| 1. |
- Allahgholi, A., et al.
(författare)
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AGIPD 1.0 : The high-speed high dynamic range readout ASIC for the adaptive gain integrating pixel detector at the European XFEL
- 2014
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Ingår i: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479960972
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Konferensbidrag (refereegranskat)abstract
- AGIPD is a hybrid pixel X-ray detector developed by a collaboration between Deutsches Elektronen-Synchrotron (DESY), Paul-Scherrer-Institute (PSI), University of Hamburg and the University of Bonn. The detector is designed to comply with the requirements of the European XFEL. The radiation tolerant Application Specific Integrated Circuit (ASIC) is designed with the following highlights: high dynamic range, spanning from single photon sensitivity up to 104 × 12.4 keV photons, achieved by the use of dynamic gain switching, auto-selecting one of 3 gains of the charge sensitive pre-amplifier. To cope with the unique features of the European XFEL source, image data is stored in 352 analogue memory cells per pixel. The selected gain is stored in the same way and depth, encoded as one of 3 voltage levels. These memories are operated in random-access mode at 4.5MHz frame rate. Data is read out on a row-by-row basis via multiplexers to the DAQ system for digitisation during the 99.4ms gap between the bunch trains of the European XFEL. The AGIPD 1.0 ASIC features 64×64 pixels with a pixel area of 200×200 μm2. It is bump-bonded to a 500 μm thick silicon sensor. The principles of the chip architecture were proven in different experiments and the ASIC characterization was performed with a series of development prototypes. The mechanical concept of the detector system was developed in close contact with the XFEL beamline scientists to ensure a seamless integration into the beamline setup and is currently being manufactured. The first single module system was successfully tested at APS1 the high dynamic range allows imaging of the direct synchrotron beam along with single photon sensitivity and burst imaging of 352 subsequent frames synchronized to the source.
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| 2. |
- Allahgholi, A., et al.
(författare)
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AGIPD, the electronics for a high speed X-ray imager at the Eu-XFEL
- 2014
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Ingår i: Proceedings of Science. - : Proceedings of Science (PoS).
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Konferensbidrag (refereegranskat)abstract
- The AGIPD (Adaptive Gain Integrated Pixel Detector) X-ray imaging camera will be operated at the X-ray Free Electron Laser, Eu-XFEL, under construction in Hamburg, Germany. Key parameters are 1 million 200 μm square pixels, single 12.4 keV photon detection and a dynamic range to 10 000/pixel/image. The developed sensors, ASICs, PCB-electronics and FPGA firmware acquire individual images per bunch at 27 000 bunches/s, packed into 10 bunch-trains/s with a bunch separation of 222 ns. Bunch-trains are handled by 352 analogue storage cells within each pixel of the ASIC and written during the 0.6msec train delivery. Therefore AGIPD can store 3520 images/s from the delivered 27 000 bunches/s. Random addressing provides reusability of each cell after an image has been declared as low-quality, so that good images can be selected. Digitization is performed between trains (99.4 msec). In the paper all functional blocks are introduced. The details concentrate on the DAQ-chain PCB-electronics and the slow control. A dense area of 1024 ADC-channels, each with a pickup-noise filtering and sampling of up to 50 MS/s/ADC and a serial output of 700 Mbit/s/ADC. FPGAs operate the ASICs synchronized to the bunch structure and collect the bit streams from 64 ADCs/FPGA. Pre-sorted data is transmitted on 10 GbE links out of the camera head using the time between trains. The control and monitoring of the camera with 600 A current consumption is based on a micro-controller and I2C bus with an addressing architecture allowing many devices and identical modules. The high currents require planned return paths at the system level. First experimental experience with the constructed components will be presented.
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| 3. |
- Allahgholi, A., et al.
(författare)
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The AGIPD 1.0 ASIC : Random access high frame rate, high dynamic range X-ray camera readout for the European XFEL
- 2015
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Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
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Konferensbidrag (refereegranskat)abstract
- 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 1012 photons of 12.4 keV, while being ≤ 100 fs in length. AGIPD (Adaptive Gain Integrating Pixel Detector) is a hybrid 1M-pixel detector developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with these properties. Thus the readout ASIC has to provide not only single photon sensitivity and a dynamic range ≳ 104 photons/pixel in the same image but also a memory for as many images of a pulse train as possible for delayed readout prior to the next train. The AGIPD 1.0 ASIC uses a 130 nm CMOS technology and radiation tolerant techniques to withstand the radiation damage incurred by the high impinging photon flux. Each ASIC contains 64 × 64 pixels of 200μmχ200μm. The circuit of each pixel contains a charge sensitive preamplifier with threefold switchable gain, a discriminator for an adaptive gain selection, and a correlated double sampling (CDS) stage to remove reset and low-frequency noise components. The output of the CDS, as well as the dynamically selected gain is sampled in a capacitor-based analogue memory for 352 samples, which occupies about 80% of a pixels area. For readout each pixel features a charge sensitive buffer. A control circuit with a command based interface provides random access to the memory and controls the row-wise readout of the data via multiplexers to four differential analogue ports. The AGIPD 1.0 full scale ASIC has been received back from the foundry in fall of 2013. Since then it has been extensively characterised also with a sensor as a single chip and in 2 × 8-chip modules for the AGIPD 1 Mpix detector. We present the design of the AGIPD 1.0 ASIC along with supporting results, also from beam tests at PETRA III and APS, and show changes incorporated in the recently taped out AGIPD 1.1 ASIC upgrade.
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| 4. |
- Becker, J., et al.
(författare)
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Architecture and design of the AGIPD detector for the European XFEL
- 2012
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Konferensbidrag (refereegranskat)abstract
- AGIPD is a hybrid pixel detector developed by DESY, PSI, the University of Bonn and the University of Hamburg. The detector is targeted for use at the European XFEL, a source with unique properties: a bunch train of 2700 pulses with > 1012 photons of 12 keV each, only 100 fs long and with a 220 ns spacing, is repeated at a 10Hz rate. This puts up very demanding requirements: dynamic range has to cover the detection of single photons and extend up to > 104 photons/pixel in the same image, and as many images, as possible have to be recorded in the pixel to be read out between pulse trains. The high photon flux impinging on the detector also calls for a very radiation hard design of sensor and ASIC. The detector will consist of 16 Sensor modules arranged around a central hole for the direct beam. Each made of a single sensor bump-bonded to 2 × 8 readout chips of 64 × 64 pixels in a grid of 200 μm pitch. Each pixel of these ASICs contains a charge sensitive preamplifier featuring adaptive gain switching, changing sensitivity in three ranges, and a buffer to provide correlated double sampling (in the highest sensitivity mode). Most of the pixel area, albeit, is used for an analogue memory to record 352 frames. It is operated in random-access mode: data containing bad frames can be overwritten and the memory can be used in the most efficient way. The readout between two bunch trains is arranged via 4 ports: Data from pixels of one row is read in parallel and serialised by 4 multiplexers at the end of the pixel columns and driven off-chip as differential signals. The operation of the ASIC is controlled via a three-line serial interface, using a command based protocol. It is also used to configure the chip's operational parameters and internal timings. © 2012 IEEE.
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| 5. |
- Becker, J., et al.
(författare)
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High speed cameras for X-rays : AGIPD and others
- 2013
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Ingår i: Journal of Instrumentation. - 1748-0221 .- 1748-0221. ; 8:1, s. Art. no. C01042-
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Tidskriftsartikel (refereegranskat)abstract
- Experiments at high pulse rate Free Electron Laser (FEL) facilities require new cameras capable of acquiring 2D images at high rates, handling large signal dynamic ranges and resolving images from individual pulses. The Adaptive Gain Integrated Pixel Detector (AGIPD) will operated with pulse rates and separations of 27000/s and 220 ns, respectively at European XFEL. Si-sensors, ASICs, PCBs, and FPGA logic are developed for a 1 Mega-pixel camera with 200 μm square pixels with per-pulse occupancies 104. Data from 3520 images/s will be transferred with 80 Gbits/s to a DAQ-system. The electronics have been adapted for use in other synchrotron light source detectors.
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| 6. |
- Becker, J., et al.
(författare)
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The high speed, high dynamic range camera AGIPD
- 2013
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Ingår i: IEEE Nuclear Science Symposium Conference Record. - : IEEE conference proceedings. - 9781479905348 ; , s. Art. no. 6829504-
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Konferensbidrag (refereegranskat)abstract
- The European X-Ray Free Electron Laser (XFEL) will provide ultra short, highly coherent X-ray pulses which will revolutionize scientific experiments in a variety of disciplines spanning physics, chemistry, materials science, and biology. One of the differences between the European XFEL and other free electron laser sources is the high pulse frequency of 4.5 MHz. The European XFEL will provide pulse trains, consisting of up to 2700 pulses separated by 220 ns (600 μs in total) followed by an idle time of 99.4 ms, resulting in a supercycle of 10 Hz. Dedicated fast 2D detectors are being developed, one of which is the Adaptive Gain Integrating Pixel Detector (AGIPD). AGIPD is based on the hybrid pixel technology. The design goals of the recently produced, radiation hard Application Specific Integrated Circuit (ASIC) with dynamic gain switching amplifiers are (for each pixel) a dynamic range of more than 10 4 12.4 keV photons in the lowest gain, single photon sensitivity in the highest gain, an analog memory capable of storing 352 images, and operation at 4.5 MHz frame rate. A vetoing scheme allows to maximize the number of useful images that are acquired by providing the possibility to overwrite any previously recorded image during the pulse train. The AGIPD will feature a pixel size of (200 μm)2 and a silicon sensor with a thickness of 500 μm. The image data is read out and digitized between pulse trains. © 2013 IEEE.
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| 7. |
- Greiffenberg, D., et al.
(författare)
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Optimization of the noise performance of the AGIPD prototype chips
- 2013
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Ingår i: Journal of Instrumentation. - 1748-0221 .- 1748-0221. ; 8:10, s. Art. no. P10022-
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Tidskriftsartikel (refereegranskat)abstract
- The charge integrating readout electronics AGIPD (adaptive gain integrating pixel detector) is a hybrid detector system developed for the European XFEL. It features a threefold dynamic gain switching to be able to resolve single photons and to cover a dynamic range of 104·12.4 keV photons. As a result of dynamic gain switching, single photon resolution will be achieved in the high gain stage, while the maximum dynamic range will be reached in the low gain stage. The specification to resolve single photons requires a signal-over-noise ratio of at least 10 for a single incoming photon with an energy of 12.4 keV. When using a silicon sensor, that translates to an equivalent noise charge of less than 343 e-. Several AGIPD prototype chips have been designed and characterized, particularly focusing on the noise performance. During the testing phase, the dominant noise sources were identified and the corresponding circuit blocks were improved in the subsequent ASICs. This paper reports on the procedures to identify the dominating noise sources, the optimization process of the circuit blocks and discusses the effect of the optimization on the noise performance.© 2013 IOP Publishing Ltd and Sissa Medialab srl.
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| 8. |
- Greiffenberg, D., et al.
(författare)
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Towards AGIPD1.0 : Optimization of the dynamic range and investigation of a pixel input protection
- 2014
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Ingår i: Journal of Instrumentation. - 1748-0221 .- 1748-0221. ; 9:6, s. Art. no. P06001-
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Tidskriftsartikel (refereegranskat)abstract
- AGIPD is a charge integrating, hybrid pixel readout ASIC, which is under development for the European XFEL [1,2]. A dynamic gain switching logic at the output of the preamplifier (preamp) is used to provide single photon resolution as well as covering a dynamic range of at least 104·12.4 keV photons [3,4]. Moreover, at each point of the dynamic range the electronics noise should be lower than the Poisson fluctuations, which is especially challenging at the points of gain switching. This paper reports on the progress of the chip design on the way to the first full-scale chip AGIPD1.0, focusing on the optimization of the dynamic range and the implementation of protection circuits at the preamplifier input to avoid pixel destruction due to high intense spots. © 2014 IOP Publishing Ltd and Sissa Medialab srl.
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| 9. |
- Kruger, R., et al.
(författare)
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Orbital ordering in LaMnO3 investigated by resonance Raman spectroscopy
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 92
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Tidskriftsartikel (refereegranskat)abstract
- Orbital ordering leads to an unconventional excitation spectrum that we investigate by resonance Raman scattering using incident photon energies between 1.7 and 5.0 eV. We use spectral ellipsometry to determine the corresponding dielectric function. Our results show resonant behavior of the phonon Raman cross section when the laser frequency is close to the orbiton-excitation energy of 2 eV in LaMnO3. We show an excellent agreement between theoretical calculations based on the Franck-Condon mechanism activating multiphonon Raman scattering in first order of the electron-phonon coupling and the experimental data of phonons with different symmetries.
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