237 research outputs found
Giant thermoemf in multiterminal superconductor/normal metal mesoscopic structures
We considered a mesoscopic superconductor/normal metal (S/N) structure in
which the N reservoirs are maintained at different temperatures. It is shown
that in the absence of current between the N reservoirs a voltage difference
arises between the superconducting and normal conductors. The voltage
oscillates with increasing phase difference between the
superconductors, and its magnitude does not depend on the small parameter
Comment: Resubmited, some changes to Text and Figure
THE EFFECTS OF FIELD EMITTED ELECTRONS ON RF SURFACE
The ever-growing demand for higher RF gradients has
considerably increased the risk of breakdown in
accelerating structures. Field emission is the most
common form of RF breakdown that generates free
electrons capable of inflicting irreversible damages on the
RF surface. This paper presents a systematic experimental
and simulation programme to understand possible sources
and their influence on RF cavity operatio
Radiological Risks of Neutron Interrogation of Food
In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different
scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered.
There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; Activity, Ingestion
Dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation.
Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that 24Na production is the dominant threat which motivated the search for 23(n;\gamma)24Na in highly salted foods. We show that 42K can be more significant than 24Na in low
salt foods such as Bananas and Potatoes
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Thorium Energy Futures
The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice
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