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59-510: Planning for DARHT began in the early 1980s. Based upon the success of Livermore's FXR, induction-linac facility, in 1987 Los Alamos chose the same type of accelerator to replace PHERMEX, an RF accelerator commissioned in 1963. The project became an important priority after the United States stopped testing nuclear weapons in 1992. Approval for an overhaul and new axis came in stages, with the first axis approved for construction in 1992 and

118-565: A draft environmental impact statement (DEIS) or draft environmental impact report (DEIR). The purpose of the NEPA is to promote informed decision-making by federal agencies by making "detailed information concerning significant environmental impacts" available to both agency leaders and the public. The NEPA was the first piece of legislation that created a comprehensive method to assess potential and existing environmental risks at once. It also encourages communication and cooperation between all

177-455: A positron , each with a mass of 0.511 MeV/ c , can annihilate to yield 1.022 MeV of energy. A proton has a mass of 0.938 GeV/ c . In general, the masses of all hadrons are of the order of 1 GeV/ c , which makes the GeV/ c a convenient unit of mass for particle physics: The atomic mass constant ( m u ), one twelfth of the mass a carbon-12 atom, is close to

236-469: A full-scale EIS. Most EAs result in a FONSI. A limited number of federal actions may avoid the EA and EIS requirements under NEPA if they meet the criteria for a categorical exclusion (CATEX). A CATEX is usually permitted when a course of action is identical or very similar to a past course of action and the impacts on the environment from the previous action can be assumed for the proposed action, or for building

295-554: A half tons. Four cores fit into each induction cell. Perhaps the most significant technical advance achieved at the DARHT facility are the high-speed cameras used to image x-rays on the second axis. These cameras utilizes the world's largest LSO crystal array to convert the x-rays into visible light which are then imaged with the world's highest speed CCDs (developed jointly by MIT and Los Alamos) at more than two million frames per second. These scintillation cameras are further augmented by

354-509: A large anti-scatter (“Bucky”) grid to improve image contrast. The unique combination of diagnostics solves technical surveillance problems that have persisted since the Manhattan Project enabling the United States to assert higher confidence in its nuclear stockpile performance and safety margins without the need for nuclear testing. [REDACTED]  This article incorporates public domain material from websites or documents of

413-491: A photon are related by E = h ν = h c λ = 4.135   667   696 × 10 − 15 e V / H z × 299 792 458 m / s λ {\displaystyle E=h\nu ={\frac {hc}{\lambda }}={\frac {\mathrm {4.135\ 667\ 696\times 10^{-15}\;eV/Hz} \times \mathrm {299\,792\,458\;m/s} }{\lambda }}} where h

472-454: A single electron accelerating through an electric potential difference of one volt in vacuum . When used as a unit of energy , the numerical value of 1 eV in joules (symbol J) is equal to the numerical value of the charge of an electron in coulombs (symbol C). Under the 2019 revision of the SI , this sets 1 eV equal to the exact value 1.602 176 634 × 10  J . Historically,

531-479: A structure within the footprint of an existing, larger facility or complex. For example, two recently completed sections of Interstate 69 in Kentucky were granted a CATEX from NEPA requirements as these portions of I-69 utilize existing freeways that required little more than minor spot improvements and a change of highway signage. Additionally, a CATEX can be issued during an emergency when time does not permit

590-413: A system of natural units in which the speed of light in vacuum c and the reduced Planck constant ħ are dimensionless and equal to unity is widely used: c = ħ = 1 . In these units, both distances and times are expressed in inverse energy units (while energy and mass are expressed in the same units, see mass–energy equivalence ). In particular, particle scattering lengths are often presented using

649-686: A unit of inverse particle mass. Outside this system of units, the conversion factors between electronvolt, second, and nanometer are the following: ℏ = 1.054   571   817   646 × 10 − 34   J ⋅ s = 6.582   119   569   509 × 10 − 16   e V ⋅ s . {\displaystyle \hbar =1.054\ 571\ 817\ 646\times 10^{-34}\ \mathrm {J{\cdot }s} =6.582\ 119\ 569\ 509\times 10^{-16}\ \mathrm {eV{\cdot }s} .} The above relations also allow expressing

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708-443: A value of one volt , which is 1 J/C , multiplied by the elementary charge e  =  1.602 176 634 × 10  C . Therefore, one electronvolt is equal to 1.602 176 634 × 10  J . The electronvolt (eV) is a unit of energy, but is not an SI unit . It is a commonly used unit of energy within physics, widely used in solid state , atomic , nuclear and particle physics, and high-energy astrophysics . It

767-403: A wavelength of 532 nm (green light) would have an energy of approximately 2.33 eV . Similarly, 1 eV would correspond to an infrared photon of wavelength 1240 nm or frequency 241.8 THz . In a low-energy nuclear scattering experiment, it is conventional to refer to the nuclear recoil energy in units of eVr, keVr, etc. This distinguishes the nuclear recoil energy from

826-399: Is a Pythagorean equation . When a relatively high energy is applied to a particle with relatively low rest mass , it can be approximated as E ≃ p {\displaystyle E\simeq p} in high-energy physics such that an applied energy with expressed in the unit eV conveniently results in a numerically approximately equivalent change of momentum when expressed with

885-461: Is an SI unit. In the fields of physics in which the electronvolt is used, other quantities are typically measured using units derived from the electronvolt as a product with fundamental constants of importance in the theory are often used. By mass–energy equivalence , the electronvolt corresponds to a unit of mass . It is common in particle physics , where units of mass and energy are often interchanged, to express mass in units of eV/ c , where c

944-438: Is called a hydrodynamic test, or hydrotest. Standard practice is to take a single stop-action snapshot of the weapon mockup's interior as the molten components rush inward at thousands of meters per second. X-rays that can penetrate the heavy metal in a weapon mockup are made with an electron accelerator . An electron beam moving at near the speed of light is smashed into a tungsten target. The electrons are yanked off course by

1003-436: Is commonly used with SI prefixes milli- (10 ), kilo- (10 ), mega- (10 ), giga- (10 ), tera- (10 ), peta- (10 ) or exa- (10 ), the respective symbols being meV, keV, MeV, GeV, TeV, PeV and EeV. The SI unit of energy is the joule (J). In some older documents, and in the name Bevatron , the symbol BeV is used, where the B stands for billion . The symbol BeV is therefore equivalent to GeV , though neither

1062-794: Is convenient to use the electronvolt to express temperature. The electronvolt is divided by the Boltzmann constant to convert to the Kelvin scale : 1 e V / k B = 1.602   176   634 × 10 − 19  J 1.380   649 × 10 − 23  J/K = 11   604.518   12  K , {\displaystyle {1\,\mathrm {eV} /k_{\text{B}}}={1.602\ 176\ 634\times 10^{-19}{\text{ J}} \over 1.380\ 649\times 10^{-23}{\text{ J/K}}}=11\ 604.518\ 12{\text{ K}},} where k B

1121-409: Is designed to involve the public and gather the best available information in a single place so that decision makers can be fully informed when they make their choices. This is the process of EIS Environmental Impact Statement Often, the agencies responsible for preparing an EA or EIS do not compile the document directly, but outsource this work to private-sector consulting firms with expertise in

1180-976: Is selected in the Record of Decision. For example, the "No Action Alternative" was selected for the I-69/Trans-Texas Corridor Tier-I Environmental Impact Statement. In that Record of Decision, the Texas Department of Transportation opted not to proceed with building its portion of I-69 as one of the Trans-Texas Corridors to be built as a new-terrain route (the Trans-Texas Corridor concept was ultimately scrapped entirely), but instead decided to proceed with converting existing US and state routes to I-69 by upgrading those roads to interstate standards. The NEPA process

1239-441: Is the Boltzmann constant . The k B is assumed when using the electronvolt to express temperature, for example, a typical magnetic confinement fusion plasma is 15 keV (kiloelectronvolt), which is equal to 174 MK (megakelvin). As an approximation: k B T is about 0.025 eV (≈ ⁠ 290 K / 11604 K/eV ⁠ ) at a temperature of 20 °C . The energy E , frequency ν , and wavelength λ of

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1298-663: Is the Planck constant , c is the speed of light . This reduces to E = 4.135   667   696 × 10 − 15 e V / H z × ν = 1   239.841   98 e V ⋅ n m λ . {\displaystyle {\begin{aligned}E&=4.135\ 667\ 696\times 10^{-15}\;\mathrm {eV/Hz} \times \nu \\[4pt]&={\frac {1\ 239.841\ 98\;\mathrm {eV{\cdot }nm} }{\lambda }}.\end{aligned}}} A photon with

1357-901: Is the speed of light in vacuum (from E = mc ). It is common to informally express mass in terms of eV as a unit of mass , effectively using a system of natural units with c set to 1. The kilogram equivalent of 1 eV/ c is: 1 eV / c 2 = ( 1.602   176   634 × 10 − 19 C ) × 1 V ( 299   792   458 m / s ) 2 = 1.782   661   92 × 10 − 36 kg . {\displaystyle 1\;{\text{eV}}/c^{2}={\frac {(1.602\ 176\ 634\times 10^{-19}\,{\text{C}})\times 1\,{\text{V}}}{(299\ 792\ 458\;\mathrm {m/s} )^{2}}}=1.782\ 661\ 92\times 10^{-36}\;{\text{kg}}.} For example, an electron and

1416-401: Is to help key decisionmakers and stakeholders balance the need to implement an action with its impacts on the surrounding human and natural environment, and provide opportunities for mitigating those impacts while keeping the cost and schedule for implementing the action under control. However, many activities require various federal permits to comply with other environmental legislation, such as

1475-864: The Clean Air Act , the Clean Water Act , Endangered Species Act and Section 4(f) of the Federal Highway Act to name a few. Similarly, many states and local jurisdictions have enacted environmental laws and ordinances, requiring additional state and local permits before the action can proceed. Obtaining these permits typically requires the lead agency to implement the Least Environmentally Damaging Practicable Alternative (LEDPA) to comply with federal, state, and local environmental laws that are ancillary to NEPA. In some instances,

1534-531: The Interstate 11 corridor in Nevada and Arizona are being studied through a two-tiered process By requiring agencies to complete an EIS, the act encourages them to consider the environmental costs of a project and introduces new information into the decision-making process. The NEPA has increased the influence of environmental analysts and agencies in the federal government by increasing their involvement in

1593-488: The United States Department of Energy . 35°50′02″N 106°18′09″W  /  35.83389°N 106.30250°W  / 35.83389; -106.30250 Environmental Impact Statement An environmental impact statement ( EIS ), under United States environmental law , is a document required by the 1969 National Environmental Policy Act (NEPA) for certain actions "significantly affecting

1652-410: The mean lifetime τ of an unstable particle (in seconds) in terms of its decay width Γ (in eV) via Γ = ħ / τ . For example, the B meson has a lifetime of 1.530(9)  picoseconds , mean decay length is cτ = 459.7 μm , or a decay width of 4.302(25) × 10  eV . Conversely, the tiny meson mass differences responsible for meson oscillations are often expressed in

1711-483: The "electron equivalent" recoil energy (eVee, keVee, etc.) measured by scintillation light. For example, the yield of a phototube is measured in phe/keVee ( photoelectrons per keV electron-equivalent energy). The relationship between eV, eVr, and eVee depends on the medium the scattering takes place in, and must be established empirically for each material. One mole of particles given 1 eV of energy each has approximately 96.5 kJ of energy – this corresponds to

1770-529: The ROD is issued, the lead agency will often coordinate with stakeholders at all levels, and resolve any conflicts to the greatest extent possible during the EIS process. Proceeding in this fashion helps avoid interagency conflicts and potential lawsuits after the lead agency reaches its decision. On exceptionally large projects, especially proposed highway , railroad , and utility corridors that cross long distances,

1829-425: The action may or may not cause a significant impact, the agency can first prepare a smaller, shorter document called an Environmental Assessment (EA). The finding of the EA determines whether an EIS is required. If the EA indicates that no significant impact is likely, then the agency can release a finding of no significant impact (FONSI) and carry on with the proposed action. Otherwise, the agency must then conduct

Dual-Axis Radiographic Hydrodynamic Test Facility - Misplaced Pages Continue

1888-497: The actors involved in environmental decisions, including government officials, private businesses, and citizens. In particular, an EIS acts as an enforcement mechanism to ensure that the federal government adheres to the goals and policies outlined in the NEPA. An EIS should be created in a timely manner as soon as the agency is planning development or is presented with a proposal for development. The statement should use an interdisciplinary approach so that it accurately assesses both

1947-547: The approved Tier I area is further broken down into subareas, and a Tier II EIS is then prepared for each subarea, that identifies the exact location of where the proposed action will take place. The preparation of Tier II EISs for each subarea proceeds at its own pace, independent from the other subareas within the Tier I area. For example, parts of the proposed Interstate 69 extension in Indiana and Texas , as well as portions of

2006-876: The conversion to MKS system of units can be achieved by: p = 1 GeV / c = ( 1 × 10 9 ) × ( 1.602   176   634 × 10 − 19 C ) × ( 1 V ) 2.99   792   458 × 10 8 m / s = 5.344   286 × 10 − 19 kg ⋅ m / s . {\displaystyle p=1\;{\text{GeV}}/c={\frac {(1\times 10^{9})\times (1.602\ 176\ 634\times 10^{-19}\;{\text{C}})\times (1\;{\text{V}})}{2.99\ 792\ 458\times 10^{8}\;{\text{m}}/{\text{s}}}}=5.344\ 286\times 10^{-19}\;{\text{kg}}{\cdot }{\text{m}}/{\text{s}}.} In particle physics ,

2065-435: The development process. Because an EIS requires expert skill and knowledge, agencies must hire environmental analysts. Unlike agencies who may have other priorities, analysts are often sympathetic to environmental issues. In addition, this feature introduces scientific procedures into the political process. The differences that exist between science and politics limit the accuracy of an EIS. Although analysts are members of

2124-414: The electronvolt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences, because a particle with electric charge q gains an energy E = qV after passing through a voltage of V . An electronvolt is the amount of energy gained or lost by a single electron when it moves through an electric potential difference of one volt . Hence, it has

2183-434: The environmental assessment process. The public does not realize that the process is only meant to gather information relevant to the decision. Even if the statement predicts negative impacts of the project, decision makers can still proceed with the proposal. KeV In physics , an electronvolt (symbol eV ), also written electron-volt and electron volt , is the measure of an amount of kinetic energy gained by

2242-408: The facility became completely operational. During a weapon's crucial triggering phase, explosive charges that surround the nuclear fuel are detonated at multiple points. The result is a shock wave that moves inward ( implosion ) at supersonic speeds, compressing the fuel to higher and higher density. Implosion ends when the fuel reaches a supercritical density, the density at which nuclear reactions in

2301-424: The fuel build up an uncontainable amount of energy, which is then released in a massive explosion. To make the mockup non-nuclear, a heavy metal surrogate (such as depleted uranium or lead ) stands in for the nuclear fuel, but all other components can be exact replicas. Sub-critical masses of plutonium may also be used. Under such extreme implosion forces materials tend to behave like fluids, so this mock implosion

2360-456: The high-voltage plate and the oil-insulated magnetic cores and at sites where metal, high-voltage insulator, and vacuum meet inside the cells. After much analysis, the design error was tracked to faulty equipment used when doing voltage calibrations. An extensive design overhaul and rebuild was required, which was completed in 2008. The project was initially expected to cost $ 30 million in 1988, but costs ultimately rose to $ 350 million by 2008 when

2419-404: The instant of firing, each generator discharges its power, creating a pulse of electric current through its induction cell, which in turn creates a large voltage difference across the gap separating that cell from its neighbor. The electron beam-pulse travels through the central bore of the cells, receiving a 200 keV energy kick each time it passes through a gap. One of the problems was designing

Dual-Axis Radiographic Hydrodynamic Test Facility - Misplaced Pages Continue

2478-660: The laboratory produce an Environmental Impact Statement for its construction and operation. Activists argued that DARHT is in violation of the Comprehensive Test Ban Treaty and potentially the Nuclear Non-Proliferation Treaty , though the lab and the DOE reject this view. When completed in 1999, the first-axis accelerator produced a 60ns electron pulse with a current of 2 kA and an energy of 20 MeV focused to 1mm diameter spot on

2537-400: The lead agency may use a two-tiered process prior to implementing the proposed action. In such cases, the Tier I EIS would analyze the potential socio-environmental impacts along a general corridor, but would not identify the exact location of where the action would occur. A Tier I ROD would be issued approving the general area where the action would be implemented. Following the Tier I ROD,

2596-404: The mass of a proton. To convert to electronvolt mass-equivalent, use the formula: By dividing a particle's kinetic energy in electronvolts by the fundamental constant c (the speed of light), one can describe the particle's momentum in units of eV/ c . In natural units in which the fundamental velocity constant c is numerically 1, the c may be informally be omitted to express momentum using

2655-985: The more convenient inverse picoseconds. Energy in electronvolts is sometimes expressed through the wavelength of light with photons of the same energy: 1 eV h c = 1.602   176   634 × 10 − 19 J ( 2.99   792   458 × 10 11 mm / s ) × ( 6.62   607   015 × 10 − 34 J ⋅ s ) ≈ 806.55439 mm − 1 . {\displaystyle {\frac {1\;{\text{eV}}}{hc}}={\frac {1.602\ 176\ 634\times 10^{-19}\;{\text{J}}}{(2.99\ 792\ 458\times 10^{11}\;{\text{mm}}/{\text{s}})\times (6.62\ 607\ 015\times 10^{-34}\;{\text{J}}{\cdot }{\text{s}})}}\thickapprox 806.55439\;{\text{mm}}^{-1}.} In certain fields, such as plasma physics , it

2714-503: The new induction cores to fit in the confines of the previous facility. The design team had to replace the ferrite used in the first axis cores with " metglas "—paper-thin ribbons of amorphous iron tape. The maximum magnetic field strength (saturation point) in metglas is five times higher than in ferrite. The magnetic tape was insulated by thin layers of mylar and wound up into a roll of 20,000 turns to make mammoth six-foot-diameter cores, each four inches wide and weighing more than one and

2773-402: The physical and social impacts of the proposed development. In many instances an action may be deemed subject to NEPA's EIS requirement even though the action is not specifically sponsored by a federal agency. These factors may include actions that receive federal funding, federal licensing or authorization, or that are subject to federal control. Not all federal actions require a full EIS. If

2832-612: The preparation of an EA or EIS. An example of the latter is when the Federal Highway Administration issued a CATEX to construct the replacement bridge in the wake of the I-35W Mississippi River Bridge Collapse . NEPA does not prohibit the federal government or its licensees/permittees from harming the environment, instead it requires that the prospective impacts be understood and disclosed in advance. The intent of NEPA

2891-412: The proposed action and its anticipated effects on the environment. Because of the intense level of detail required in analyzing the alternatives presented in an EIS or EA, such documents may take years or even decades to compile, and often compose of multiple volumes that can be thousands to tens of thousands of pages in length. To avoid potential conflicts in securing required permits and approvals after

2950-413: The quality of the human environment". An EIS is a tool for decision making. It describes the positive and negative environmental effects of a proposed action, and it usually also lists one or more alternative actions that may be chosen instead of the action described in the EIS. One of the primary authors of the act is Lynton K. Caldwell . Preliminary versions of these documents are officially known as

3009-536: The range of alternatives presented for study. The No Action Alternative identifies the expected environmental impacts in the future if existing conditions were left as is with no action taken by the lead agency. Analysis of the No Action Alternative is used to establish a baseline upon which to compare the proposed "Action" alternatives. Contrary to popular belief, the "No Action Alternative" doesn't necessarily mean that nothing will occur if that option

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3068-467: The result of NEPA analysis leads to abandonment or cancellation of the proposed action, particularly when the "No Action" alternative ends up being the LEDPA. An EIS typically has four sections: While not required in the EIS, the following subjects may be included as part of the EIS or as separate documents based on agency policy. Every EIS is required to analyze a No Action Alternative , in addition to

3127-431: The scientific community, they are affected by the political atmosphere. Analysts do not have the luxury of an unlimited time for research. They are also affected by the different motives behind the research of the EIS and by different perspectives of what constitutes a good analysis. In addition, government officials do not want to reveal an environmental problem from within their own agency. Citizens often misunderstand

3186-479: The second axis (initially to be a twin of the first) in 1997. This plan was changed when the Department of Energy decided it wanted the second axis to deliver not one view of the implosion, but a series of views in rapid succession. Construction was halted between 1995 and 1996 due to lawsuits by Los Alamos Study Group and Concerned Citizens for Nuclear Safety, two anti-nuclear weapons organizations demanding that

3245-442: The strong electrostatic pull of the positively charged nuclei in the tungsten atoms, and their sudden change in direction causes them to give off energy in the form of high-energy x-rays in a process called bremsstrahlung . Scientists already knew how to use a short burst (pulse) of high-energy electrons (rather than a continuous beam) to make a short pulse of high-energy x-rays recorded on conventional x-Ray films. The new challenge

3304-427: The target - the smallest spot size and shortest pulse length ever achieved at that intensity. As a result, image quality was about three times higher than at Livermore's FXR facility. The second machine (second axis) is more complicated and, when first completed in 2003, was found to be unusable due to electrical breakdown. The origin of the electrical breakdown turned out to be unexpectedly high electric fields between

3363-441: The unit electronvolt. The energy–momentum relation E 2 = p 2 c 2 + m 0 2 c 4 {\displaystyle E^{2}=p^{2}c^{2}+m_{0}^{2}c^{4}} in natural units (with c = 1 {\displaystyle c=1} ) E 2 = p 2 + m 0 2 {\displaystyle E^{2}=p^{2}+m_{0}^{2}}

3422-404: The unit eV/ c . The dimension of momentum is T L M . The dimension of energy is T L M . Dividing a unit of energy (such as eV) by a fundamental constant (such as the speed of light) that has the dimension of velocity ( T L ) facilitates the required conversion for using a unit of energy to quantify momentum. For example, if the momentum p of an electron is 1 GeV/ c , then

3481-467: Was for the accelerator to deliver a very large number of electrons in an extremely powerful pulse to generate an x-ray flash that can penetrate the mockup during the ultra-dense implosion. Specifications call for a pulse width of 60 billionths of a second. Each electron accelerator consists of a long row of doughnut-shaped magnetic induction cells, each connected to a high-voltage generator. There are 74 in total in each accelerator but not all may be used. At

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