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A wide variability exists among commercial radiation detection instruments used to measure exposure rate or ambient dose equivalent rate. These instruments are used to measure both the radiation background and the radiation field produced by radioactive sources that are used to test other types of radiation detection systems against different consensus document standards. Most radiation fields specified in the ANSI standard are quite low, ranging from 0.05 Sv/h to 0.5 Sv/h above background. Due to the radiation fields being so low in intensity, the uncertainty of the measurements made with these instruments can be potentially quite large. As a result of these large uncertainties, it is possible that the response of the various parameters being tested by the standards (e.g., alarm indication, radionuclide identification) will be dependent on the specific radiation detector employed by the testing laboratory. In this work, we used two different methods to set the radiation fields to analyze the differences that can be expected. One method is based on measurements performed with a high pressure ion chamber while the second method is based on calculating the radiation fields from a known source activity using a point source estimate. The sources of uncertainties in both methods are identified and are reflected in the differences that can be expected in setting the radiation fields. In order to achieve consistency across different testing laboratories in setting radiation fields, we provide insight to what are the most relevant factors that affect the determination of the field using either one of the two methods.

Detection. --- Homeland security. --- Radiation.

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By almost any measure, the United States is the most powerful nation in the history of civilization. Our resources are immense. But they are not limitless. Today national security requires agility to stay a step ahead of threats that can rapidly appear and change, and endurance to deal with challengers that are unlikely to disappear anytime soon. The central question for U.S. leaders today is how can we retain our strategic advantage and continue to set the agenda for world affairs?

National security --- Homeland defense --- Homeland security

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In this timely edited volume of papers, experts on international security assess, and put in context, the supposed dangers to American security.

National security --- Homeland defense --- Homeland security

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The Aspin-Brown Commission of 1995-1996, led by former U.S. Defense Secretaries Les Aspin and Harold Brown, was a landmark inquiry into the activities of America's secret agencies. The purpose of the commission was to help the Central Intelligence Agency and other organizations in the U.S. intelligence community adapt to the quite different world that had emerged after the end of the Cold War in 1991. In The Threat on the Horizon, eminent national security scholar Loch K. Johnson, who served as Aspin's assistant, offers a comprehensive insider's account of this inquiry. Based on a close siftin

Intelligence service --- National security --- Homeland defense --- Homeland security

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How can the United States avoid a future surprise attack on the scale of 9/11 or Pearl Harbor, in an era when such devastating attacks can come not only from nation states, but also from terrorist groups or cyber enemies? Intelligence and Surprise Attack examines why surprise attacks often succeed even though, in most cases, warnings had been available beforehand. Erik J. Dahl challenges the conventional wisdom about intelligence failure, which holds that attacks succeed because important warnings get lost amid noise or because intelligence officials lack the imagination and collaboration to

National security --- Intelligence service --- Homeland defense --- Homeland security