D. P. Siddons

Brookhaven National Laboratory, New York, New York, United States

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Publications (192)424.83 Total impact

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    ABSTRACT: Motivated by the challenge of capturing complex hierarchical chemical detail in natural material from a wide range of applications, the Maia detector array and integrated realtime processor have been developed to acquire X-ray fluorescence images using X-ray Fluorescence Microscopy (XFM). Maia has been deployed initially at the XFM beamline at the Australian Synchrotron and more recently, demonstrating improvements in energy resolution, at the P06 beamline at Petra III in Germany. Maia captures fine detail in element images beyond 100 M pixels. It combines a large solid-angle annular energy-dispersive 384 detector array, stage encoder and flux counter inputs and dedicated FPGA-based real-time event processor with embedded spectral deconvolution. This enables high definition imaging and enhanced trace element sensitivity to capture complex trace element textures and place them in a detailed spatial context. Maia hardware and software methods provide per pixel correction for dwell, beam flux variation, dead-time and pileup, as well as off-line parallel processing for enhanced throughput. Methods have been developed for real-time display of deconvoluted SXRF element images, depth mapping of rare particles and the acquisition of 3D datasets for fluorescence tomography and XANES imaging using a spectral deconvolution method that tracks beam energy variation.
    Full-text · Article · Apr 2014 · Journal of Physics Conference Series
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    ABSTRACT: Maia is an advanced system designed specifically for scanning x-ray fluorescence microprobe applications. It consists of a large array of photodiode detectors and associated signal processing, closely coupled to an FPGA-based control and analysis system. In this paper we will describe the architecture and construction of the system.
    Full-text · Article · Apr 2014 · Journal of Physics Conference Series
  • E. H. Shaban · D. P. Siddons · D. Seifu
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    ABSTRACT: We have built and tested a 10 cm × 10 cm single Gas Electron Multiplier (GEM) X-ray detector to probe dilute amounts of Fe in a prepared sample. The detector uses Argon/Carbon Dioxide (75/25) gas mixture flowing at a slow rate through a leak proof Plexi-glass enclosure held together by O-rings and screws. The Fluorescence X-ray emitted by the element under test is directed through a Mylar window into the drift region of the detector where abundant gas is flowing. The ionized electrons are separated, drifted into the high electric field of the GEM, and multiplied by impact ionization. The amplified negatively charged electrons are collected and further amplified by a Keithley amplifier to probe the absorption edge of the element under test using X-ray absorption spectroscopy technique. The results show that the GEM detector provided good results with less noise as compared with a Silicon drift detector (SDD).
    No preview · Article · Feb 2014 · Journal of Physics Conference Series
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    ABSTRACT: A dual 32 strip sensor array is realized for use at the IXS (inelastic x-ray scattering) beamline of NSLS-II. By making use of established controls methods and sensor device recipes, our new geometry is realized quickly and at minimal cost. The detector geometry is chosen to match the output of a multi-element high-resolution energy analyzer, while the pulse thresholding is optimized for an ultra-low noise floor at a pass energy of 9.13 keV. Detector subsystems and integration are described, including sensor geometry and silicon device processing, cooling and thermal readback, bias and threshold optimizations, readout ASIC and controls, vacuum enclosure and x-ray window, mounting and positioning, and assembly procedure and testing.
    No preview · Article · Feb 2014 · Journal of Physics Conference Series

  • No preview · Article · Jan 2014
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    ABSTRACT: X-ray fluorescence images acquired using the Maia large solid-angle detector array and integrated real-time processor on the X-ray Fluorescence Microscopy (XFM) beamline at the Australian Synchrotron capture fine detail in complex natural samples with images beyond 100M pixels. Quantitative methods permit real-time display of deconvoluted element images and for the acquisition of large area XFM images and 3D datasets for fluorescence tomography and chemical state (XANES) imaging. This paper outlines the Maia system and analytical methods and describes the use of the large detector array, with a wide range of X-ray take-off angles, to provide sensitivity to the depth of features, which is used to provide an imaging depth contrast and to determine the depth of rare precious metal particles in complex geological samples.
    No preview · Article · Sep 2013 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: We investigate the interlayer (IL) thickness dependence of band offsets in a germanium based bilayer metal-oxide-semiconductor sandwich with an amorphous plasma enhanced atomic layer deposited (PE-ALD) HfO2 IL and PE-ALD grown TiO2 high k gate dielectric using hard x-ray photoelectron spectroscopy. The native Ge oxide shifts to higher oxidation state as the thickness of the IL layer was increased. The Hf 4f core line shows a broadening with increasing thickness, indicating the formation of Hf-Ge germanate. We observed a deviation from the bulk offset for films with ultra thin layers of HfO2.
    No preview · Article · Nov 2012 · Applied Physics Letters
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    ABSTRACT: "eLine", a class of multichannel time-variant integrating front-end Application Specific Integrated Circuits (ASICs), has been completed at SLAC National Accelerator Laboratory for applications at the Linac Coherent Light Source (LCLS). The class, designed for pixelated sensors with column-parallel readout, is composed of two front-end ASICs: one designed for high-dynamic range applications (eLine10k) and one designed for ultra-low noise applications (eLine100). The first allows large input full-scale signals, on the order of 104 8keV photons, with a resolution of half a photon FWHM; while the second provides low noise charge integration, up to a full-scale signal of 100 8keV photons, with an equivalent noise charge (ENC) of 55e- r.m.s. Three different prototype systems utilizing the ASICs are described. The first is a 32k-pixel X-ray Active Matrix Pixel Sensor (XAMPS) detector developed at Brookhaven National Laboratory (BNL) for the X-ray Pump Probe instrument (XPP) at LCLS. The XAMPS are monolithic detectors with fast-frame readout and large full-scale signal. In particular, they provide a full well capacity on the order of 104 8keV photons per pixel and a resolution of half a photon FWHM. The second prototype, developed around eLine10k, is a beam finder with high dynamic range. The third prototype is developed around eLine100 to be used as detector in a spectrometer. Applications, test results and performance are discussed.
    Full-text · Conference Paper · Oct 2012
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    ABSTRACT: We are developing a modular Silicon Drift Detector (SDD) X-Ray Spectrometer (XRS) for measuring the abundances of light surface elements (C to Fe) fluoresced by ambient radiation on remote airless bodies. The value of fluorescence spectrometry for surface element mapping is demonstrated by its inclusion on three recent lunar missions and by exciting new data that have recently been announced from the Messenger Mission to Mercury.The SDD-XRS instrument that we have been developing offers excellent energy resolution and an order of magnitude lower power requirement than conventional CCDs, making much higher sensitivities possible with modest spacecraft resources. In addition, it is significantly more radiation resistant than x-ray CCDs and therefore will not be subject to the degradation that befell recent lunar instruments. In fact, the intrinsic radiation resistance of the SDD makes it applicable even to the harsh environment of the Jovian system where it can be used to map the light surface elements of Europa.In this paper, we first discuss our element-mapping science-measurement goals. We then derive the necessary instrument requirements to meet these goals and discuss our current instrument development status with respect to these requirements.
    Full-text · Article · Feb 2012 · Journal of Instrumentation
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    ABSTRACT: The eLine10k is a fast-frame, 64-channel readout ASIC for SLAC Linac Coherent Light Source (LCLS) detectors. The circuit has been designed to integrate the charge from high-capacitance 2D sensors with rolling shutter and ID strip sensors. It is suitable for applications requiring large input signal range, on the order of 104 photons/pixel/pulse at 8keV (22Me-), and a resolution of half a photon FWHM (500e- r.m.s). 2D sensors with a rolling shutter like the X-ray Active Matrix Pixel Sensor (XAMPS), for which the ASIC has been optimized, present several pixels which are bussed on the same readout line. Large input capacitance to each channel is expected leading to stringent noise optimization requirements. The large required number of pixels per channel, and the fixed LCLS beam period impose limitations on the time available for the readout of each single pixel. Giving the periodic nature of the LCLS beam, the ASIC developed for this application is a time-variant system, providing low-noise charge integration, filtering and correlated double-sampling, and a processing speed up to 500k pixel/s on each channel. To cope with the large input dynamic range, a charge pump scheme has been implemented using a synchronous zero-balance measurement method. It provides on-chip 4-bit coarse digital conversion of the integrated charge. The residual charge is sampled using correlated double sampling into an analog memory, multiplexed and measured with the required resolution using an external ADC. In this paper, the ASIC architecture and performance of the final release are presented.
    Full-text · Conference Paper · Jan 2012
  • G. A. Carini · A. J. Kuczewski · D. P. Siddons
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    ABSTRACT: Tolerance of XAMPS detectors to x-ray photons was investigated at the National Synchrotron Light Source. Two experiments were carried out: first JFETs with the same characteristics of the in pixel transistor were irradiated; then the radiation hardness of a 64×64-pixel detector was investigated. An increase of leakage current was observed and significantly reduced after a very low temperature forming gas annealing. These results confirm that this detector is suitable for application at IV generation light sources.
    No preview · Article · Oct 2011
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    ABSTRACT: A hard x-ray micro-nanoprobe has commenced operation at the Australian Synchrotron providing versatile x-ray fluorescence microscopy across an incident energy range from 4 to 25 keV. Two x-ray probes are used to collect mu-XRF and mu-XANES for elemental and chemical microanalysis: a Kirkpatrick-Baez mirror microprobe for micron resolution studies and a Fresnel zone plate nanoprobe capable of 60-nm resolution. Some unique aspects of the beamline design and operation are discussed. An advanced energy dispersive x-ray fluorescence detection scheme named Maia has been developed for the beamline, which enables ultrafast x-ray fluorescence microscopy.
    Full-text · Article · Sep 2011
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    ABSTRACT: We have developed a new thin-window, n-type, low-resistivity, spiral silicon drift detector (SDD) array - to be used as an extraterrestrial X-ray spectrometer (in varying environments) for NASA. To achieve low-energy response, a thin SDD entrance window was produced using a previously developed method. These thin-window devices were also produced on lower resistivity, thinner, n-type, silicon material, effectively ensuring their radiation hardness in anticipation of operation in potentially harsh radiation environments (such as found around the Jupiter system). Using the Indiana University Cyclotron Facility beam line RERS1, we irradiated a set of suitable diodes up to 5 Mrad and the latest iteration of our ASICs up to 12 Mrad. Then we irradiated two hybrid detectors consisting of newly, such-produced in-house (BNL) SDD chips bonded with ASICs with doses of 0.25 Mrad and 1 Mrad. Also we irradiated another hybrid detector consisting of previously produced (by KETEK) on n-type, high-resistivity SDD chip bonded with BNL's ASICs with a dose of 1 Mrad. The measurement results of radiated diodes (up to 5 Mrad), ASICs (up to 12 Mrad) and hybrid detectors (up to 1 Mrad) are presented here.
    No preview · Article · Jan 2011
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    ABSTRACT: Hard x-ray photoelectron spectroscopy has been used to study the band alignment between atomic layer deposited HfO{sub 2} on clean Ge (100) and nitrogen treated Ge (100) surfaces. The position of the valence-band maximum was determined by convolving theoretically calculated density of states from first-principles calculations and comparing with experimental valence-band data. Using Kraut's method, the valence-band offsets were found to be 3.2 {+-} 0.1 and 3.3 {+-} 0.1 eV for the samples grown on clean and N passivated Ge, respectively. The oxide charge measured from capacitance-voltage measurements shows a significant increase between the two samples; however, the small change in the band offset between the two systems strongly indicates negligible contribution of the interface to the conduction/valence-band barrier and the band alignment of the heterojunctions.
    Full-text · Article · Dec 2010 · Applied Physics Letters
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    ABSTRACT: We report on the design of the VIPIC IC (Vertically Integrated Pixel Imaging Chip) designed for X-ray Photon Correlation Spectroscopy (XPCS) experiments by FNAL in collaboration with AGH-UST. The VIPIC chip is a prototype matrix with 64 × 64 pixels with 80 μm × 80 μm pixel size and consists of two layers: analog and digital. The single analog pixel cell consists of a charge sensitive amplifier, a shaper, a single current discriminator and trim DACs. The simulated gain is 52 μV/e<sup>-</sup>, the noise ENC <; 150 e<sup>-</sup> rms (with C<sub>det</sub>= 100 fF) and the peaking time t<sub>p</sub> <; 250 ns. The power consumption is 25 μW/pixel in the analog part. The digital layer of the VIPIC integrated circuit is divided into 16 readout groups of pixels read out in parallel via separate serial ports with nominal frequency of the 100 MHz clock using the LVDS standard. The readout within each group is zero-suppressed. The sparsification scheme (addresses of hit pixels only) allows a dead-time free readout.
    No preview · Conference Paper · Dec 2010
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    ABSTRACT: Micro-fabricated bi-prisms have been used to create an interference pattern from an incident hard X-ray beam, and the intensity of the pattern probed with fluorescence from a 30 nm-thick metal film. Maximum fringe visibility exceeded 0.9 owing to the nano-sized probe and the choice of single-crystal prism material. A full near-field analysis is necessary to describe the fringe field intensities, and the transverse coherence lengths were extracted at APS beamline 8-ID-I. It is also shown that the maximum number of fringes is dependent only on the complex refractive index of the prism material.
    No preview · Article · Jul 2010 · Journal of Synchrotron Radiation

  • No preview · Article · Jul 2010 · Injury
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    ABSTRACT: The Maia detector system is engineered for energy dispersive x-ray fluorescence spectroscopy and elemental imaging at photon rates exceeding 10{sup 7}/s, integrated scanning of samples for pixel transit times as small as 50 {micro}s and high definition images of 10{sup 8} pixels and real-time processing of detected events for spectral deconvolution and online display of pure elemental images. The system developed by CSIRO and BNL combines a planar silicon 384 detector array, application-specific integrated circuits for pulse shaping and peak detection and sampling and optical data transmission to an FPGA-based pipelined, parallel processor. This paper describes the system and the underpinning engineering solutions.
    No preview · Article · Jun 2010
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    ABSTRACT: Application of nuclear microprobe event-by-event data acquisition approaches to synchrotron elemental imaging is at the heart of the design of a large energy-dispersive detector array called Maia, under development by CSIRO and BNL for SXRF elemental imaging on the X-ray microprobe. A new project is aimed at harnessing this development to provide high throughput PIXE imaging on the CSIRO Nuclear Microprobe. Maia combines a 1.2sr solid-angle 384 detector array, integrated scanning and real-time processing including spectral deconvolution of full-spectral data. Results using a Maia prototype demonstrate the potential using SXRF application data with elemental images of up 100M pixels.
    Full-text · Article · Jun 2010 · Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms
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    ABSTRACT: Synchrotron X-ray fluorescence (SXRF) and X-ray absorption spectroscopy (XAS) have become standard tools to measure element concentration, distribution at micrometer- to nanometer-scale, and speciation (e.g., nature of host phase; oxidation state) in inhomogeneous geomaterials. The new Maia X-ray detector system provides a quantum leap for the method in terms of data acquisition rate. It is now possible to rapidly collect fully quantitative maps of the distribution of major and trace elements at micrometer spatial resolution over areas as large as 1 × 5 cm2. Fast data acquisition rates also open the way to X-ray absorption near-edge structure (XANES) imaging, in which spectroscopic information is available at each pixel in the map. These capabilities are critical for studying inhomogeneous Earth materials. Using a 96-element prototype Maia detector, we imaged thin sections of an oxidized pisolitic regolith (2 × 4.5 mm2 at 2.5 × 2.5 μm2 pixel size) and a metamorphosed, sedimentary exhalative Mn-Fe ore (3.3 × 4 mm2 at 1.25 × 5 μm2). In both cases, As K-edge XANES imaging reveals localized occurrence of reduced As in parts of these oxidized samples, which would have been difficult to recognize using traditional approaches.
    Full-text · Article · May 2010 · American Mineralogist

Publication Stats

4k Citations
424.83 Total Impact Points


  • 1986-2014
    • Brookhaven National Laboratory
      • • Physics Department
      • • Instrumentation Division
      • • Accelerator Test Facility
      • • Nonproliferation and National Security Department
      New York, New York, United States
    • The University of Manchester
      Manchester, England, United Kingdom
  • 2009
    • University of Melbourne
      • School of Physics
      Melbourne, Victoria, Australia
  • 2004
    • Universidade Federal do Paraná
      Curityba, Paraná, Brazil
  • 2000
    • The University of Warwick
      • School of Engineering
      Warwick, ENG, United Kingdom
  • 1994
    • Politecnico di Milano
      • Department of Electronics, Information, and Bioengineering
      Milano, Lombardy, Italy
  • 1990
    • Institut Laue-Langevin
      Grenoble, Rhône-Alpes, France
  • 1985
    • Keele University
      Newcastle-under-Lyme, England, United Kingdom
  • 1983
    • University College London
      Londinium, England, United Kingdom
  • 1982-1983
    • King's College London
      Londinium, England, United Kingdom
  • 1980
    • Université Paris-Sud 11
      Orsay, Île-de-France, France