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In this work we have studied the feasibility of photonuclear production of (47)Ca from (48)Ca for (47)Ca/(47)Sc generators. Photon flux distribution for electron beams of different energies incident on a tungsten converter was calculated using the MCNPX radiation transport code. The (47)Ca production rate dependence on electron beam energy was found and (47)Ca/(47)Sc yields were estimated for a 40MeV electron beam. It was shown that irradiating enriched targets with a 40MeV, 1mA beam will result in tens of MBq g(-1) (few mCi g(-1)) activity of (47)Sc. The results of the simulations were benchmarked by irradiating 22.5g of CaCl2 powder with a 39MeV electron beam incident on a tungsten converter. Measured (47)Ca/(47)Sc activities were found to be in very good agreement with the predictions.

The Lawrence Berkeley National Laboratory and Adelphi Technology Inc. have developed a series of high-yield neutron generators using the D-D reaction with an axial geometry. They operate with a single ion beam and can have a small origin size useful for immediate moderation and a high concentration of thermal neutrons. The generator uses RF induction discharge to efficiently ionize the deuterium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. These generators are open systems that can be actively pumped for a continuous supply of deuterium gas further increasing the generator's expected lifetime. Since the system is open, many of the components, including the target, can be easily replaced. Pulsed and continuous operation has been demonstrated. In either mode of operation these generators have been used for Prompt Gamma Neutron Activation Analysis (PGNAA) and neutron activation analysis (NAA). Carleton University and Heliocentric Technologies are developing an Elemental Analyzer based on this neutron source.

Given the threat of radiological and nuclear terrorism, it is imperative to understand and evaluate the security risk of radioactive sources. In this context, risk assessment is a function of threat, vulnerability, and consequences. Currently, no broad risk index exists for radiological facilities, such as healthcare centers and universities. This study aims to develop and demonstrate a methodology to compute a potential facility risk index (PFRI) based on a probable loss event (LE) and loss magnitude (LM) resulting from a radiological dispersal device (RDD) attack. The threat component of the PFRI is devised as a utility function weighing the threat group attributes and RDD radioactive material preference. The principles of probabilistic risk assessment and pathway analysis are implemented to account for RDD radioactive material theft probabilities in different attack scenarios. Locational hazards and nuclear security culture are measured as a function of radiological facility vulnerability for LE. The LM of the attack, in the form of loss of life and economic damage, is then estimated to construct the PFRI. The methodology is applied to a hypothetical healthcare facility with a single radioactive material asset. For this example, the PFRI resulted in a value of 2.0 (on a scale of 1–10), showing low risk to the facility. The development of the PFRI provides a risk analysis tool that may be useful in making decisions for radiological security improvements.

A standard product line of high yield neutron generators has been developed at Adelphi Technology Inc. The generators use the D-D fusion reaction and are driven by an ion beam supplied by a microwave ion source. Yields of up to 5×10 9 n/s have been achieved, which are comparable to those obtained using the more efficient D-T reaction. The microwave-driven plasma uses the electron cyclotron resonance (ECR) to produce a high plasma density for high current and high atomic ion species. These generators have an actively pumped vacuum system that allows operation at reduced pressure in the target chamber, increasing the overall system reliability. Variations of these generators have been produced to increase the yield and total flux available. Several of the generators have been enclosed in radiation shielding/moderator structures designed for customer specifications. These generators have been proven to be useful for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA) and fast neutron radiography. Pulsed and continuous operation has been demonstrated. Larger thermal neutron fluxes are expected to be obtained by multiple ion beams striking a central target that is filled with moderating material. Thus these generators make excellent fast, epithermal and thermal neutron sources for laboratories and industrial applications that require neutrons with safe operation, small footprint, low cost and small regulatory burden.