The intensive developments of terawatt Ti:Sa lasers permit to extend laser-plasma interactions into the relativistic regime, providing very-short electron or proton bunches. Experimental researches developed at the interface of laser physics and radiation biology, using the combination of sub-picosecond electron beams in the energy range 2-15 MeV with femtosecond near-IR optical pulses might conjecture the real-time investigation of penetrating radiation effects. A perfect synchronization between the particle beam (pump) and optical beam at 820 nm (probe) allows subpicosecond time resolution. This emerging domain involves high-energy radiation femtochemistry (HERF) for which the early spatial energy deposition is decisive for the prediction of cellular and tissular radiation damages. With vacuum-focused intensities of 2.7 x 1019 W cm-2 and a high energy electron total charge of 2.5 nC, radiation events have been investigated in the temporal range 10-13 - 10-10s. The early radiation effects of secondary electron on biomolecular sensors may be investigated inside sub-micrometric ionisation, considering the radial direction of Gaussian electron bunches. It is shown that short range electron-biosensor interactions lower than 10 A take place in nascent track structures triggered by penetrating radiation bunches. The very high dose delivery 1013 Gy s-1 performed with laser plasma accelerator may challenge our understanding of nanodosimetry on the time scale of molecular target motions. High-quality ultrashort
penetrating radiation beams open promising opportunities for the development of spatio-temporal radiation biology, a crucial domain of cancer therapy, and would favor novating applications in nanomedicine such as highly-selective shortrange pro-drug activation.
Digital subtraction is useful for carrying out embossed radiography by shifting an x-ray source, and energy subtraction
is an important technique for imaging target region by deleting unnecessary region in vivo. X-ray generator had a
100-μm-focus tube, energy subtraction was performed at tube voltages of 40 and 60 kV, and a 3.0-mm-thick aluminum
filter was used to absorb low-photon-energy bremsstrahlung x-rays. Embossed radiography was achieved with cohesion
imaging using a flat panel detector (FPD) with pixel sizes of 48×48 μm, and the shifting distance of the x-ray source in
horizontal direction and the distance between the x-ray source and the FPD face were 5.0 mm and 1.0 m, respectively.
At a tube voltage of 60 kV and a tube current of 0.50 mA, x-ray intensities without filtering and with filtering were 307
and 28.4 μGy/s, respectively, at 1.0 m from the source. In embossed radiography of non-living animals, the spatial
resolution measured using a lead test chart was approximately 70 μm, and we observed embossed images of fine bones,
soft tissues, and coronary arteries of approximately 100 μm.
Stereo, multi-perspective, and volumetric display technologies have made several recent gains. We are seeing increased
availability of such systems for entertainment, both in theaters and for the home. The concurrent advent of medical
imaging modalities that deliver very large data sets such as, spiral CT, high-field MRI, and 3-D ultrasound, makes
renewed assessment of 3-D display of medical images attractive. We concentrate on autostereographic displays, those
that are viewed without viewing aids such as special eye-glasses or goggles.
We begin with a very brief review of a few stereo-display, multi-perspective, and volumetric display technologies. We
focus our attention primarily on the integral display (ID) and the computer-generated hologram (CGH). We will examine
the boost that ID has gotten from the availability of flat-panel displays with very high pixel counts. We also discuss
some recent advances in CGH's included the emergence of rewritable holographic materials.
We also look at one, undeveloped 3-D display technology: the Correlelogram.
X-Ray Fluorescence (XRF) analysis is useful for measuring density distributions of contrast media in vivo. An XRF
camera was developed to carry out mapping for iodine-based contrast media used in medical angiography. In this
camera, objects are exposed by an x-ray beam formed using a 3.0-mm-diameter lead hole. Next, cerium K-series
characteristic x-rays are absorbed effectively by iodine media in objects, and iodine fluorescences are produced from
the objects. Iodine Kα fluorescences are selected out using a 58-μm-thick stannum filter and are detected by a cadmium
telluride (CdTe) detector. Kα rays are discriminated out by a multichannel analyzer (MCA), and photon number is
counted by a counter board (CB). The objects are moved and scanned using an x-y stage driven by a two-stage
controller, and x-ray images obtained by iodine mapping are shown in a personal computer (PC) monitor. In particular,
iodine fluorescences were produced from remanent iodine elements in a cancer region of a rabbit ear.
This paper reports the design trade off study of the design of an innovative CMOS active pixel sensor (CAPS) based on Silicon-on-Insulator (SOI) technology. The CAPS designs approach provides the flexibility and high-density features of hybrid pixel sensors with photon counting architecture. This sensor is the key component for optimized X-ray Tomosynthesis. A proof-ofprinciple test chip, paying particular attention to the noise performance of the pixel, front-end electronics (FEE) and readout speed, is available for testing in 2008. We present the design of the test chip in this paper.
An x-ray fluorescence (XRF) computed tomography (CT) system utilizing a cadmium telluride (CdTe) detector is
described. The CT system is of the first generation type and consists of a cerium x-ray generator, a turn table, a
translation stage, a two-stage controller, a CdTe spectrometer, a multichannel analyzer (MCA), a counter board (CB),
and a personal computer (PC). When an object is exposed by the x-ray generator, iodine K-series fluorescences are
produced and are detected from vertical direction to x-ray axis using the spectrometer. Fluorescent photons are selected
out using the MCA and are counted by the PC via CB, and XRF CT is performed by repeating translation and rotation
of an object.
An energy-discriminating K-edge x-ray Computed Tomography (CT) system is useful for increasing contrast resolution
of a target region and for diagnosing cancers utilizing a drug delivery system. The CT system is of the first generation
type and consists of an x-ray generator, a turn table, a translation stage, a two-stage controller, a cadmium telluride
(CdTe) detector, a charge amplifier, a shaping amplifier, a multi-channel analyzer (MCA), a counter board (CB), and a
personal computer (PC). The K-edge CT is accomplished by repeating translation and rotation of an object. Penetrating
x-ray spectra from the object are measured by a spectrometer utilizing the CdTe detector, amplifiers, and MCA. Both
the photon energy and the energy width are selected by the MCA for discriminating photon energy. Enhanced iodine
K-edge x-ray CT was performed by selecting photons with energies just beyond iodine K-edge energy of 33.2 keV.
We report on the development of a practical, easy-to-use, multi-element, solid-state instrument for detecting and imaging
tritium contamination on surfaces. The innovation, which enables this instrumentation, relies on cutting-edge silicon
avalanche photodiode (APD) array detector technology to provide an effective coverage area without compromising the
overall sensitivity. We discuss the design and assembly of a prototype unit to monitor a surface area of over 900 mm2
while maintaining a spatial resolution of less than 4 mm. During tests at Los Alamos National Laboratories, we
demonstrated tritium counting efficiencies of over 40% and established that this unit can be used to expedite established
testing procedures by locating areas of potential activity or when combined with established swipe analysis.
CMOS solid-state photomultipliers (CMOS-SSPM) are new, potentially very inexpensive, photodetectors that have
the promise of supplanting photomultiplier tubes and standard photodiodes for many nuclear radiation detection
measurements using scintillator crystals. The compact size and very high gain make SSPMs attractive for use in
applications where photomultiplier tubes cannot be used and standard photodiodes have insufficient sensitivity. In this
effort, the use of SSPMs was investigated for the detection of neutrons with the goal of designing a detector for portable
systems that has the capability of discriminating neutrons from gamma rays.
The neutron scintillation signatures were measured using boron-loaded plastic scintillators. Our detector concept
design incorporates a dual-scintillator design with both a neutrons sensitive organic scintillator (a boron-loaded gel) and
a gamma ray sensitive inorganic scintillator (LYSO). Using this design, the gamma ray signal is suppressed and the
neutron events are clearly resolved. The design was modeled to optimize the detection efficiency for both thermal and
energetic neutrons. In addition, the detection of thermal neutrons in the presence of gamma rays was examined using the
SSPM coupled to Cs2LiYCl6:Ce scintillator (CLYC).
Isotopic neutron sources have been available for more than six decades. At the Atomic Institute in Vienna, operating a 250 kW TRIGA reactor, different neutron sources are in use for instrument calibration and fast neutron applications but we have only little information about their construction and densities. The knowledge of source design is essential for a complete MCNP5 modeling of the experiments. Neutron radiography (NR) and neutron tomography (NT) are the best choices for the non-destructive inspection of the source geometry and homogeneity. From the transmission analysis we gain information about the shielding components and the densities of the radio-isotopes in the cores. Three neutron sources, based on (alpha, n) reaction, have been investigated, two 239PuBe sources and one 241AmBe source. In the NR images the internal structure was clearly revealed using high-resolving scintillation and imaging plate detectors. In one source tablet a crack was detected which causes asymmetric neutron emission. The tomography inspection of strong absorbing materials is more challenging due to the low beam intensity of 1.3x105 n/cm2s at our NT instrument, and due to the beam hardening effect which requires an extension of reconstruction software. The tomographic inspection of a PuBe neutron source and appropriate measures for background and beam hardening correction are presented.
A novel detection technique employing x-ray diffraction (XRD) to screen for Special Nuclear Materials (SNMs),
in particular for uranium, is presented. It is based on the interesting fact that uranium (and incidentally,
plutonium) has a non-cubic lattice structure, in contrast to all other non-SNM, high-density elements of the
Following a brief review of the cubic crystal structures exhibited by high atomic number species such as lead,
the departure from cubicity exhibited by room-temperature uranium (orthorhombic) is discussed and its effect on
the uranium XRD pattern is examined. The XRD lines of uranium are compared with those of lead, a common
high-Z material found in container traffic. Significant differences are evident arising from their different crystal
In order to achieve adequate penetration, both of suspicious high-Z materials and their containers, high photon
energies must be used. Physical and technological considerations relevant to performing XRD at 1 MeV are discussed and a novel secondary aperture scheme permitting high-energy XRD is presented. It is concluded that the importance of the application and the prospect of its feasibility are sufficient to warrant experimental verification.
Characteristic x-ray generator consists of a constant high-voltage power supply, a filament power supply, a
turbomolecular pump, and an x-ray tube. The x-ray tube is a demountable diode which is connected to the
turbomolecular pump and consists of the following major devices: a pipe-shaped molybdenum hole target, a tungsten
hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate x-ray window 0.25 mm in
thickness, and a stainless-steel tube body. In the x-ray tube, the positive high voltage is applied to the anode (target)
electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied
was from 25 to 35 kV, and the tube current was regulated to within 10 μA by the filament temperature. The exposure
time is controlled in order to obtain optimum x-ray intensity. The electron beams from the cathode are converged to the
target by the focusing electrode, and sharp K-series characteristic x-rays are produced through the focusing electrode at
a tube voltage of 35 kV. Using this generator, we performed monochromatic radiography, monochromatic x-ray
computed tomography, and x-ray fluorescence analysis.