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Linear accelerators, like the Free-electron LASer in Hamburg (FLASH) or the European X-Ray Free Electron Laser (E-XFEL) take advantage of the digital Low Level Radio Frequency (LLRF) system to control the phase and amplitude of an electromagnetic field inside superconducting cavities. The real-time control LLRF system, processing data within a few microseconds, has to fulfil performance requirements and provide comprehensive monitoring and diagnostics. The AMC-based controller (DAMC-TCK7) board was developed as a general purpose high-performance low-latency data processing unit designed according to the PICMG MTCA.4 spec. The module provides the processing power, data memory, communication links, reference clock, trigger and interlock signals that are required in modern LLRF control systems. The module was originally designed as a cavity field stabilizing controller for standing-wave linear accelerators. However, the application of the board is much wider because it is a general purpose data processing module suitable for systems requiring low latency and high-speed digital signal processing. According to authors’ knowledge this is the first MTCA.4 module offering 12.5 Gbps links, unified Zone 3 connectivity and advanced Module Management Controller proposed by DESY. The DAMC-TCK7 card was used as a hardware template for the development of the other AMC modules of the XFEL accelerator’s LLRF system. This paper discusses the requirements for the digital real-time data processing module, presents the laboratory performance evaluation and verification in Cryo-Module Test Bench (CMTB) at DESY. [ABSTRACT FROM PUBLISHER]

The performances of the OFFSET3 tracker (Optical Fiber Folded Scintillating Extended Tracker) are presented. It exploits a novel system for particle tracking, designed to achieve real-time particle imaging and tracking, large detection areas, and a high spatial resolution especially suitable for applications in medical diagnostics. The tracker is composed by two 288 \times 288~\mm^2 FOV position detectors stacked by 10 cm, made by 500 micron square scintillating fiber ribbons for both directions. The track position information is extracted in real-time in an innovative way, using a reduced number of readout channels, by means of which it is possible to obtain the large detection area with moderate cost and complexity. The architecture has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The performances of the tracker were investigated by beta sources, cosmic rays, 60 MeV-250 MeV proton and 400 MeV/A carbon clinical beams. [ABSTRACT FROM PUBLISHER]

In modern particle accelerators, radio frequency (RF) phase detectors have to fulfill high demands on stability and accuracy to meet the goals of state-of-the-art synchronization systems. Especially challenging are those cases where the RF signal phase shift accuracy must be measured with fs accuracy for several hours over the full 2 \pi phase detection range. In these cases special measures on the component’s nonlinearities and RF channel isolation have to be taken. The long-term stability of the phase detector is mostly affected by temperature and humidity variations. To meet the synchronization goals, we have built a phase detector that incorporates a high-speed dual analog-to-digital converter (ADC) with a special circuit for continuous phase drift calibration. In the calibration circuit we successfully combined the RF signal with an RF calibration signal (second tone) to compensate common phase drift that occurs in the microstrip lines, the RF transformers, and the ADC. The second-tone RF signals are directly converted to the digital domain by the fast ADC and, based on signal processing in the field-programmable gate array, are used to calculate the RF signal phase shift correction caused by detector drifts. In this paper, potential error sources of the analog and the digital part of the so-called two-tone calibration technique that limit the phase detector precision are discussed. Finally, the experimental results are presented showing a long-term phase measurement stability better than 0.01\ ^\circ \ pk-\ pk evaluated at an RF frequency of 1.3 GHz over a few days. [ABSTRACT FROM PUBLISHER]

High-speed X-ray imaging applications play a crucial role for non-destructive investigations of the dynamics in material science and biology. On-line data analysis is necessary for quality assurance and data-driven feedback, leading to a more efficent use of a beam time and increased data quality. In this article we present a smart camera platform with embedded Field Programmable Gate Array (FPGA) processing that is able to stream and process data continuously in real-time. The setup consists of a Complementary Metal-Oxide-Semiconductor (CMOS) sensor, an FPGA readout card, and a readout computer. It is seamlessly integrated in a new custom experiment control system called Concert that provides a more efficient way of operating a beamline by integrating device control, experiment process control, and data analysis. The potential of the embedded processing is demonstrated by implementing an image-based trigger. It records the temporal evolution of physical events with increased speed while maintaining the full field of view. The complete data acquisition system, with Concert and the smart camera platform was successfully integrated and used for fast X-ray imaging experiments at KIT’s synchrotron radiation facility ANKA. [ABSTRACT FROM PUBLISHER]

We present a method to calculate the harmonic spectrum of the radiation emitted at the interactions between intense laser beams and atoms. Our relations describe accurately, in good agreement with the experiment, important features of the harmonic spectrum and the evolution of its shape with the increase of the laser beam intensity. More specifically, for low intensities, of the order of 10^13~W/cm^2, the spectrum has the well-known plateau shape, after which follows a sharp decrease at the cutoff edge. When the beam intensity is increased, toward 10^15~W/cm^2, the slope of the plateau increases, corresponding to a decrease by one or two orders of magnitude of the harmonic intensities. When the beam intensity is increased more, toward 10^17~W/cm^2, there is a maximum at the left edge of the spectrum, which is followed by a strong decrease of many orders of magnitude, and the spectrum concentrates in a very limited domain, under a certain frequency, far lower than the theoretical cutoff frequency. These theoretical results are in good agreement with numerous experimental data from the literature, for many atoms and ions, and for a large spectrum of intensities of laser beams. This result has important implications in the emerging field of generation of high intensity hard X-rays. [ABSTRACT FROM PUBLISHER]

Three-dimensional (3D) photodiode detectors offer advantages over standard planar photodiodes in a range of applications, including X-ray detection for synchrotrons and medical imaging. The principal advantage of these sensors for X-ray imaging is their low charge sharing between adjacent pixels, which could improve spatial and spectral resolution. A 'double-sided' 3D detector has been bonded to a Medipix2 single-photon-counting readout chip, and tested in a monochromatic X-ray beam at the Diamond synchrotron. Tests of the 3D detector's response spectrum and its Line Spread Function have shown that it has substantially lower charge sharing than a standard planar Medipix2 sensor. Additionally, the 3D detector was used to image diffraction rings produced by a powdered silicon sample, demonstrating the detector's use in a standard synchrotron experiment. [ABSTRACT FROM AUTHOR]

The article discusses research on knowledge-assisted 3-dimension (3D) rib cage and lung reconstruction algorithms that can help in the early detection of diseases at a lower cost. The unique approach is combining the use of expert knowledge in modeling techniques, knowledge of the human ribs and lung shapes and having the information that segmentation can extract from the x-ray images. Visualizations through rotating the volumetric lungs can help physicians notice the subtle oddities that may be overlooked when evaluating 2-dimension 2D x-ray images.

A highly sensitive detection system for magnetic contaminants using a High-Tc superconducting quantum interference device (SQUID) was developed. Finding ultra-small metallic contaminants is a big issue for manufacturers producing commercial products such as lithium ion batteries. When the contamination does occur, the manufacturer of the product suffers a great loss to recall the tainted products. The outer dimension of metallic particles less than 100 microns can not be detected by X-ray imaging, which is commonly used as the inspection method. Inmost cases, the matrix of industrial products is magnetized and the magnetic signal from the matrix is large enough to mask the signal from contaminants. We developed a detection system based on a high-Tc SQUID gradiometer. A specially designed low noise planar gradiometer for the system was developed. The flux white noise level of the SQUID gradiometer was 8-16μø0/Hz1/2 at 1 kHz. Use of the gradiometer and horizontal magnetization could solve problem above. We tested the performances of the system and found that small iron particles as small as 50 μm × 50 μm on the electrode of the lithium ion battery could be clearly detect. This detection level is difficult to achieve using other methods. [ABSTRACT FROM AUTHOR]

Caliste project aims at hybridizing 1 cm² Cd(Zn)Te detectors with low noise front-end electronics, in a single component standing in a 1 × 1 × 2 cm³ volume. The micro-camera is a spectroscopic imager for X and gamma rays detection, with time-tagging capability. Hybridization consists in stacking full custom ASICs perpendicular to the detection surface. The first prototype Caliste 64 integrates a detector of 8 × 8 pixels of! mm pitch. Fabrication and characterizations of nine cameras units validate the design and the hybridization concept. Spectroscopic tests result in a mean energy resolution of ≈0.7 keV FWHTM at 14 keV and ∼0.85 keV FWHM at 60 keV using 1 mm-thick Al Schottky CdTe detectors biased at -400 V and cooled down to -15 °C. The new prototype called Caliste 256 integrates 16 × 16 pixels of 580 μm pitch in the same volume as Caliste 64. Electrical tests with the first sample fabricated without detector result in a mean equivalent noise charge of 64 e- rms (9.6 μs, no leakage current). Caliste devices are 4-side buttable and can be used as elementary detection units of a large hard X-ray focal plane, as for the 64 cm² high energy detector of the Simbol-X astronomical space mission. [ABSTRACT FROM AUTHOR]

The National Space Institute, of the Technical University of Denmark is responsible for the selection and characterization of the CZT detector crystals for the X- and Gamma-ray instrument, MXGS, onboard ESA's Atmospheric Space Interaction Monitor (ASIM) mission. The first CZT pixel detector modules for MXGS have recently been delivered by Redlen. Measurements at the University of Bergen demonstrate that the detectors exhibit the expected spectral performance; however, it was also found that the detector modules showed unexplained pixel-to-pixel count rate variations. At The National Space Institute a series of measurements were initiated focusing on the pixel-to-pixel count rate variations. Collimated monochromatic X-ray beams were used to scan a number of Redlen pixel detectors. The main conclusion of these measurements is that the pixel-to-pixel count rate variations are correlated with variations in the effective pixel areas. These variations are likely related to non-uniformity of the internal electric detector field. [ABSTRACT FROM AUTHOR]

CdTe thick films were prepared by vacuum deposition on amorphous substrates using MIBE technique. The growth was performed at different temperatures to investigate the development of the growth rate, surface morphology, structure and optical properties. Properties of films deposited with a single CdTe source are compared with films grown with an additional Cd source. The growth experiments are discussed with regard to demands for X-ray detector applications. [ABSTRACT FROM AUTHOR]

This paper considers the problem of container inspection at a port-of-entry. Containers are inspected through a specific sequence to detect the presence of nuclear materials, biological and chemical agents, and other illegal shipments. The threshold levels of sensors at inspection stations of the port-of-entry affect the probabilities of incorrectly accepting or rejecting a container. In this paper, we present several optimization approaches for determining the optimum sensor threshold levels, while considering misclassification errors, total cost of inspection, and budget constraints. In contrast to previous work which determines threshold levels and sequence separately, we consider an integrated system and determine them simultaneously. Examples applying the approaches in different sensor arrangements are demonstrated. [ABSTRACT FROM AUTHOR]

A CMOS charge readout ASIC (SD7110) for flat-panel X-ray detectors was designed and tested. This ASIC contains 128 readout channels, with each channel consisting of a charge sensitive amplifier, a correlated double sampler, and a track-and-hold circuit. Channel outputs are read out via a 128:1 analog multiplexer and fed into an external 16-bit A/D converter. Conversion gain can be selected from 0.25 V/pC to 8 V/pC. The ASIC operates using a +5.0 V single power supply, with power dissipation of 1.8 mW/channel. The equivalent noise charge (ENC) measured was 400 + 18.9 e-/pF. [ABSTRACT FROM AUTHOR]

The article presents information on the X-ray scanners which help in detecting illegitimate materials because of their ability to identify any substance such as explosives at the molecular and atomic levels. It is also because of its less expensive cost that the technology is used extensively. However, the R-L technology created at the Virginia Tech University is considered the first multisensing technology used to detect explosives.

This paper presents a newly developed 3-Dimensional (3-D) simulation system for Moving Mask Deep X-ray Lithography (M²DXL) technique, and its validation. The simulation system named X-ray Lithography Simulation System for 3-Dimensional Fabrication (X3D) is tailored to simulate a fabrication process of 3-D microstructures by M²DXL. X3D consists of three modules: mask generation, exposure and resist development (hereafter development). The exposure module calculates a dose distribution in resist using an X-ray mask pattern and its movement trajectory. The dose is then converted to a resist dissolution rate. The development module adopted the "Fast Marching Method" technique to calculate the 3-D dissolution process and resultant 3-D microstructures. This technique takes into account resist dissolution direction that is required by 3-D X-ray lithography simulation. The comparison between simulation results and measurements of "stairs-like" dose deposition pattern by M²DXL showed that X3D correctly predicts the 3-D dissolution process of exposed PMMA. [ABSTRACT FROM AUTHOR]

Low-voltage operation of millimeter-wave folded waveguide traveling-wave tube (TWT) was investigated using a 12 kV linear electron beam. Backward wave oscillation operated at second space harmonic was observed with output power of 20 W, linear tunability of 6% within 0.01 dB/MH.z, and voltage-frequency stability of 0.56 MHz/V The measured frequency and output power are in a good agreement with the predicted values using a particle-in-cell (PlC) code. In addition, backward-wave interaction at second-space harmonic as an amplifier was observed with a measured linear gain of 15 dB and a bandwidth of 03%. For forward wave Interaction, a linear gain of 25 dB, bandwidth of 17%, and efficiency of 7% were predicted for fundamental space harmonic using a PlC code. Improvement In efficiency was predicted for the forward-wave amplifier where It was operated as an oscifiator employing a delayed feedback. Output power was increased by 10 dB in the delayed feedback oscillator comparing with the backward-wave oscillator. The effect of period doubling due to potential fabrication inaccuracies on the stopband was studied experimentally. The folded waveguide TWT fabricated using the Lighographie, Galvanoformung, Abformung (LIGA) process operated at much higher frequencies is discussed. [ABSTRACT FROM AUTHOR]

Explores the efficacy of treating Escherichia coli O157:H7 in ground beef by irradiating frozen ground beef with high-dose-rate X-rays. Selection and description of accelerator; Preparation of beef samples; Discussion of the experimental protocol.

Reports that an x-ray emission computed tomography technique was demonstrated to diagnose the laser implosion uniformity of spherical targets. Method by which three-dimensional images were reconstructed; Capability of the imaging system.