Radiation dispersal devices

The use of radiation dispersal devices, commonly referred to as dirty bombs, is particularly concerning for disaster planning and emergency preparedness personnel. An RDD is an explosive device designed to spread radioactive material without a nuclear explosion (Briggs Brinsfield, 2003). The initial blast from the explosion can kill or inflict mechanical trauma on those who are close in proximity to the explosion while the radioactive material is dispersed. Please refer to chapter 27, Radiological Incidents and Emergencies, for further information on decontamination, radiation sickness, and personal protective measures. 

Radiological Hazards. Adversaries and even terrorist could spread radioactive material in an effort to deny US forces access to key terrain, roads, and buildings. The use of radiation dispersal devices and destruction of local nuclear reactors by terrorists are examples of radiological threats. Other radiological hazards present during deployments may include improperly dumped waste and accidents involving radioactive commodities. 

Joint Pub 3-11 (Draft) covers the procedures to warn and report NBC releases including Releases Other Than Attack (ROTA). This information is not reproduced here since the publication is still under review. ROTAs include NBC releases due to damaged or destroyed storage bunkers, transport vehicles, storage or production facilities, ammunition supply sites, power plants, etc. It also includes the use of radiation dispersal devices. 

Cs / Soil Density Detector (MC-1) / Radiation Dispersal Devices ... 

RAMT - Radiological Advisory Medical Team. RDD - Radiation Dispersal Device. 

All spectrometers have the following basic units a source of electromagnetic radiation, a dispersion device, sample holder, optical devices for collimating and focusing, a detection device and a data readout or storage system. There are also a variety of ways in which these parts are assembled into the entire spectrometer. 

The drive of the dispersing device is synchronised with the x-axis of the recorder or fed directly to a computer, so that this indicates the wavelength of radiation reaching the detector. The signal from the detector is transmitted to the y-axis of the recorder or to a computer and this indicates how much radiation is absorbed by the sample at any particular wavelength. 

The energy source, the materials from which the dispersing device and the detector are constructed must be appropriate for the range of wavelength scanned and as transparent as possible to the radiation. For UV measurements, the cells and optieal components are typically made of quartz and ethanol, hexane, water or dioxan are usually chosen as solvents. 

Image Devices. Although he never assembled an actual TV-spectrometer, Margoshes was the first to recognize the potential of TV-type detectors in analytical atomic spectroscopy. In a series of reports (50,51,52) he speculated on the advantages of using an SEC tube [vide infra] to detect radiation dispersed by an echelle spectrograph. These reports and the recent availability of various solid-state array detectors have prompted numerous... 

Most spectroscopic measurements involve the use of an appropriate combination of source, dispersive device, and detector to analyze the absorption or emission spectrum of a sample. If only the wavelength or frequency of the radiation is measured, the resultant instrument is called a spectrometer. If the instrument provides a measure of the relative intensity associated with each wavelength, it is called a spectrophotometer, but this fine distinction is often ignored. Absorption spectra are often characterized by the transmittance Tat a given wavelength this is defined by... 

A radiological dispersal device (RDD) explodes, contaminating 10 square miles with radioactive cobalt (Co-60). The highest measured radiation level is about 10 meters from the site of the explosion and it reads about 150 mrem/hr. The average radiation dose through the affected area is 5 mrem/hr, and about 500,000 people live and work in this area. The device itself consisted of 1,000 pounds of explosive, set off near City Hall. 

The use of radioactive isotopes in industry is covered by government legislation. In the United States this is under OSHA (29 CFR 1910.1096), and in Canada it is governed by the Radiation Emitting Devices Act (R.S., 1985, c. R-1). Low levels of radiation may also be present in natural minerals. Care should be taken if these radioactive materials are concentrated or accumulated in the process or dispersed into the environment. 

The basic elements of any emission spectroscope are (1) a source that contains the substance to be studied and is capable of energizing that substance so that it can emit its characteristic radiation, (2) a dispersing device to resolve the emitted radiation into its component frequencies, and (3) a detector that can measure the intensity of the radiation at the various frequencies. The choice of devices for each of these elements depends on the region of the spectrum under investigation. 

A radiation threat, commonly referred to as a "dirty bomb" or "radiological dispersion device (RDD) , is the use of common explosives to spread radioactive materials over a targeted area. It is not a nuclear blast. The force of the explosion and radioactive contamination will be more localized. While the blast will be immediately obvious, the presence of radiation will not be clearly defined until trained personnel with specialized equipment are on the scene. As with any radiation, you want to try to limit exposure. 

Commercial infrared spectrometers operate either on the dispersive or, less frequently, the interferometric principles. In the dispersive instruments, a source of infrared radiation passes through a sample, is dispersed into its frequencies by a monochromator, and the relative intensities of individual frequencies measured by a detector are displayed on a stripchart recorder. Gratings, rather than prism monochromators, are used nowadays as dispersive devices in the IR region (Kemp, 1975). 

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