LOS ALAMOS NATIONAL LABORATORY
KEY FACILITIES
Dual Axis Radiographic Hydrodynamic Test Facility
The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) facility, located at TA-15, Area III, is a dual-axis enhanced-radiography hydrodynamic test facility, designed to facilitate the LANL's support of the Stockpile Stewardship Program, to accurately and effectively assessing the continued safety, performance, and reliability of aging nuclear weapons. Area III of TA-15 has been dedicated to high explosives testing for over 50 years. The Pulsed High-Energy Radiation Machine Emitting X-Rays (PHERMEX) site (11 acres) and the DARHT site (8 acres) are about 2,000 feet apart by straight line distance and 1.2 miles apart by road. DOE designed DARHT to essentially replace PHERMEX and to provide enhanced diagnostic capability to study the behavior of nuclear weapons. The plan was for DOE to phase out operation of PHERMEX approximately four years after the DARHT facility became operational and to use the existing Radiographic Support Laboratory (RSL), which had supported all radiographic machines at TA-15, to support the DARHT facility.
DARHT is a high-explosive firing site equipped with two massive flash X-ray machines designed to provide valuable freeze-frame, high-resolution radiographic photos of materials imploding at speeds over 10,000 miles an hour. These time-resolved, stereoscopic images can then be used to provide three-dimensional information. DARHT enables imaging through very thick, dense materials and takes multiple, very brief snapshots from two different lines of sight (within millionths of a second). DARHT consists of two electron accelerators positioned at a 90-degree angle, each focused on a single firing point. At that target, the DARHT beams produce high-energy X-rays to image the behavior of materials in nuclear weapon mock-ups under extreme conditions. The facility's walls are made of specially reinforced concrete and are more than five feet thick in the area facing the high-explosives test.
DARHT's first axis, the world's most advanced hydrodynamic test facility, performed its first hydrodynamic test in November 1999, marking its operational readiness. It began providing radiographic data to NNSA's stockpile stewardship program in the fall of 2000. Both LLNL and LANL have made use of DARHT for hydrodynamic experiments since its first axis was completed in 2000. In May of 2007 the experiments moved into fully contained in steel vessels.
The second axis (DARHT) was set to be completed in 2002. The second-axis injector was demonstrated on July 2, 2002. The second-axis accelerator was demonstrated on December 21, 2002. The second-axis camera system was delivered on February 6, 2003. On March 26, 2003, construction of DARHT's second axis was completed. In January 2008, the DARHT facility was authorized by the National Nuclear Security Administration (NNSA) to begin full power operations of Axis 2. Each Axis 2 cell is a 15,000-pound doughnut-shaped aluminum structure with an internal configuration of magnetic material and insulating oil. At the center of each cell is a high-voltage, vacuum-insulated beamline. Electronic detectors turn the X-rays into high-speed digital images. Axis 2 consists of 74 individual accelerator cells. The second axis creates a 17-million-volt electron beam in four X-ray pulses, together lasting for 1.5 millionths of second. The data from the four frames of X-ray images, allows the creation of the first-ever three-dimensional images. In addition to the hydrodynamic testing for experimental confirmation of weapons computer codes, DARHT also has the capabilities for shock physics, high-velocity impact, and material and high-explosives experiments.
The budget for the first phase of DARHT was about $105.7 million. In 1999, the second phase was estimated at $154 million. It was completed within its budget of $155 million. The total project was completed within the overall capital construction budget of $260 million.
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