This PDF file contains the front matter associated with SPIE Proceedings Volume 10393, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Energy dispersive X-ray diffraction (EDXRD) can be applied for identification of liquid threats in luggage scanning in security applications. To define the instrumental design, the framework for data reduction and analysis and test the performance of the threat detection in various scenarios, a flexible laboratory EDXRD test setup was build. A data set of overall 570 EDXRD spectra has been acquired for training and testing of threat identification algorithms. The EDXRD data was acquired with limited count statistics and at multiple detector angles and merged after correction and normalization. Initial testing of the threat detection algorithms with this data set indicate the feasibility of detection levels of > 95 % true positive with < 6 % false positive alarms.

Trace quantities of a uranyl dissolved in water were measured using a simple optical method. A dilute solution of uranium nitrate dissolved in water was forced through nanoporous silica gel at fixed and controlled water flow rates. The uranyl ions deposited and accumulated within the silica gel and the uranyl fluorescence within the silica gel was monitored as a function of time using a light emitting diode as the excitation source and a photomultiplier tube detector. It was shown that the response time of the fluorescence output signal at a particular volumetric flow rate or average liquid velocity through the silica gel can be used to quantify the concentration of uranium in water. The response time as a function of concentration decreased with increasing flow velocity.

For nuclear disasters involving radioactive contamination, small unmanned aircraft systems (sUASs) equipped with nuclear radiation detection and monitoring capability can be very important tools. Among the advantages of a sUAS are quick deployment, low-altitude flying that enhances sensitivity, wide area coverage, no radiation exposure health safety restriction, and the ability to access highly hazardous or radioactive areas. Additionally, the sUAS can be configured with the nuclear detecting sensor optimized to measure the radiation associated with the event. In this investigation, sUAS platforms were obtained for the installation of sensor payloads for radiation detection and electro-optical systems that were specifically developed for sUAS research, development, and operational testing. The sensor payloads were optimized for the contour mapping of a nuclear radiation field, which will result in a formula for low-cost sUAS platform operations with built-in formation flight control. Additional emphases of the investigation were to develop the relevant contouring algorithms; initiate the sUAS comprehensive testing using the Unmanned Systems, Inc. (USI) Sandstorm platforms and other acquired platforms; and both acquire and optimize the sensors for detection and localization. We demonstrated contour mapping through simulation and validated waypoint detection. We mounted a detector on a sUAS and operated it initially in the counts per second (cps) mode to perform field and flight tests to demonstrate that the equipment was functioning as designed. We performed ground truth measurements to determine the response of the detector as a function of source-to-detector distance. Operation of the radiation detector was tested using different unshielded sources.

This article describes the International Radiation Monitoring Information System (IRMIS) which was developed by the International Atomic Energy Agency (IAEA) with the goal to provide Competent Authorities, the IAEA and other international organizations with a client server based web application to share and visualize large quantities of radiation monitoring data. The data maps the areas of potential impact that can assist countries to take appropriate protective actions in an emergency.

Ever since the Chernobyl nuclear power plant accident in April of 19861 European Community (EC) has worked towards collecting routine environmental radiological monitoring data from national networked monitoring systems. European Radiological Data Exchange Platform (EURDEP) was created in 19952 to that end – to provide radiation monitoring data from most European countries reported in nearly real-time.

During the response operations for the Fukushima Dai-ichi nuclear power plant accident (March 2011) the IAEA Incident and Emergency Centre (IEC) managed, harmonized and shared the large amount of data that was being generated from different organizations. This task underscored the need for a system which allows sharing large volumes of radiation monitoring data in an emergency.

In 2014 EURDEP started the submission of the European radiological data to the International Radiation Monitoring Information System (IRMIS) as a European Regional HUB for IRMIS. IRMIS supports the implementation of the Convention on Early Notification of a Nuclear Accident by providing a web application for the reporting, sharing, visualizing and analysing of large quantities of environmental radiation monitoring data during nuclear or radiological emergencies.

IRMIS is not an early warning system that automatically reports when there are significant deviations in radiation levels or when values are detected above certain levels. However, the configuration of the visualization features offered by IRMIS may help Member States to determine where elevated gamma dose rate measurements during a radiological or nuclear emergency indicate that actions to protect the public are necessary. The data can be used to assist emergency responders determine where and when to take necessary actions to protect the public.

This new web online tool supports the IAEA’s Unified System for Information Exchange in Incidents and Emergencies (USIE)3, an online tool where competent authorities can access information about all emergency situations, ranging from a lost radioactive source to a full-scale nuclear emergency.

The Collimated Directional Radiation Detection System (CDRDS) is capable of imaging radioactive sources in two dimensions (as a directional detector). The detection medium of the CDRDS is a single Cs₂LiYCl₆:Ce³⁺ scintillator cell enriched in ⁷Li (CLYC-7). The CLYC-7 is surrounded by a heterogeneous high-density polyethylene (HDPE) and lead (Pb) collimator. These materials make-up a coded aperture inlaid in the collimator. The collimator is rotated 360° by a stepper motor which enables time-encoded imaging of a radioactive source. The CDRDS is capable of spectroscopy and pulse shape discrimination (PSD) of photons and fast neutrons.

The measurements of a radioactive source are carried out in discrete time steps that correlate to the angular rotation of the collimator. The measurement results are processed using a maximum likelihood expectation (MLEM) algorithm to create an image of the measured radiation.

This collimator design allows for the directional detection of photons and fast neutrons simultaneously by utilizing only one CLYC-7 scintillator. Directional detection of thermal neutrons can also be performed by utilizing another suitable scintillator. Moreover, the CDRDS is portable, robust, and user friendly. This unit is capable of utilizing wireless data transfer for possible radiation mapping and network-centric applications. The CDRDS was tested by performing laboratory measurements with various gamma-ray and neutron sources.

The recent reduction of dark current in Silicon Solid-state photomultipliers (SiSSPMs) makes them an attractive alternative to conventional photomultiplier tubes (PMTs) for scintillation detection applications. Nuclear Physics experiments often require large detector volumes made using scintillation materials, which require sensitive photodetectors, such as a PMTs. PMTs add to the size, fragility, and high-voltage requirements as well as distance requirements for experiments using magnetic fields. This work compares RMD’s latest detector modules, denoted as the “year 2 prototype”, of plastic scintillators that discriminate gamma and high-energy particle events from neutron events using pulse shape discrimination (PSD) coupled to a SiSSPM to the following two detector modules: a similar “year 1 prototype” and a scintillator coupled to a PMT module. It characterizes the noise floor, relative signal-to-noise ratio (SNR), the timing performance, the PSD figure-of-merit (FOM) and the neutron detection efficiency of RMD’s detectors. This work also evaluates the scaling of SiSSPM detector modules to accommodate the volumes needed for many Nuclear Physics experiments. The Si SSPM detector module provides a clear advantage in Nuclear Physics experiments that require the following attributes: discrimination of neutron and gamma-ray events, operation in or near strong magnetic fields, and segmentation of the detector.

We demonstrate very high–resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor (TES) array. The readout circuit consists of superconducting microwave resonators coupled to radio frequency superconducting-quantum-interference devices (RF-SQUIDs) and transduces changes in input current to changes in phase of a microwave signal. We used a flux-ramp modulation to linearize the response and avoid low-frequency noise. The result is a very high-resolution photon spectroscopy with a microwave-multiplexed 4-pixel transition edge sensor array. We performed and validated a small-scale demonstration and test of all the components of our concept system, which encompassed microcalorimetry, microwave multiplexing, RF-SQUIDs, and software-defined radio (SDR). We shall display data we acquired in the first simultaneous combination of all key innovations in a 4-pixel demonstration, including microcalorimetry, microwave multiplexing, RF-SQUIDs, and SDR. We present the energy spectrum of a gadolinium-153 (¹⁵³Gd) source we measured using our 4-pixel TES array and the RF-SQUID multiplexer. For each pixel, one can observe the two 97.4 and 103.2 keV photopeaks. We measured the ¹⁵³Gd photon source with an achieved energy resolution of 70 eV, full width half maximum (FWHM) at 100 keV, and an equivalent readout system noise of 90 pA/pHz at the TES. This demonstration establishes a path for the readout of cryogenic x-ray and gamma ray sensor arrays with more elements and spectral resolving powers. We believe this project has improved capabilities and substantively advanced the science useful for missions such as nuclear forensics, emergency response, and treaty verification through the explored TES developments.

Single sided radiographic imaging would find great utility for medical, aerospace and security applications. While coded apertures can be used to form such an image from backscattered X-rays they suffer from near field limitations that introduce noise. Several theoretical studies have indicated that for an extended source the images signal to noise ratio may be optimised by using a low open fraction (<0.5) mask. However, few experimental results have been published for such low open fraction patterns and details of their formulation are often unavailable or are ambiguous. In this paper we address this process for two types of low open fraction mask, the dilute URA and the Singer set array. For the dilute URA the procedure for producing multiple 2D array patterns from given 1D binary sequences (Barker codes) is explained. Their point spread functions are calculated and their imaging properties are critically reviewed. These results are then compared to those from the Singer set and experimental exposures are presented for both type of pattern; their prospects for near field imaging are discussed.

Our team at Los Alamos National Laboratory has successfully employed Compton spectrometers to measure the X-ray spectra of both continuous and flash radiographic sources. In this method, a collimated beam of X-rays incident on a converter foil ejects Compton electrons. A collimator may be inserted into the entrance of the spectrometer to narrow the angular acceptance of the forward-scattered electrons, which then enter the magnetic field region of the spectrometer. The position of the electrons at the magnet’s focal plane is proportional to the square root of their momentum, allowing the X-ray spectrum to be reconstructed. A new samarium-cobalt spectrometer with an energy range of 50 keV to 4 MeV has been fielded at two facilities. The X-ray generating machines produced intense photon beams (> 4 rad at 1 m) with spectral endpoints below 3 MeV. Recent experimental results will be presented.

We present a TCAD simulation-based investigation of charge transport and charge collection mechanisms of a pinned photodiode pixel for X-ray imaging. Following static simulations to determine the electric-field and potential profiles, charge collection was analyzed with transient numerical simulations. A new, simple and computationally affordable calculation based on the extension of Ramo's theorem to account for carrier diffusion is proposed to estimate the trajectories of the generated carriers and the corresponding currents at the device terminals. The new method is validated and successfully compared to the time-dependent TCAD simulations of a p-i-n diode and a template 3D pinned photodiode.

A multi-purpose readout electronics based on the DPLMS digital filter has been developed for CdTe and CZT detectors for X-ray imaging applications. Different filter coefficients can be synthesized optimized either for high energy resolution at relatively low counting rate or for high rate photon-counting with reduced energy resolution. The effects of signal width constraints, sampling rate and length were numerical studied by Mento Carlo simulation with simple CRRC shaper input signals. The signal width constraint had minor effect and the ENC was only increased by 6.5% when the signal width was shortened down to 2 τ_c. The sampling rate and length depended on the characteristic time constants of both input and output signals. For simple CR-RC input signals, the minimum number of the filter coefficients was 12 with 10% increase in ENC when the output time constant was close to the input shaping time. A prototype readout electronics was developed for demonstration, using a previously designed analog front ASIC and a commercial ADC card. Two different DPLMS filters were successfully synthesized and applied for high resolution and high counting rate applications respectively. The readout electronics was also tested with a linear array CdTe detector. The energy resolutions of Am-241 59.5 keV peak were measured to be 6.41% in FWHM for the high resolution filter and to be 13.58% in FWHM for the high counting rate filter with 160 ns signal width constraint.

Many different mask patterns can be used for X-ray backscatter imaging using coded apertures, which can find application in the medical, industrial and security sectors. While some of these patterns may be considered to have a self-supporting structure, this is not the case for some of the most frequently used patterns such as uniformly redundant arrays or any pattern with a high open fraction. This makes mask construction difficult and usually requires a compromise in its design by drilling holes or adopting a no two holes touching version of the original pattern. In this study, this compromise was avoided by 3D printing a support structure that was then filled with a radiopaque material to create the completed mask. The coded masks were manufactured using two different methods, hot cast and cold cast. Hot casting involved casting a bismuth alloy at 80°C into the 3D printed acrylonitrile butadiene styrene mould which produced an absorber with density of 8.6 g cm^-3. Cold casting was undertaken at room temperature, when a tungsten/epoxy composite was cast into a 3D printed polylactic acid mould. The cold cast procedure offered a greater density of around 9.6 to 10 g cm^-3 and consequently greater X-ray attenuation. It was also found to be much easier to manufacture and more cost effective. A critical review of the manufacturing procedure is presented along with some typical images. In both cases the 3D printing process allowed square apertures to be created avoiding their approximation by circular holes when conventional drilling is used.

Sandia National Laboratories has recently developed the capability to acquire multi-channel radio- graphs for multiple research and development applications in industry and security. This capability allows for the acquisition of x-ray radiographs or sinogram data to be acquired at up to 300 keV with up to 128 channels per pixel. This work will investigate whether multiple quality metrics for computed tomography can actually benefit from binned projection data compared to traditionally acquired grayscale sinogram data. Features and metrics to be evaluated include the ability to dis- tinguish between two different materials with similar absorption properties, artifact reduction, and signal-to-noise for both raw data and reconstructed volumetric data. The impact of this technology to non-destructive evaluation, national security, and industry is wide-ranging and has to potential to improve upon many inspection methods such as dual-energy methods, material identification, object segmentation, and computer vision on radiographs.

Compared to the dual energy scintillator detectors widely used today, pixelated multispectral X-ray detectors show the potential to improve material identification in various radiography and tomography applications used for industrial and security purposes. However, detector effects, such as charge sharing and photon pileup, distort the measured spectra in high flux pixelated multispectral detectors. These effects significantly reduce the detectors’ capabilities to be used for material identification, which requires accurate spectral measurements. We have developed a semi analytical computational algorithm for multispectral CdTe X-ray detectors which corrects the measured spectra for severe spectral distortions caused by the detector. The algorithm is developed for the Multix ME100 CdTe X-ray detector, but could potentially be adapted for any pixelated multispectral CdTe detector. The calibration of the algorithm is based on simple attenuation measurements of commercially available materials using standard laboratory sources, making the algorithm applicable in any X-ray setup. The validation of the algorithm has been done using experimental data acquired with both standard lab equipment and synchrotron radiation. The experiments show that the algorithm is fast, reliable even at X-ray flux up to 5 Mph/s/mm2, and greatly improves the accuracy of the measured X-ray spectra, making the algorithm very useful for both security and industrial applications where multispectral detectors are used.

This work seeks to develop an autonomous optimization of input computational resource parameters for arbitrary big-data computed tomography (CT) configurations. It is well known that graphics processing units (GPU) have been a boon to many high-performance applications, including CT. The reconstruction task has both colossal computational and data throughput requirements that easily tax high-end GPUs to their limit. For big-data industrial and research applications, the burden is exacerbated through the use of high pixel count detectors (≥ 16 megapixels) and the large number of projections needed to meet Nyquist sampling requirements, resulting in datasets up to terabytes in size. Previous work has shown that the GPU kernels can be optimized to efficiently handle big-data; however, as this work will show, some sensitivities exist with respect to the tunable input parameters that can exact an exaggerated toll on reconstruction performance. This work will investigate the input parameter space for various relevant and future-sized datasets and will present a calibration approach to optimize reconstruction performance for varying sized detectors, geometries, and graphics processing resources. This work has the potential to dramatically improve many non-destructive evaluation and inspection applications in industry, security, and research where reconstruction rate is the main bottleneck of the resource chain. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DEAC04-94AL85000.

To measure X-ray spectra with high count rates, we developed a detector consisting of a cerium-doped yttrium aluminum perovskite [YAP(Ce)] crystal and a recent multipixel photon counter (MPPC). Scintillation photons are detected using the MPPC, and the photocurrents flowing through the MPPC are converted into voltages and amplified using a high-speed current-voltage (I-V) amplifier. The MPPC bias voltage was set to a value at the pre-Geiger mode to perform zero-dark counting. The event-pulse widths were approximately 200 ns, and the widths were extend to approximately 1 μs. X-ray spectra were measured using a multichannel analyzer (MCA) for pulse-height analysis. The photon energy was roughly determined by the two-point calibration using tungsten K photons and iodine K fluorescence. Using the YAP(Ce)-MPPC detector, first-generation dual-energy computed tomography was accomplished using iodine and gadolinium contrast media.

Dedicated breast computed tomography (BCT) is an emerging clinical modality that can eliminate tissue superposition and has the potential for improved sensitivity and specificity for breast cancer detection and diagnosis. It is performed without physical compression of the breast. Most of the dedicated BCT systems use large-area detectors operating in cone-beam geometry and are referred to as cone-beam breast CT (CBBCT) systems. The large-area detectors in CBBCT systems are energy-integrating, indirect-type detectors employing a scintillator that converts x-ray photons to light, followed by detection of optical photons. A key consideration that determines the image quality achieved by such CBBCT systems is the choice of scintillator and its performance characteristics. In this work, a framework for analyzing the impact of the scintillator on CBBCT performance and its use for task-specific optimization of CBBCT imaging performance is described.

Powder-based flat panel X-ray scintillator screen has been widely used in many medical fields for diagnosis and measurement. For the proper application in medical field, high dose usage and high image quality are required. In this study, double-layer scintillator design is suggested for improving total efficiency with using theoretical x-ray absorption model and Mie-scattering-based Monte-Carlo (LightTools) analysis. Optimized scintillator layer design would be proposed with respect to the medical fields’ sufficient resolution-functionality.

We are building a dual-panel positron emission tomography (PET) system prototype that enables focused imaging of local regions of interest of the body with 1 mm3 spatial resolution, The detector panels are built from novel 3D position sensitive scintillation (3DPSS) detectors comprising arrays of 1x1x1 mm3 LYSO scintillation crystal elements coupled to position-sensitive avalanche photodiodes (PSAPD). At the present state of system construction, the measured energy resolution over 98,304 crystal elements coupled to 1,536 PSAPDs is 11.34%, and 76.2% (74,938) of the system LYSO crystal elements are found to have greater than 99% event positioning accuracy. Imaging studies performed with a high-resolution phantom demonstrate resolution of the smallest (1.2 mm diameter) features. Besides enabling 1 mm resolution clinical PET studies, we describe other novel ways we are planning to exploit the 3DPSS detector information.

iQID is an intensified quantum imaging detector developed in the Center for Gamma-Ray Imaging (CGRI). Originally called BazookaSPECT, iQID was designed for high-resolution gamma-ray imaging and preclinical gamma-ray single-photon emission computed tomography (SPECT). With the use of a columnar scintillator, an image intensifier and modern CCD/CMOS sensors, iQID cameras features outstanding intrinsic spatial resolution. In recent years, many advances have been achieved that greatly boost the performance of iQID, broadening its applications to cover nuclear and particle imaging for preclinical, clinical and homeland security settings. This paper presents an overview of the recent advances of iQID technology and its applications in preclinical and clinical scintigraphy, preclinical SPECT, particle imaging (alpha, neutron, beta, and fission fragment), and digital autoradiography.

We have proposed a novel edge-readout detector design for PET, which can easily provide sub-millimeter in-plane spatial resolution together with DOI information with resolution determined by the thickness of the crystal layers. Multiple factors that can potentially affect the coincidence resolving time (CRT) have been studied in this work. The result indicates there is a strong correlation between the coincidence resolving time and the parameters of a constant fraction discriminator (CFD), while the correlation between CRT and other factors such as inclusion of optical barriers, locations of gamma-ray interactions in the detector and light-coupling material’s refractive index (between crystal and SiPM’s silicon substrate) is weak. With optimum CFD parameters, a 200-ps CTR can be achieved.

Dual-modality Computed Tomography (CT)/X-ray Fluorescence Computed Tomography (XFCT) can be a valuable tool for imaging and quantifying the organ and tissue distribution of small concentrations of high atomic number materials in small-animal system. In this work, the framework for optimizing the micro-CT imaging system component of the dual-modality system is described, either when the micro-CT images are concurrently acquired with XFCT and using the x-ray spectral conditions for XFCT, or when the micro-CT images are acquired sequentially and independently of XFCT. This framework utilizes the cascaded systems analysis for task-specific determination of the detectability index using numerical observer models at a given radiation dose, where the radiation dose is determined using Monte Carlo simulations.

Conventional gamma cameras are heavy and occupy large volume for all required hardware components. Direct-conversion solid-state detectors like cadmium zinc telluride (CZT) enable a compact design of gamma cameras. In addition, conventional gamma cameras require different collimators for different gamma-ray photon energies, and the change of collimators between studies sometimes disrupts the workflow. To ease this inconvenience (i.e., bulkiness and collimator change), we have recently developed a compact, CZT-based, energy-independent gamma camera that requires only one collimator to cover a broad range of photon energies. In this paper, we show our design parameters and system specifications as well as simulation studies that support our design principles.

In the near-infrared-ray computed tomography (NIR-CT) scanner, NIR rays are produced from a light-emitting diode (LED) and detected using a phototransistor (PT) and an infrared filter. The LED-peak wavelength is 850 nm, and 850- nm-peak NIRs are detected using the filtrated PD. The photocurrents flowing through the PT are converted into voltages using an emitter-follower circuit, and the output voltages are sent to a personal computer through an analog-digital converter. The NIR projection curves for tomography are obtained by repeated translations and rotations of the object, and the translating is conducted in both directions of its movement. The 850-nm NIRs easily penetrated living bodies, and the NIR-CT was performed with changes in the sensitivity at relative sensitivities of 1 and 21.

The new generation positron emission tomography (PET) detectors for combined PET/magnetic resonance imaging (MRI) must achieve extremely good timing resolution while also being capable of simultaneous data acquisition in a high power, dynamic electromagnetic environment. SiPM-based detectors are a natural choice for this application, given the high gain and fast response of the SiPMs and their insensitivity to magnetic fields. We present the highly-integrated readout circuit “PETA”, specifically designed for SiPM readout and optimal timing resolution required for high performance TOF-PET. PETA is a bump-bonded chip, with pitch between bumps of 272 µm, suitable for compact detector design. It includes 36 readout channels, available with both single-ended and differential-ended front-ends. The event arrival time and energy are measured and digitized on chip with TDC/ADC circuits. The readout architecture is optimized for coping with high hit rate per channel. Two very compact MR-compatible TOF-PET detector modules based on PETA readout have been constructed and tested. Each is built on a single layer (ceramic and PCB substrate respectively), hosting the SiPM array and the readout electronics on opposite surfaces, and thermally decoupled with efficient integrated cooling. Coincidence measurements have shown coincidence time resolution of 230 ps FWHM using arrays of 2.25x2.25x10 mm3 LYSO crystals coupled to matching SiPMs.

Ultraviolet detection technology, as immediate area of research focus, has been adopted in the fields of fingerprint identification, corona detection and exhaust plume detection. Low-light CMOS, which can work in even 10^-3lux, is used in visible light channel. The prominent advantage of the dual-channel Ultraviolet/Low-light CMOS camera is the fusion of UV and wide dynamic range visible light information, which can enrich image details and help observers locate the UV targets in the complicated background around the clock rapidly. The paper studied on the component structure of UV ICMOS, imaging driving, the Ultraviolet/Low-light images fusion algorithm and the photon counting algorithm. The one-inch and wide dynamic range CMOS chip with the coupling optical fiber panel are coupled to the UV image intensifier. In consideration of the ultraviolet detection demand, the driving circuit of the CMOS chips is designed and the corresponding program based on Verilog language is written. After analysis and comparison of the characteristics of UV image and Low-light CMOS image, the improved Laplace pyramid fusion algorithm is applied. UV image and Low-light CMOS image are multiscale decompose, and the features in different frequency layer are chosen from either UV image or Low-light CMOS image. The connected components labeling way is utilized for the UV detection and imaging. At last, the detection experiments of the ultraviolet signal are carried out, and the results are given and analyzed.