Development and characterisation of the radiation tolerant HELIX 128-2 readout chip for the HERA-B microstrip detectors

In der vorliegenden Doktorarbeit wurden große Teile der Schaltung des Verstärker- und Auslesechips HELIX128-2 entwickelt. Dazu gehörten unter anderem der 'Bias Generator', eine Schaltung zur Einstellung der Ruheströme und Kontrollspannungen der Verstärkerstufen mit Digital-zu-Analog Wandlern, sowie eine serielle Schnittstelle zum Programmieren der Betriebsparameter des Chips. Des weiteren wurde eine vollständige Charakterisierung des Chips, einschließlich der Bestrahlung mit einer 137Cs-Quelle durchgeführt. Die bei den dazu notwendigen Tests und Messungen gefundenen Unzulänglichkeiten führten zu einer Weiterentwicklung des Chips in verschiedenen Revisionsstufen: 2.2, 2.3, 3.0, 3.1 und 3.1a. Die dabei eingeflossenen Modifikationen betrafen mit Ausnahme von Eingangsstufe und Multiplexer alle Schaltungsteile. Insbesondere an der Pipeline Schreib-/Lesesteuerung wurden im Rahmen dieser Arbeit Verbesserungen vorgenommen. HELIX128-2 ist eine rauscharme (ENC = 462e+35.4e/pF für einen neuen Chip, ENC = 571e+52.0e/pF nach 3.9kGy) VLSI-Schaltung zur Auslese von 128 Kanälen eines Silizium-Streifenzählers oder einer MSGC. Die Architektur implementiert neben einem analogen Auslesepfad, der dem Konzept des CERN RD20/FElix Chip folgt (Ladungsverstärker, Pulsformer, analoger Zwischenspeicher und serielle Auslese der Kanäle getriggerter Daten) auch über einen unverzögerten binären Datenpfad. Er ist für Triggeranwendungen gedacht und über der Eingangsstufe folgende Komparatoren realisiert, deren Signale in Gruppen von vier Kanälen zusammengefaßt werden. Die vorliegende Arbeit gliedert sich daher in zwei Teile: Der erste Teil ist die Beschreibung des HELIX128-2 mit besonderem Schwerpunkt auf der Schaltungsimplementation. Der zweite Teil gibt die Ergebnisse der Charakterisierung des Chips wieder und beinhaltet die Chipeigenschaften unter Bestrahlung bis 3.9kGy

n-XYTER: A CMOS read-out ASIC for a new generation of high rate multichannel counting mode neutron detectors

For a new generation of 2-D neutron detectors developed in the framework of the EU NMI3 project DETNI [1], the 128-channel frontend chip n-XYTER has been designed. To facilitate the reconstruction of single neutron incidence points, the chip has to provide a spatial coordinate (represented by the channel number), as well as time stamp and amplitude information to match the data of x- and y-coordinates. While the random nature of the input signals calls for self-triggered operation of the chip, on-chip derandomisation and sparsi cation is required to exploit the enormous rate capability of these detectors ( 4 106cm2s1). The chosen architecture implements a preampli er driving two shapers with di erent time constants per channel. The faster shaper drives a single-pulse discriminator with subsequent time-walk compensation. The output of this circuit is used to latch a 14-bit time stamp with a 2 ns resolution and to enable a peak detector circuit fed by the slower shaper branch. The analogue output of the peak detector as well as the time stamp are stored in a 4-stage FIFO for derandomisation. The readout of these FIFOs is accomplished by a token-ring based multiplexer working at 32 MHz, which accounts for further derandomisation, sparsi cation and dynamic bandwidth distribution. The chip was submitted for manufacturing in AMS's C35B4M3 0.35µm CMOS technology in June 2006

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$^4$ 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

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 $10^{12}$ photons of 12.4 keV, while being $\le 100$ 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 $\text{E}_{\gamma} \ge 6$ keV) and a large dynamic range, up to $10^4$ 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 $64 \times 64$ pixels of $200 {\mu}\text{m} \times 200 {\mu}\text{m}$. 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 $\text{E}_{\gamma} \approx 25$ keV are currently under construction.Comment: submitted to the proceedings of the ULITIMA 2018 conference, to be published in NIM

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

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

Beiträge zum 28. Darmstädter Geotechnik-Kolloquium am 09. März 2022

Themenschwerpunkte: 1. Modell- und Feldversuche 2. Digitalisierung und künstliche Intelligenz in der Geotechnik 3. Nationale und internationale Großprojekte 4. Normung und Rechtliche

Beiträge zum 28. Darmstädter Geotechnik-Kolloquium am 09. März 2022

Themenschwerpunkte: 1. Modell- und Feldversuche 2. Digitalisierung und künstliche Intelligenz in der Geotechnik 3. Nationale und internationale Großprojekte 4. Normung und Rechtliche

Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

A new mechanism for the generation of a self-exited oscillation of combustion in a generic combustion chamber typical for aero-engine combustors is described. The cause of the oscillation is the phase change from liquid to vapour which happens when the preheat temperature of the air flowing through the burner exceeds the boiling temperature at the operating pressure and the fuel flow is so low that heat transfer to the liquid fuel causes evaporation within the fuel channels of the burner. Liquid fuel and vapour alternatively enter the airstream of the burner. This leads to an instable situation for the flame. Measurements of chemiluminescence and liquid fuel show nearly complete extinction and reignition for the limit cycle. Prevention of the oscillation is possible by better thermal management on the fuel path

Association between tumor response and postoperative morbidity after neoadjuvant chemotherapy for gastroesophageal adenocarcinoma?

Aim: The recommended treatment for locally advanced gastroesophageal adenocarcinoma has changed to a multimodal approach including neoadjuvant chemotherapy. The aim of this study was to assess potential associations between response to neoadjuvant therapy and post-operative morbidity in patients with gastroesophageal adenocarcinoma.Methods: Sixty-one patients undergoing surgical resection of gastroesophageal adenocarcinoma following neoadjuvant chemotherapy were analyzed. Patients were dichotomized into histopathological responders (Becker grade Ia-II, n = 37) and nonresponders (Becker grade III, n = 24). Perioperative complications were assessed according to the Clavien-Dindo classification. An association between response to neoadjuvant chemotherapy and surgical complications was evaluated with the chi-square or Fisher test where appropriate.Results: Twenty over thirty-seven responders (54.1%) and 17/24 non-responders (70.8%) had perioperative complications of any grade (P = 0.19). The most frequent complications were anastomotic leakage, which had a higher incidence among non-responders (4/24; 16.7%) than responders (1/37; 2.7%; Fisher's test: P = 0.07); and pulmonary complications, which showed no difference in incidence between non-responders (11/24; 45.8%) and responders (13/37; 35.1%; P = 0.57).Conclusion: In patients undergoing resection of gastroesophageal adenocarcinoma after neoadjuvant chemotherapy, there was no association between response and incidence of perioperative complications. However, there was a borderline significant higher incidence of anastomotic leakage among non-responders