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Los Alamos Proton Radiography Facility

Established	1995
Field of research	Subatomic physics
Location	Los Alamos, New Mexico
Affiliations	Los Alamos National Laboratory
Website	[1]

Proton radiography, invented at Los Alamos National Laboratory, employs a high-energy proton beam to image the properties and behavior of materials driven by high explosives.

History

Proton radiography was developed at the Los Alamos National Laboratory in 1995.

To read further on about the facts leading up to the development: http://www.eurekalert.org/features/doe/2003-05/danl-pra051303.php

Features of Proton Radiography

The high energy of the beam gives proton radiography a penetrating power sufficient to see fine internal details in objects of a wide variety of densities, such as lead, plutonium, uranium, or high explosives -- shedding light on features under extreme conditions that are difficult to discern with x-ray imaging.

A hemisphere of high explosives is placed inside a hollow hemisphere of a uranium alloy and radiographed to study the failure mechanisms of U₆Nb.

The penetrating power of protons makes possible detailed radiographic images of experiments conducted in sealed metal containment vessels, to study damage features in explosively shocked samples. The sealed vessel provides the safety envelope to study samples of hazardous materials such as beryllium and plutonium.

Also, since the proton beam is composed of charged particles, the beam may be focused with magnetic lenses to form images of the object far away from the interaction region for several great advantages. For example, it is possible to enhance the signal from selected materials.

Additionally, using the proton beam from a particle accelerator allows for multiple images taken at a wide range of intervals, capturing a movie of the event where the frames may be spaced from one second to 10-7 seconds apart.

Finally, proton radiography makes possible quantitative measurements of material densities under extreme conditions, providing a diagnostic capable of predicting the performance of untested weapons' components or aged components in the stockpile. This precision allows for a range of fundamental science measurements as well.

Proton Radiography Facilities

pRad at Los Alamos National Laboratory

The Proton Radiography Facility (pRad) at the Los Alamos Neutron Science Center uses 800 MeV protons provided by the LANSCE accelerator facility to investigate dynamic experiments in support of national and international weapons science and stockpile stewardship programs.

The invention of imaging proton radiography at Los Alamos is the direct result of the synergy between defense-mission and basic-science researchers at Los Alamos. The penetrating power of high energy protons, like that of x-rays, makes them an excellent probe of a wide range of materials. But the incredible efficacy and versatility of pRad stems from the ability to produce multiple proton pulses in an accelerator and use magnets to manipulate the proton beam.

The beam for pRad is provided by the Los Alamos Neutron Science Center (LANSCE). The LANSCE accelerator team meets the specific needs of each experiment by providing a wide range timing sequences for the proton pulses in the beam. Each proton pulse results in one radiographic image; a series of images make a movie.

Proton radiography and a similar technique with electron radiography are slated to play an integral role in MaRIE (Matter-Radiation Interactions in Extremes), the Laboratory’s planned experimental facility, which will utilize charged particle radiography to diagnose material properties in dynamic conditions.

In addition to explosive experiments in containment vessels, the pRad team conducts experiments with a powdergun to slam a flyer plate into a target. One series of experiments with the pRad powdergun demonstrates the ability to observe the flyer impact and measure the particle and shock wave velocities in the materials. Most importantly, these experiments have provided direct density measurements of shocked metals with very high accuracy (<1%) and these data have been used to validate existing Equations of State for the materials studied.

Russian Federal Nuclear Center

(proposed) European Union

External links

• http://lansce.lanl.gov/pRad/index.shtml
• http://www.lanl.gov/quarterly/q_w03/pro_rad.shtml

Category:Los Alamos National Laboratory Category:Los Alamos Neutron Science Center Category:Buildings and structures in Los Alamos County, New Mexico