Detection Of Nuclear Weapons And Materials

(1) How Does Detection Work?; Current Detection Technol.; (2) Advanced Technol.: Nanocomposite Scintillators; GADRAS: Gamma-Ray Spectrum Analysis Application Using Multiple Algorithms; Computer Modeling to Evaluate Detection Capability; L-3 CAARS: Low-Risk Dual-Energy Radiography System; SAIC CAARS: Higher-Risk, Higher-Benefit Dual-Energy Radiography System; AS&E CAARS: Using Backscattered X-Rays to Detect Dense Material; Muon Tomography; Analyzing a Nuclear Weapon with Nuclear Resonance Fluorescence; Detecting SNM at a Distance; (3) Signatures of Plutonium, Highly Enriched Uranium, and Nuclear Weapons; Detecting Signatures of a Nuclear Weapon or SNM; Evasion of Detection Technol. Illus.

Detection of nuclear weapons and special nuclear material (SNM, certain types of uranium and plutonium) is crucial to thwarting nuclear proliferation and terrorism and to securing weapons and materials worldwide. Congress has funded a portfolio of detection R&D and acquisition programs, and has mandated inspection at foreign ports of all U.S.-bound cargo containers using two types of detection equipment. Nuclear weapons contain SNM, which produces unique or suspect signatures that can be detected. It emits radiation, notably gamma rays (high-energy photons) and neutrons. SNM is very dense, so it produces a bright image on a radiograph (a picture like a medical x-ray) when x- rays or gamma rays are beamed through a container in which it is hidden. Using lead or other shielding to attenuate gamma rays would make this image larger. Nuclear weapons produce detectable signatures, such as radiation generated by or a noticeable image on a radiograph. Other detection techniques are also available. Nine technologies illustrate the detection portfolio: (1) A new scintillator material to improve detector performance and lower cost. (2) GADRAS, an application using multiple algorithms to determine the materials in a container by analyzing gamma-ray spectra. If materials are the eyes and ears of detectors, ...

This report seeks to help Congress understand nuclear detection technology. It discusses the science of detecting nuclear weapons and materials, describes nine advanced U.S. technologies selected to illustrate the range of projects in the pipeline, and offers observations for Congress.

Terrorist use of radioactive nuclear materials is a serious threat for mass destruction or disruption of civil and military activities. Most worrisome is the use of nuclear devices to cause massive casualties to people and damage to structures. Fortunately, the procurement of adequate material and the engineering design, construction, and transportation and triggering of a nuclear weapon are all difficult problems for terrorist organizations. More likely is a device that combines radioactive materials with conventional explosives to make a radiological dispersion device, commonly called a "dirty bomb". The procurement of nuclear materials for this purpose, the construction of the bomb and its use are all easier than for a nuclear weapon. Fortunately, the effects from the use of a radiological weapon would be much smaller than from a nuclear device, although they could still be very disruptive. Thus, it is important to detect the transport of nuclear weapons and radiological dispersion devices and the materials for their construction. These materials emit gamma rays or neutrons, which can be detected to show the presence and amounts of such materials.

In this study, CISAC tackles the technical dimensions of a longstanding controversy: To what extent could existing and plausibly attainable measures for transparency and monitoring make possible the verification of all nuclear weaponsâ€"strategic and nonstrategic, deployed and nondeployedâ€"plus the nuclear-explosive components and materials that are their essential ingredients? The committee's assessment of the technical and organizational possibilities suggests a more optimistic conclusion than most of those concerned with these issues might have expected.

Considers technical problems of a nuclear weapons test ban, including the type of research and development programs necessary for a workable system of detection and inspection.