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Semiconductor Detector Workshop 2005 Taormina / June 19 – 24, 2005. A pnCCD detector system for high speed optical applications. Robert Hartmann 1 , Hubert Gorke 2 , Norbert Meidinger 3 , Heike Soltau 1 and Lothar Strüder 3 PNSensor GmbH, Römerstraße 28, 80803 München, Germany
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Semiconductor Detector Workshop 2005 Taormina/ June 19 – 24, 2005 A pnCCD detector system for high speed optical applications • Robert Hartmann 1 , Hubert Gorke 2 , • Norbert Meidinger 3 , Heike Soltau 1 and Lothar Strüder 3 • PNSensor GmbH, Römerstraße 28, 80803 München, Germany • Forschungszentrum Jülich, Leo-Brandt-Straße, 52428 Jülich, Germany • Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85741 Garching, Germany
Overview • • Principles of pnCCD • Optical properties • • Detector format and geometry • • Readout and data acquisition • • Measurements and Performance • Summary and outlook
Principles of the pnCCD • Fully depleted 3-phase CCD • Back side illuminated • Cooled to -40º C .. -80º C (typ.) • Small detector capacitance ≈ 25 fF → low noise • One integrated FET per channel • Channel-Parallel-CCD → fast readout • p-implanted registers • High radiation hardness
Overview • • Principles of pnCCD • Optical properties • • Detector format and geometry • • Readout and data acquisition • • Measurements and Performance • Summary and outlook
pnCCD for optical applications • back illuminated detector • unstructured entrance window results in a homogeneous responsitivity • application of an ultra-thin rectifying implant leads to a high QE in the blue and UV region • easy to apply an anti-reflective coating • entire detector volume of 450µm is radiation sensitive • high quantum efficiency in the red and NIR region • fringing effects are negligible • small detector capacitance • high signal to noise ratio • • highest electric field at readiation entrance side • narrow PSF • back illuminated detector • unstructured entrance window results in a homogeneous responsitivity • application of an ultra-thin rectifying implant leads to a high QE in the blue and UV region • easy to apply an anti-reflective coating • entire detector volume of 450µm is radiation sensitive • high quantum efficiency in the red and NIR region • fringing effects are negligible • small detector capacitance • high signal to noise ratio • • highest electric field at readiation entrance side • narrow PSF
: Measured data : Model of Si-SiOx-SiO2 : Model of pure Si-SiO2 Interface Measured and modelled reflectivity of CCD entrance window
Measurement of optical response at room temperature Optimized for CsI(Ti) scintillator readout (λ = 548nm) Standard entrance window, consisting of a thin SiO2 layer • Reflectivity of Silicon resp. Si/SiO2≈ 30% • Use layer stack of SiO2/Si3N4 as ARC • Technology allows to taylor responsitivity over • a wide wavelength range • Technological compatible ARC: • High QE in visible, maximum at 580nm • Optimum QE in NIR region • Blue and UV optimized (50% @ 300nm)
Fringing effects due to multiple light reflection between detector front and back side
Overview • • Principles of pnCCD • Optical properties • • Detector format and geometry • • Readout and data acquisition • • Measurements and Performance • Summary and outlook
51mm pnCCD with a double-sided readout,mounted onto a ceramic substrate • image area = 13.0×13.5 mm2 • chip area = 16.0×31.0 mm2 • 51 mm pixel size • 256×264 pixel plus 2×4 “light insensitive” columns • readout transfer to both sides
Brief overview • • Principles of pnCCD • Optical properties • • Detector format and geometry • • Readout and data acquisition • • Measurements and Performance • Summary and outlook
CAMEX Amplification- and Readout-Chip • Multi-correlated double-sampling filtering (MCDS) • Signal processing of all channels in parallel (132) • Serialized readout parallel to analogues signalprocessing • Selectable gains and operating modes • Electronic noise contribution less than 1 e- • Readout-speed per node up to 10MHz (i.e. 6.6µs per line on two readout nodes)
Data acquisition and real-time correction • 1000 frames / sec. • 264 lines / frame • 264 pixel / line • 70 Mpixel / sec. !!! • 140 MB/sec. Split on 4 DAQ boards • á 17.5 Mpixel / sec. • 2×14 bit flash-ADC Pipelined data processing in fast FPGA processor for real-time data correction and reduction Output of 1st CCD line is available with a latency time < 40 ms • constructing frame • MIP and cluster analysis • latency ~ 1.2 msec Example for a SH detector:
Overview Camera Controller 19’’ crate double height cPCI-Bus Power-Supplies 30 in total, free-to-ground, PC controlable, incl. monitor Fiber Interface ADC-Modul 1 ADC-Modul 2 ADC-Modul 3 ADC-Modul 4 Sequencer PS-Control 32 2 2 2 2 80 MB/s 300m Front-End-Boards (incl. clock-drivers) CAMEX pnCCD-Chip Linux PC
Sequenzer 1 … 4 ADC-Boards á 2 ADCs Spare for Voltage Controller Optical Interface Data acquisition electronic system
Overview • • Principles of pnCCD • Optical properties • • Detector format and geometry • • Readout and data acquisition • • Measurements and Performance • Summary and outlook
Spectroscopic soft X-ray performance of pnCCD • Operating Temperature = -55° C • Overall noise contribution : 2.3 e- • All events reconstructed • FWHM for singles: 45eV
Low and uniform noise performance • 66×264 pixel, ⅛ of 51mm CCD (“worst” section) • 1 of 4 output nodes on one readout side • image plus storage area • operating temperature = -55°C • “1000fps” - timing scheme • Mean noise = 2.3 electrons (rms) • 98.8% of all pixel exhibit less than 2.7 e- noise • 100% are below 3.1 e-
Increase readout speed for dedicated applications • Repetively readout of n lines with signal • merely transfer with no readout lines w/o signal • readout of next n lines • and so on … • 40×40 SH with 5×5 Pixel: • 1kHz → 1.3kHz • frame rate . . . .
Conclusion • pnCCDs exhibit a high quantum efficiency from the optical to NIR region • device with 256×264 (13.0x13.5mm2) image size and a double side readout was successfully tested for a frame rate of 1000 fps • total readout noise of 2.3e- (RMS) was achieved in this mode at an operating temperature of -55ºC • binning in transfer direction allows 2kHz, 3kHz, ... frame rates with same noise figures due to very low leakage current • low and homogeneous noise performance over entire area (no bright or hot pixel, even at higher temperatures) • optical photon counting possible down to ≈ 8 γ/pixel
← 6 cm → Back to the beginning Long term stability of pnCCD detector aboard XMM-Newton (1999): • Total area = 36cm2 • all 12 Sub-CCDs are still operating • same operating parameters (T = -90°C) • quantum efficiency unchanged • noise performance unchanged • slight radiation damage as expected: CTI FWHM after 5 years in orbit: Al-K (1.5 keV): 110 eV → 111 eV Mn-Kα (5.9 keV): 155 eV → 160 eV