFA requirements: E = [0.5keV; 20keV] FWHM(6keV) < 180eV end of life shielding + cooling (depends on orbit) Timing resolution: 10µs 11 SFA units How many SDD cells are necessary per SFA unit? Inner cell(s) for source photons and outer ring for diffuse+instrumental background (large number requires multi-ch. ASIC for readout inst. of discrete compon.) Which cell size is optimum? depends on PSF of mirrors ( cell size tailored to SFA) Technical budgets for SFA camera incl. shielding + electronics? Mass, power, volume, radiator area,
Small SDD cell arrays Gravitas proposal 1 + 4 cells Source photons + background 1 + 6 cells (core of 31 cells for HTRS/IXO) 7 instead of 19 cells (XTRA/XEUS)