Fesseha Mariam
YOU?
Author Swipe
View article: A profile monitor for proton radiography experiments at the Los Alamos Neutron Science Center
A profile monitor for proton radiography experiments at the Los Alamos Neutron Science Center Open
The Proton Radiography (pRad) facility at the Los Alamos Neutron Science Center utilizes pulses of protons delivered by the 800 MeV linear accelerator to produce a series of radiographic images to study the dynamic behavior of materials un…
View article: Design and commissioning of the PRIOR-II “proton microscope for FAIR”
Design and commissioning of the PRIOR-II “proton microscope for FAIR” Open
A new high energy proton radiography facility PRIOR-II (Proton Microscope for FAIR) has been designed, constructed, and successfully commissioned at the GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany) pushing the technic…
View article: Search for rare muon and pion decay modes with the Crystal Box detector
Search for rare muon and pion decay modes with the Crystal Box detector Open
New experimental upper limits for the branching ratios of the lepton-family-number nonconserving decays ..mu../sup +/ ..-->.. e/sup +/..gamma.. and ..mu../sup +/ ..-->.. e/sup +/..gamma gamma.. are presented. A new determination of ..gamma…
View article: In-situ Monitoring of Dynamic Phenomena during Solidification and Phase Transformation Processing
In-situ Monitoring of Dynamic Phenomena during Solidification and Phase Transformation Processing Open
The purpose of this project is to: (1) Directly observe phase transformations and microstructure evolution using proton (and synchrotron x-ray) radiography and tomography; (2) Constrain phase-field models for microstructure evolution; (3) …
View article: A class of ejecta transport test problems
A class of ejecta transport test problems Open
Hydro code implementations of ejecta dynamics at shocked interfaces presume a source distribution function ofparticulate masses and velocities, f{sub 0}(m, v;t). Some of the properties of this source distribution function have been determi…
View article: Active interrogation using energetic protons
Active interrogation using energetic protons Open
Energetic proton beams provide an attractive alternative when compared to electromagnetic and neutron beams for active interrogation of nuclear threats because they have large fission cross sections, long mean free paths and high penetrati…
View article: Proton microscopy at GSI and FAIR
Proton microscopy at GSI and FAIR Open
Proton radiography was invented in the 1990's at Los Alamos National Laboratory (LANL) as a diagnostic to study dynamic material properties under extreme pressures, strain and strain rate. Since this time hundreds of dynamic proton radiogr…
View article: Calibration and optimization of proportional counter modules using Garfield
Calibration and optimization of proportional counter modules using Garfield Open
Prototypes of radiation detector arrays used for charged-particle radiography require iniliol calibration to correlate the distribution of electron arrival time to the particle track locations. This step is crucial to obtaining the spatial…
View article: Contrast-enhanced proton radiographic sensitivity limits for tumor detection
Contrast-enhanced proton radiographic sensitivity limits for tumor detection Open
Purpose: Proton radiography may guide proton therapy cancer treatments with beam's-eye-view anatomical images and a proton-based estimation of proton stopping power. However, without contrast enhancement, proton radiography will not be abl…
View article: Experimental observations of exploding bridgewire detonator function
Experimental observations of exploding bridgewire detonator function Open
Exploding bridgewire detonators are an industry standard technology used for over 75 years and valued for their precise timing and safety characteristics. Despite widespread use, their functional mechanism remains controversial with both s…
View article: Dark field proton radiography
Dark field proton radiography Open
A pre- and post-collimation scheme has been applied to high energy proton radiography to establish a dark field condition, which defaults to a state of no transmission until a scatterer is placed at the object plane. This technique, dark f…
View article: Compaction model validation under non-planar shock wave loading conditions
Compaction model validation under non-planar shock wave loading conditions Open
Three continuum compaction models are calibrated to planar impact data for CeO2 powder and used to predict the shock compaction behavior of CeO2 powder under cylindrically converging shock wave loading. All experiments and computations are…
View article: Demonstration of transmission high energy electron microscopy
Demonstration of transmission high energy electron microscopy Open
Charged particle radiography with 800 MeV protons has been used for decades at LANL and developed around the world to study dynamic material properties. Recently, charged particle radiography has been demonstrated with the use of high-ener…
View article: MHD Modeling of Shock Physics Experiments with the Phelix Portable High Magnetic Field Drive
MHD Modeling of Shock Physics Experiments with the Phelix Portable High Magnetic Field Drive Open
The PHELIX portable pulsed power driver has recently completed a set of experiments examining the response of granular material to convergent shock loading. Here a nearly 4 MA peak current is delivered to a Z-pinch load with a quarter wave…
View article: Demonstration of transmission high energy electron microscopy
Demonstration of transmission high energy electron microscopy Open
High energy electrons have been used to investigate an extension of transmission electron microscopy. This technique, transmission high energy electron microscopy (THEEM), provides two additional capabilities to electron microscopy. First,…
View article: The spikes from Richtmyer-Meshkov instabilities in pulsed power cylindrical experiments
The spikes from Richtmyer-Meshkov instabilities in pulsed power cylindrical experiments Open
The LANL PHELIX pulsed-power driven liner implosion apparatus is fielded to measure the growth of Richtmyer-Meshkov instabilities (RMIs) in a cylindrical geometry under the conditions of liquid (Cren-1), mixed-state (Cren-2), and solid (Cr…
View article: PHELIX Crenulation 2 and 3 Flash Report
PHELIX Crenulation 2 and 3 Flash Report Open
This report documents the execution of the PHELIX driven Crenulation 2 and 3 at LANSCE proton radiography experiments in FY17 in support of the LANL Science Campaign-1 L2 Milestone (#5721). It should be noted that LANL Science Campaign 3 a…
View article: Multi-GeV electron radiography for measurements of fast dynamic systems
Multi-GeV electron radiography for measurements of fast dynamic systems Open
Charged particle radiography has been developed in the past decade to provide high-resolution, muti-frame flash radiography of dynamic systems. This development has focused on proton radiography utilizing 11 MeV to 50 GeV protons for a wid…
View article: Inverse-collimated proton radiography for imaging thin materials
Inverse-collimated proton radiography for imaging thin materials Open
Relativistic, magnetically focused proton radiography was invented at Los Alamos National Laboratory using the 800 MeV LANSCE beam and is inherently well-suited to imaging dense objects, at areal densities >20 g cm−2. However, if the un…
View article: Commissioning of the PRIOR proton microscope
Commissioning of the PRIOR proton microscope Open
Recently, a new high energy proton microscopy facility PRIOR (Proton Microscope for FAIR Facility for Anti-proton and Ion Research) has been designed, constructed, and successfully commissioned at GSI Helmholtzzentrum für Schwerionenforsch…
View article: High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV
High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV Open
Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantita…