We have developed a new method for the fast inversion of borehole resistivity measurements acquired in multiple wells using logging-while-drilling instruments. There are two key novel contributions. First, we approximate general 3D transversely isotropic (TI) formations with a sequence of several “stitched” 1D planarly layered TI sections. This allows us to approximate the solution of rather complex 3D formations using only 1.5D simulations. Second, the developed method supports the simultaneous inversion of measurements acquired in different neighboring wells and/or with different logging instruments. Numerical experiments performed with realistic 3D synthetic formations confirm the flexibility of the method and the reliability of the inversion products. The method yields relative errors of less than 5% on the model space, and it enables the interpretation of resistivity measurements acquired in multiple wells (e.g., an exploratory, an offset, and a geosteering well) and with any combination of coaxial and/or triaxial commercial logging measurements acquired with known antennae configurations. Numerical results also indicate that thinly bedded resistive formations are very sensitive to the presence of noise on the measurements and/or to possible errors on bed-boundary locations, whereas conductive layers are only weakly sensitive to those effects.

We introduce a multi-domain decomposition Fourier finite element (MDDFFE) method for the simulation of three-dimensional (3D) marine controlled source electromagnetic measurement (CSEM). The method combines a 2D finite element (FE) method in two spatial dimensions with a hybrid discretization based on a Fourier FE method along the third dimension. The method employs a secondary field formulation rather than the total field formulation. We apply the MDDFFE method to several synthetic marine CSEM examples exhibiting bathymetry and/or multiple 3D subdomains. Numerical results show that the use of the MDDFFE method reduces the problem size by as much as 87 % in terms of the number of unknowns, without any sacrifice in accuracy.

The beta-amyloid (Aβ) peptide was used as an important biomarker for Alzheimer's disease (AD) diagnosis. The development of an accurate, selective, rapid, and highly sensitive technique for detecting of Aβ level is an important issue in biology, and medicine to assess human health risks. Here, gold nanoparticles (Au NPs) with different size were electrochemically deposited onto the indium tin oxide (ITO) substrate in the presence of different molecular weights of surfactants. The modified substrates were used as a high sensitive electrochemical sensor of in-vitro as well as ex-vivo monitoring of Aβ based on cyclic voltammetry and square wave voltammetry techniques. Our findings revealed that the modification of ITO electrode with Au NPs could enhance its sensor performance with high sensitivity for low concentration levels of Aβ over a wide linear range with a detection limit of about 20.7 ng/g, which is less than the concentration of insoluble Aβ40 (105.4±40.2 μg/g) in brain of AD induced. In addition, Au NPs/ITO modified electrodes have demonstrated ability to monitor Aβ in the brain extracted samples without any potential interference with other components. Raman spectroscopy has been used to confirm the presence of Aβ in the AD-induced samples. Thus, it is applicable for analyzing ex-vivo samples.

The beta-amyloid (Aβ) peptide was used as an important biomarker for Alzheimer's disease (AD) diagnosis. The development of an accurate, selective, rapid, and highly sensitive technique for detecting of Aβ level is an important issue in biology, and medicine to assess human health risks. Here, gold nanoparticles (Au NPs) with different size were electrochemically deposited onto the indium tin oxide (ITO) substrate in the presence of different molecular weights of surfactants. The modified substrates were used as a high sensitive electrochemical sensor of in-vitro as well as ex-vivo monitoring of Aβ based on cyclic voltammetry and square wave voltammetry techniques. Our findings revealed that the modification of ITO electrode with Au NPs could enhance its sensor performance with high sensitivity for low concentration levels of Aβ over a wide linear range with a detection limit of about 20.7 ng/g, which is less than the concentration of insoluble Aβ40 (105.4±40.2 μg/g) in brain of AD induced. In addition, Au NPs/ITO modified electrodes have demonstrated ability to monitor Aβ in the brain extracted samples without any potential interference with other components. Raman spectroscopy has been used to confirm the presence of Aβ in the AD-induced samples. Thus, it is applicable for analyzing ex-vivo samples.

The beta-amyloid (Aβ) peptide was used as an important biomarker for Alzheimer's disease (AD) diagnosis. The development of an accurate, selective, rapid, and highly sensitive technique for detecting of Aβ level is an important issue in biology, and medicine to assess human health risks. Here, gold nanoparticles (Au NPs) with different size were electrochemically deposited onto the indium tin oxide (ITO) substrate in the presence of different molecular weights of surfactants. The modified substrates were used as a high sensitive electrochemical sensor of in-vitro as well as ex-vivo monitoring of Aβ based on cyclic voltammetry and square wave voltammetry techniques. Our findings revealed that the modification of ITO electrode with Au NPs could enhance its sensor performance with high sensitivity for low concentration levels of Aβ over a wide linear range with a detection limit of about 20.7 ng/g, which is less than the concentration of insoluble Aβ40 (105.4±40.2 μg/g) in brain of AD induced. In addition, Au NPs/ITO modified electrodes have demonstrated ability to monitor Aβ in the brain extracted samples without any potential interference with other components. Raman spectroscopy has been used to confirm the presence of Aβ in the AD-induced samples. Thus, it is applicable for analyzing ex-vivo samples.

Future development and applications of accelerators and electron devices in the fields of free electron lasers (FELs), high-frequency vacuum electronics, high-power microwave devices, and electron beam lithography are partially restricted due to the electron source brightness. A high brightness electron gun with small emittance and high average beam current is one of the key goals in current technological developments. RF electron guns have the ability to reduce emittance growth due to the space-charge effects. Among RF guns, thermionic guns are quite attractive because of their simple configuration with no high voltage stage or complicated laser systems. In addition, the high acceleration reached in the gun cavity (up to 100 MV/m) can easily compress the bunch lengths to have sufficient peak current for FEL driving. On the other hand, Back Bombardment (BB) effect limits the wide usage of Thermionic RF guns worldwide. In this book, BB phenomena, associated effects and method of mitigations are presented. Numerical Model for simulating the effect of back bombardment in thermionic RF gun is used to discus the phenomeno

In order to fight against the global nuclear terrorism, interrogation of special nuclear materials (SNMs), such as U-235 and Pu-239, is receiving high attention. The passive detection systems are inadequate, however, several active detection systems have been proposed for U-235 detection in seaports and airports. Those systems, however, require highly intense sources and/or heavy shielding materials surrounding the detectors for blocking the background neutrons and/or gamma-rays. We are developing the world’s first “portable” interrogation system, comprising a compact and lightweight D-D Inertial Electrostatic Confinement (IEC) fusion neutron source [1-2] coupled with Tensioned Metastable Fluid Detector (TMFD) technology [3]. The major obstacle facing the neutron-based active interrogation systems is to identify the secondary neutrons that indicate the existence of SNMs from the probing neutrons. To overcome this obstacle, our team have recently developed an advanced neutron-in neutron-out technique, the Threshold Energy Neutron Analysis (TENA) technique [4]. In this technique, mono-energetic neutrons from D-D fusion, 2.45 MeV, used as probing neutrons, while the secondary neutrons above 2.45 MeV, from SNMs, are detected using TMFD. The TMFD has been showed capability to reject the 2.45 MeV probing D-D neutrons and all background gamma-rays. Experiments have been carried out to show the ability to detect 10 g of HEU by use of a DD-IEC neutron source, and TMFD. The conditions and experimental results will be presented with the extremely compact and intense D-D IEC neutron source developed for this purpose (25 cm in diameter, 30 kg, >5e7 n/sec).

The first portable active interrogation system for special nuclear materials (SNM), such as U-235 and Pu-239, is being developed by our group. The system employs an inertial electrostatic confinement (IEC) device as a neutron source. The first prototype of the IEC device, with 17 cm chamber diameter (IEC17), has been fabricated, assembled and is being tested. Preliminary results from the first portable chamber will be presented in this paper.

The matching of a particle beam to specific transverse parameters, imposed by various operational, functional and diagnostic reasons, is an essential procedure in most types of accelerators. While well-established methods can easily match beams of negligible self fields, their accuracy is significantly reduced in the presence of strong space-charge forces. In a pursuit of time-efficient matching solutions for space-charge influenced beams, two approaches are demonstrated in this paper: a faster and more approximative one for symmetric beam transport along periodic and dense lattices, and a more analytic one for broader beam and lattice conditions. Beam dynamics simulations and experimental measurements are used to validate the performance of the suggested methods for the matching requirements of the transverse phase–space tomography at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ).

This work discusses the behavior of electron bunch charge produced in an L-band normal conducting radio frequency gun from Cs2Te photocathodes illuminated with ps-long UV laser pulses and presumed homogeneous flattop laser transverse distribution. The measured charge shows the expected linear dependence in the quantum efficiency limited emission regime at low laser pulse energies. At higher laser pulse energy, the measured charge in the space charge limited emission regime should saturate, assuming an ideal homogeneous flattop laser transverse distribution. However, this behavior is not observed experimentally. Instead of saturating, the measured charge continues to increase with laser pulse energy, albeit with much weaker dependence than in the quantum efficiency limited emission regime. Simulations with the space charge particle tracking code ASTRA show that the charge saturates as expected using a homogeneous flattop laser transverse distribution. The discrepancy between simulations and measured excess charge may be attributed to the presence of unintentional Gaussian-like decaying radial halo beyond the core of the otherwise presumed homogeneous flattop core. The rate of increase of the measured charge at high laser pulse energies seems to be proportional to the amount of halo despite charge saturation in the core of the transverse laser radial profile. By utilizing core + halo particle distributions based on measured radial laser profiles, ASTRA simulations and semi-analytical emission models reproduce the behavior of the measured charge for a wide range of RF gun and laser operational parameters within the measurement uncertainties.