In-line particle field holography at Pegasus Page: 3 of 8
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
IN-LINE PARTICLE FIELD HOLOGRAPHY AT PEGASUS
D.S. Sorenson, A. Obst, N.S.P. King, A J. Scannapieco, H. Lee, M. Sheppard, J. P. Roberts, D.
Platts, A.J. Taylor, S. Watson, M. P. Hockaday.
Los Alamos National Laboratory, Los Alamos, NM, 87544
B. Malone, C. Ciarcia, B. Frogget
EG&G/EM, Los Alamos, NM 87544
D. Westley, R. Flurer, P. Watts, K. Peterson, B. Pritchett, D. Malson, D. Crain
EG&G/EM, Las Vegas, NV, 89125
Abstract
An in-line holographic imaging system has been developed for hydrodynamic
experiments at the Pegasus facility located at Los Alamos National Laboratory. Holography
offers the unique capability to record distributions of particles over a three dimensional volume.
The system to be discussed is used to measure particle distributions of ejecta emitted after a
cylindrical aluminum liner (5.0 cm in diameter, 2.0 cm high) impacts a target (3.0 cm in
diameter). The ejecta emerges from the target traveling up to 7mm/ps and moves toward the
axial center of the system where the holographic imaging is performed. In-line holography is
particularly suited for the Pegasus pulsed power facility where the geometry restrictions make off
axis holography impractical. In order to record the fast moving particles a frequency-doubled
Nd:-YAG laser system has been implemented which produces a 80 ps 20 millijoule pulse at 532
nm. An optical relay system composed of a Fourier optical lens pair has been developed which is
placed 4.0 cm from the center of the region of interest. This relay lens pair forms an intermediate
image 32 cm from the object plane and the hologram is placed 4cm downstream of the
intermediate image. The holographic system and resolution capability will be discussed.
I. Introduction
When a strong shock wave reflects from a surface material can be emitted from the
surface (ejecta). The amount of material and size of material particulates vary depending on
many factors such as surface finish, and material type. This phenomena is not well understood.
Many studies have been done to measure the amount of mass emitted from a shocked surface".
Many of these measurements involve the use of a pick-up foil and Doppler Laser Interferometer
techniques to measure the velocity of the foil and inferring the amount of mass. Other techniques
to measure mass have involved using x-ray backlighters3, and time-dependent shadowgraphy.
However, these mass measurements were not able to return information on particle size. Particle
size information is critical in understanding how the particles propagate in gas. Currently, only a
few holographic measurements of ejecta have been made4. In this report a holographic technique
will be described which is being developed and applied to ejecta physics studies at the Pegasus
pulsed power facility at Los Alamos National Laboratory.II. Pegasus Pulsed Power Facility
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Sorenson, D.S.; Obst, A. & King, N.S.P. In-line particle field holography at Pegasus, article, September 1, 1995; New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc620151/m1/3/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.