RadiaBeam has developed a 6 MeV accelerator that is compact and light enough to be placed on a robotic arm or light truck. The main drivers of size and weight in conventional accelerators are the power source and the shielding. Small dimensions are enabled by operation at 9.3 GHz frequency (X-band), which allows reducing the size and weight of all accelerator components. Thanks to the robust design of the accelerating structure, the accelerator can be used as a source for novel cargo inspection and radiotherapy techniques. In this paper, we present the linac design and its components, as well the results of the experimental demonstration of beam acceleration.

X-ray imaging techniques based on Compton backscatter allow inspection and screening of a variety of vehicles, cargo containers, luggage, suspicious packages, aircraft and spacecraft components, as well as building walls and floors. Backscatter imaging systems are in wide use by government agencies, border authorities, law enforcement personnel, military organizations, and security services in many countries.In contrast to commonly used transmission inspection systems, backscatter imaging involves positioning both radiation source and detectors on the same side of a target object. Such systems are exceptionally useful in situations where access to the inspected object is limited to a single side, making X-ray transmission systems impractical.Conventional backscatter inspection systems have a significant limitation in their ability to penetrate even moderately dense objects. Moreover, the signal is dominated by the front interrogated layer, e.g., the metal wall of a container or vehicle, or the front layer of wall. To overcome this fundamental limitation, we develop an advanced inspection technique, DeepBx, which uses energy- and current- modulated X-ray pulses; fast, time-resolving X-ray detectors; and an image "peeling" processing algorithm.This publication presents the results of a simulation of the DeepBx approach and testing of a lab prototype of the DeepBx Imager, configured for the of detection of prohibited substances hidden in a wall phantom. These results are compared with conventional backscatter imaging approaches.

RadiaBeam has developed a novel, flexible linac for electrons and X-rays (FLEX) capable of energy variation from 2 to 9 MeV within a single RF pulse. This accelerator employs a robust traveling wave accelerating structure with a large energy and power acceptance that allows the unique features of deep energy and current variation required for novel adaptive cargo inspection techniques and Computed Tomography. Robust RF and water-cooling systems allow average beam powers up to 15 kW, upgradable to 57 kW, at 6 MeV, potentially making this accelerator useful for electron beam irradiation applications. The high peak currents of the electron beam produced by FLEX enable novel FLASH radiotherapy methods with fast dose delivery. In this paper, we present the linac design and its components, as well the results of the experimental demonstration of beam acceleration with energy variation.

The IOTA ring at Fermilab is a unique machine exclusively dedicated to accelerator beam physics R&D. The research conducted at IOTA includes topics such as nonlinear integrable optics, suppression of coherent beam instabilities, optical stochastic cooling, and quantum science experiments. Here we report on the first results of experiments with implementations of nonlinear integrable beam optics. The first of its kind practical realization of a two-dimensional integrable system in a strongly-focusing storage ring was demonstrated allowing among other things for stable beam circulation near or at the integer resonance. Also presented are the highlights of the world’s first demonstration of optical stochastic beam cooling and other selected results of IOTA’s broad experimental program.

This paper provides a brief overview of new screening methods that employ Modulated-Energy X-ray Pulses (MEXP) to provide a number of near-simultaneous multi-energy measurements in transmission-, backscatter-, and Computed Tomography (CT) security systems. In transmission X-ray cargo screening, these multi-energy measurements improve material discrimination, maximize penetration, and enhance contrast resolution while simultaneously reducing inspection time and dose to the environment, thus resulting in a smaller exclusion zone. In backscatter systems, the use of this method will increase penetration and improve image quality of concealed objects located deeper below the surface. Specifically, different depths within an object can be probed simultaneously. In CT, our MEXP approach mitigates the main disadvantages of the conventional dual-energy technique: a) distortion of image of the boundaries between regions with large difference in density; b) limited range of object thickness where material decomposition is valid; c) ambiguity and artifacts caused by sampling different regions due to motion of the object between interlaced pulses with distinct energies. Results of testing of the prototype of high speed Adaptive, Multi-Energy Cargo Inspection System (AMEXIS) will be presented. Progress in the development of MEXP-based backscatter inspection system, and systems for cargo screening with Adaptive CT will also be shown.

RadiaBeam Technologies, LLC has developed an inexpensive, hand-portable 180 keV electron accelerator to replace Co-57 radionuclide sources in Cascade Header Enrichment Monitor detectors. We used two innovative technologies in our design: a Ku-band (1 cm wavelength) magnetron, and a split accelerating structure design to reduce manufacturing costs. In this paper, we will discuss the accelerator, including X-ray convertor and accelerating structure design. The results of RF measurements of a Ku-band split structure prototype will also be reviewed. Other applications of Ku-band linacs include compact backscatter and transmission X-ray security inspection systems, as well as computed tomography (CT) systems for luggage and parcel screening. The main requirement for luggage inspection systems is that the X-ray source must be extremely compact. Further, the required energies should cover the range from 180 keV to 1 MeV. In this paper, we will discuss the linac's energy scalability and other modifications that will enable our technology to address these applications.

A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.

X-ray multi-energy adaptive security radiography and computed tomography inspection techniques have superior performance compared to conventional dual-energy methods where two image slices are acquired by alternating energies. This new technique allows improving the quality of radiographic and CT images, expanding the range of areal densities of the interrogated objects over which effective discrimination of materials by atomic number is possible, eliminating artifacts in the image of boundaries of different densities, and reducing the time of inspection and the required dose. For this new inspection technology, RadiaBeam Technologies is developing several new types of x-ray sources that are based on linear electron accelerators. To provide an adaptive mode of operation of inspection systems, such accelerators use fast feedback from the detector array. Depending on the application, the range of the electron energy can vary from 180 keV up to 9 MeV. In this paper, we discuss the requirements for such linear accelerators, some details about their designs, and present the results of high-power and beam testing of the S- and X-band accelerators.

One of the main factors limiting the performance of conventional x-ray cargo inspection with material discrimination (MD) is the interlaced mode of system operation. Such systems use pulsed linac or betatron x-ray generators and produce alternate bremsstrahlung pulses with lower- and higher- end-point energies. Consequently, these systems provide about 50 mm lower penetration than a system operated in a non-interlaced mode, have a limited range of cargo areal densities with valid MD, and cannot perform MD of objects smaller than the pulse separation. Also, the limited pulse repetition rate of x-ray generators in interlaced mode limits the radiographic image quality at nominal commercial speeds of vehicles or trains. Several new methods of cargo inspection with MD were recently introduced to address the above-mentioned limitations: dual energy methods based on Scintillation-Cherenkov detectors [1]; multi-energy method based on intrapulse time-varying of spectral content of x-ray [1, 2]; multi-energy method utilized ramping-up energy packet of short x-ray pulses [3, 4]; and methods based on multi-energy betatron [5, 6]. All of these methods have electron accelerators as a core element. However, the accelerator requirements and, thus, their designs, are different for each system. In this paper, we will discuss the requirements for the accelerators, provide some details about their designs, and present several novel solutions for current and future projects. 2017 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of the Conference on the Application of Accelerators Research and Industry.

Novel radiographic imaging techniques [1] based on adaptive, intra-pulse ramped-energy short X-ray packets of pulses, a new type of fast X-ray detectors, and advanced image processing are currently some of the most promising methods for real-time cargo inspection systems. RadiaBeam Technologies is developing the high-speed Adaptive Railroad Cargo Inspection System (ARCIS), which will enable better than 5 mm line pair resolution, penetration greater than 450 mm of steel equivalent, material discrimination over the range of 6 mm to 250 mm, 100% image sampling rate at speed up to 45 km/h, and minimal average dose. One of the core elements of ARCIS is a new S-band travelling wave linac with a broad range of energy control. The linac allows energy ramping from 2 to 9 MeV within a single 16 μs RF pulse using the beam loading effect. RadiaBeam Technologies has designed, built and tested the ARCIS accelerator prototype. In this paper, we will discuss the linac design approach and its principal components. The results of the experimental demonstration of intra-pulse energy ramping will be presented. We will also provide a detailed comparison of beam dynamics simulations in Hellweg2D and CST Studio codes with experimental measurements, including transient beam loading effects.

A novel, low-dose Mobile Intelligent X-ray Inspection (MIXI) concept is being developed at RadiaBeam Technologies. The MIXI concept relies on a linac-based, adaptive, ramped energy source of short X-ray packets of pulses, a new type of fast X-ray detector, rapid processing of detector signals for intelligent control of the linac, and advanced radiography image processing. The key parameters for this system include: better than 3 mm line pair resolution; penetration greater than 320 mm of steel equivalent; scan speed with 100% image sampling rate of up to 15 km/h; and material discrimination over a range of thicknesses up to 200 mm of steel equivalent. Its minimal radiation dose, size and weight allow MIXI to be placed on a lightweight truck chassis.

X-ray Computed Tomography (CT) is a widely used tool for security and industrial non-destructive testing (NDT). Scanned objects in these uses typically contain multiple materials with different atomic numbers. In these cases, Dual-Energy CT (DECT) has numerous advantages over conventional single-energy CT, including improved image quality, reduction of effect of scatter and other artefacts, and better material decomposition. Therefore, DECT has become the standard for inspection of objects containing multiple materials [1–2]. In this paper, we present a new CT technology: Adaptive Computed Tomography with Modulated-energy X-ray pulses (ACTM) [3]. ACTM is based on adaptive cargo radiography techniques [4–6] that have been developed over the last few years. To perform CT imaging, we propose to utilize the exact and fast Katsevich image reconstruction algorithm [7–12].Key enabling ACTM techniques are:•Linear accelerator with deep energy control.•Multi-energy spectrum in each slice provided by packets of short X-ray pulses with end-point energy ramp up (> 1 MHz rate of energy switching).•Fast detectors with reduced sensitivity to scatter radiation.•Detector readout with silicon photomultipliers (SiPM) provides time-resolved measurement of short X-ray pulses.•Electronics and an algorithm for automatic, dynamic adjustment of SiPM responsivity in detector channels provides increased dynamic range of X-ray imaging.•Real-time algorithm for X-ray pulse-by-pulse selection of high and low energy windows for dual-energy material decomposition.•Filtered Backprojection (FBP) helical image reconstruction based on the theoretically exact Katsevich algorithm.The ACTM method for dual- (or, multi-) energy CT mitigates the main disadvantages of the conventional interlaced approach:•Ambiguity and artifacts caused by sampling different regions due to motion of the object between interlaced pulses with distinct energies.•Distortion of CT image of the boundaries between regions with large difference in Z.•Small range of object thicknesses where material decomposition is valid.

The security market requirements for state-of-the-art mobile and portal radiography inspection systems include high imaging resolution (better than 5 mm line pair), penetration beyond 300 mm steel equivalent, material discrimination (three groups of Z) at speeds up to 16 km/h with 100% image sampling, low dose and small radiation exclusion zone. New research into radiography methods and systems has been actively pursued in order to achieve these challenging requirements. Recently, a significant portion of the R&D effort has been devoted to re-examining betatron based X-ray inspection systems. The advantages of the betatron-based inspection systems over conventional linac-based designs include small focal spot (which improves resolution), low weight and form-factor, a simpler control system and relatively low cost.A novel, low-dose Multi-Energy Betatron-based Cargo Inspection System, MEBCIS, presented in this paper relies on an innovative technique of extracting two X-ray pulses with lower-and higher-energies within a single betatron acceleration cycle (in contrast to conventional dual-energy betatrons with one Xray pulse produced during separate betatron acceleration cycles). In addition to the new betatron, new types of fast X-ray Scintillation-Cherenkov detectors, rapid processing of detector signals, an adaptive detector feedback algorithm for control of the betatron, and algorithms for intelligent material discrimination are parts of the overall MEBCIS system.The key advantage of the MEBCIS concept is that the material discrimination data is acquired in a single scan line rather than two. Thus, for the same betatron pulse rate, the scan rate can be twice as fast (better throughput) or can be done with a lower dose, even without adaptive dynamic pulse adjustment.Application of these techniques will maximize material discrimination, penetration, and contrast resolution while simultaneously reducing dose to the environment, resulting in a smaller exclusion zone. Its minimal size and weight will allow MEBCIS to be placed on a lightweight truck chassis.

A novel high speed Adaptive Railroad Cargo Inspection System (ARCIS) is being developed at RadiaBeam Technologies. The ARCIS concept relies on linac-based, adaptive, ramped energy source of short X-ray packets of pulses, a new type of fast X-ray detectors, rapid processing of detector signals for intelligent control of the linac, and advanced radiography image processing. The requirements for this system include better than 5 mm line pair resolution, penetration greater than 400 mm of steel equivalent, scan speeds up to 60 km/h, material discrimination within 100% of image and minimal average dose. To meet these requirements a new S-band travelling wave linac with deep energy control has been designed. This paper discusses the linac design approach and its principal components, as well as engineering and manufacturing aspects.

Recently Silicon Photomultipliers (SiPMs) have become well recognized as the detector of choice for various applications which demand good photon number resolution and time resolution of short weak light pulses in the nanosecond time scale. In the case of longer and more intensive light pulses, SiPM performance gradually degrades due to dark noise, afterpulsing, and non-instant cell recovering. Nevertheless, SiPM benefits are expected to overbalance their drawbacks in applications such as X-ray cargo inspection using Scintillation-Cherenkov detectors and accelerator beam loss monitoring with Cherenkov fibres, where light pulses of a microsecond time scale have to be detected with good amplitude and timing resolution in a wide dynamic range of 105–106.

The security market requirements for high throughput rail cargo radiography inspection systems include better than 5 mm line pair imaging resolution, penetration beyond 400 mm steel equivalent, scan speeds of up to 60 km/h, material discrimination (four groups of Z) in 100 % of cargo at speeds reaching 45 km/h, low dose and small radiation exclusioi zone. In order to achieve these requirements, which cannot be met by conventional dual energy radiography systems, a team lead by RadiaBeam Technologies, LLC (RBT) has initiated a research into new radiography methods and imaging detector materials with the goal of developing an Adaptive Railroad Cargo Inspection System (ARCIS). The ARCIS technical concept relies on linac-based, adaptive, ramped energy source of packets of short X-ray pulses sampled by a new type of fast X-ray detectors with rapid hardware processing for intelligent linac control, and advanced radiography image processing and material discrimination analysis. The following ARCIS key enabling technologies overcome the limitations of the conventional dual energy interlaced cargo inspection systems: Multi-energy material discrimination in a single scan line provided by packets of short pulses from an X-ray source with end-point energy ramp up (> 1 MHz rate of energy switching); Real-time intelligent setting of packet's maximum energy depend on X-ray attenuation in cargo; Fast Scintillation-Cherenkov detectors with reduced sensitivity to scatter radiation; Detector readout with Silicon Photomultiplier (SiPM) provides time-resolving of short X-ray pulses; Self-control adaptive dynamic adjustment of SiPM responsivity in detector channel for increased dynamic range.

The World Wide Student Laboratory, WWSL, is an innovative advance in the delivery of science and engineering education over the Internet. The WWSL allows students anywhere in the world to control advanced experiments in remote locations and to have access to equipment that would otherwise be unavailable. Using the WWSL, students perform experiments with real experimental setups and, under the guidance of their professor, teacher, or instructor, collect real data for analysis. The WWSL can serve traditional universities, colleges and high schools, as well as distance education institutions. With the WWSL's new approach, educational institutions will be able to afford better facilities for the education they provide, access the best lab facilities in other institutions, and substantially broaden the number of lab study items in their curriculum. Using the WWSL Internet portal, students will access the individual laboratory setups by means of “web centers” arranged by topic – Topical Group Web Centers. The WWSL also brings greater economic efficiency to existing university laboratories by eliminating instrumental downtime and creating a revenue source to offset purchase and maintenance costs, while improving the educational experience.