24 research outputs found
The Adaptive Gain Integrating Pixel Detector at the European XFEL
The Adaptive Gain Integrating Pixel Detector (AGIPD) is an x-ray imager,
custom designed for the European x-ray Free-Electron Laser (XFEL). It is a
fast, low noise integrating detector, with an adaptive gain amplifier per
pixel. This has an equivalent noise of less than 1 keV when detecting single
photons and, when switched into another gain state, a dynamic range of more
than 10 photons of 12 keV. In burst mode the system is able to store 352
images while running at up to 6.5 MHz, which is compatible with the 4.5 MHz
frame rate at the European XFEL. The AGIPD system was installed and
commissioned in August 2017, and successfully used for the first experiments at
the Single Particles, Clusters and Biomolecules (SPB) experimental station at
the European XFEL since September 2017. This paper describes the principal
components and performance parameters of the system.Comment: revised version after peer revie
Detector developments for photon science at DESY
The past, current and planned future developments of X-ray imagers in the Photon-Science Detector Group at DESY-Hamburg is presented. the X-ray imagers are custom developed and tailored to the different X-ray sources in Hamburg, including the storage ring PETRA III/IV; the VUV-soft X-ray free electron laser FLASH, and the European Free-Electron Laser. Each source puts different requirements on the X-ray detectors, which is described in detail, together with the technical solutions implemented
Megapixels @ Megahertz -- The AGIPD High-Speed Cameras for the European XFEL
The European XFEL is an extremely brilliant Free Electron Laser Source with a
very demanding pulse structure: trains of 2700 X-Ray pulses are repeated at 10
Hz. The pulses inside the train are spaced by 220 ns and each one contains up
to photons of 12.4 keV, while being fs in length. AGIPD,
the Adaptive Gain Integrating Pixel Detector, is a hybrid pixel detector
developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with
these properties. It is a fast, low noise integrating detector, with single
photon sensitivity (for keV) and a large dynamic
range, up to photons at 12.4 keV. This is achieved with a charge
sensitive amplifier with 3 adaptively selected gains per pixel. 352 images can
be recorded at up to 6.5 MHz and stored in the in-pixel analogue memory and
read out between pulse trains. The core component of this detector is the AGIPD
ASIC, which consists of pixels of . Control of the ASIC's image acquisition and analogue readout is
via a command based interface. FPGA based electronic boards, controlling ASIC
operation, image digitisation and 10 GE data transmission interface AGIPD
detectors to DAQ and control systems. An AGIPD 1 Mpixel detector has been
installed at the SPB experimental station in August 2017, while a second one is
currently commissioned for the MID endstation. A larger (4 Mpixel) AGIPD
detector and one to employ Hi-Z sensor material to efficiently register photons
up to keV are currently under construction.Comment: submitted to the proceedings of the ULITIMA 2018 conference, to be
published in NIM
Ultra-fast yttrium hydride chemistry at high pressures via non-equilibrium states induced by x-ray free electron laser
Controlling the formation and stoichiometric content of desired phases of
materials has become a central interest for the study of a variety of fields,
notably high temperature superconductivity under extreme pressures. The further
possibility of accessing metastable states by initiating reactions by x-ray
triggered mechanisms over ultra-short timescales is enabled with the
development of x-ray free electron lasers (XFEL). Utilizing the exceptionally
high brilliance x-ray pulses from the EuXFEL, we report the synthesis of a
previously unobserved yttrium hydride under high pressure, along with
non-stoichiometric changes in hydrogen content as probed at a repetition rate
of 4.5\,MHz using time-resolved x-ray diffraction. Exploiting non-equilibrium
pathways we synthesize and characterize a hydride with yttrium cations in an
\textit{A}15 structure type at 125\,GPa, predicted using crystal structure
searches, with a hydrogen content between 4.0--5.75 hydrogens per cation, that
is enthalpically metastable on the convex hull. We demonstrate a tailored
approach to changing hydrogen content using changes in x-ray fluence that is
not accessible using conventional synthesis methods, and reveals a new paradigm
in metastable chemical physics
Segmented flow generator for serial crystallography at the European X-ray free electron laser
Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported
Diffraction anomalous fine structure in Laue geometry
This thesis deals with the further development of the method of Borrmannspectroscopy and the development of the novel method of diffractionanomalous fine structure in Laue geometry.Borrmann spectroscopy utilizes the Borrmann effect in order to enhancethe quadrupol absorption, which enables studying weak quadrupoltransitions. In the present work a model is developed, which describes thedependence of the quadrupol enhancement on temperature and anisotropyof the chemical environment. This model is used to describe the Borrmannspectroscopy results obtained from a strontium titanate single crystal.Furthermore, the influence of the mosaicity of real crystals on thequadrupole enhancement is studied by means of simulations, which arebased on the dynamical theory of diffraction and a modified structuremodel of barium titanate.The method of diffraction anomalous fine structure (DAFS) is based onthe combination of X-ray diffraction and absorption spectroscopy and allowsinvestigating the local atomic structure of centrosymmetric crystalsutilising the additional selectivity due to diffraction. In the present workthe novel method of diffraction anomalous fine struture in Laue geometry(LDAFS) is developed. It utilizes the intensity of the Laue geometrydiffracted beam, which experiences an altered absorption due to the Borrmanneffect. Its experimental applicability is verified by experiments ona barium titanate single crystal and comparison with conventional X-rayabsorption spectroscopy results
Development of CoRDIA: a High-Speed Imaging Detector, for Diffraction-Limited Synchrotron Rings and Continuous-Wave Free Electron Lasers
Development of CoRDIA: an Imaging Detector for next-generation Photon Science X-ray Sources
The Continuous Readout Digitising Imager Array (CoRDIA) is an X-ray imager being developed, capable of continuous operation in excess of 100 kframe/s. An overview of the architecture is presented, as well as the first test results
Development of CoRDIA: an Imaging Detector for next-generation Synchrotron Rings and Free Electron Lasers
An X-ray imager is being developed for use in diffraction-limited Synchrotron Rings and Continuous Wave Free Electron Lasers. The imager is named CoRDIA (COntinuous Readout Digitising Imager Array) and aims at achieving continuous operation at a frame rate in excess of 100kHz. Other goals include single-photon sensitivity at 12 keV (or below), a full well in excess of 10k photon/pixel/image, and a 100μm pixel pitch. The detector ASIC will be compatible with multiple sensor materials to cover different energy ranges. Exploratory prototypes of the readout ASIC (basic circuital blocks) have been manufactured in in TSMC 65nm technology: they are presenltly under test
Single and multi-pulse based X-ray Photon Correlation Spectroscopy
The ability of pulsed nature of synchrotron radiation opens up the possibility of studying microsecond dynamics in complex materials via speckle-based techniques. Here, we present the study of measuring the dynamics of a colloidal system by combining single and multiple X-ray pulses of a storage ring. In addition, we apply speckle correlation techniques at various pulse patterns to collect correlation functions from nanoseconds to milliseconds. The obtained sample dynamics from all correlation techniques at different pulse patterns are in very good agreement with the expected dynamics of Brownian motions of silica nanoparticles in water. Our study will pave the way for future pulsed X-ray investigations at various synchrotron X-ray sources using individual X-ray pulse patterns