580 research outputs found

    Results from the Harvard, Pennsylvania, Wisconsin-FNAL experiment

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    A brief survey is given of the data on muonless events/neutral currents accumulated in the experiment. (0 refs)

    Heavy-ion accelerators for inertial confinement fusion

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    Two concepts have been applied to the classical problem of accelerators for the ignition of indirectly driven inertial fusion. The first is the use of non-Liouvillian stacking based on photoionisation of a singly charged ion beam. A special FEL appears the most suited device to generate the appropriate light beam intensity at the required wavelength. The second is based on the use of a large number of (>1000) beamlets-or "beam straws‚ÄĚ-all focussed by an appropriate magnetic structure and concentrated on the same spot on the pellet. The use of a large number of beams-each with a relatively low-current density-elegantly circumvents the problems of space charge, making use of the non-Liouvillian nature of the stopping power of the material of the pellet. The present conceptual design is based on a low-current (i ‚Čą 50 mA) heavy-ion beam accelerated with a standard LINAC structure and accumulated in a stack of rings with the help of photoionisation. Beams are then extracted simultaneously from all the rings and further subdivided with the help of a switchyard of alternate paths separating and synchronising the many bunches from each ring before they hit the pellet. Single beam straws carry a reasonable number of ions: Beams and technology are directly relatable to the ones presently employed, for instance, at the CERN-PS. Space-charge-dominated conditions arise only during the last few turns before extraction and in the beam transport channel to the reaction chamber. In a practical example, we aim at a peak power of 500 TW delivered to the pellet for a duration of 10-15 ns. High-energy (10 GeV) beam straws of Ba doubly ionised ions are concentrated on several (four) focal spots of a radius of about 1 mm. The power density deposited on these tiny cylindrical absorbers inside a hermetic "hohlraum‚ÄĚ is about 2.5 √ó 1016 w/g. These conditions are believed to be optimal for X-ray conversion, i.e., with an estimated conversion efficiency of about 90

    A tentative programme towards a full scale energy amplifier

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    We present a proposal of a full scale demonstration plant of the Energy Amplifier (EA), following the conceptual design of Ref. [1]. Unlike the presently on going CERN experiments, reaction rates will be sufficiently massive to permit demonstrating the practical feasibility of energy generation on an industrial scale and to tackle the complete family chains of [1] the breeding process in Thorium fuel, [2] the burning of the self-generated Actinides, [3] the Plutonium (higher Actinides) burning of spent fuel from ordinary Reactors and [4] Fuel reprocessing/regeneration. The accelerator must provide a beam power which is commensurate to the rate of transformations which are sought. No existing accelerator can meet such a performance and a dedicated facility must be built. We describe an alternative based on the superconducting cavities (SC) now in standard use at the LEP e+‚ąíe‚ąíe^+-e^- collider which is scheduled to terminate its operation by year 200 After this time, with reasonable modifications, the fully operational and tested LEP SC-system offers the formidable opportunity of being redeployed elsewhere, accelerating a large (30 mA) proton current to at least 1 GeV required by the full scal (1500 MWthermal)MW_thermal) EA operated at the conservative multiplication coefficient, k = 0.95. Due to the high efficiency of the SCs, even at such small k-value typical for a 3repository2 the fraction of electric power for the accelerator is about 10%. The LEP-SC system is now fully industrialised and it may constitute a well tested and sound basis for the further development of the commercial series. Heat produced by the EA is considerable (4,650 Tons coal/day or 22,70 and justifies our design which is very close to the one of Ref. [1] and to the one of a commercial prototype. At first, one can assume that heat is simply thrown away. Later on, local commercialisation of such energy source is worth considering. T application is electricity generation

    Sterile neutrinos: the necessity for a 5 sigma definitive clarification

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    Several different experiments have hinted to the existence of "anomalies" in the neutrino sector, implying the possible presence of additional sterile neutrinos or of other options. A definitive experimental search, capable to clarify either in favour or against all these anomalies at the appropriate > 5 sigma level has been proposed by the ICARUS-NESSIE Collaboration. The technique is based on two innovative concepts, namely (1) a large mass Liquid Argon Time Projection Chamber (LAr-TPC) now in full operation at LNGS and (2) the search for spectral differences in two identical detectors at different distances along the (anti-)neutrino line(s).Comment: 7 pages, 4 figures, 1 tabl

    Fast neutron incineration in the energy amplifier as alternative to geologic storage: the case of Spain

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    In previous reports [1][2] we have presented the conceptual design of a fast neutron driven sub-critical device (Energy Amplifier) designed both for energy amplification (production) and for the incineration of unwanted ¬≥waste¬≤ from Nuclear Light Water Reactors (LWR). The latter scheme is here applied to the specific case of Spain, where 9 large LWR¬Ļs are presently in operation. It is shown that a cluster of 5 EA¬Ļs is a very effective and realistic solution to the elimination (in 37 years) of the present and foreseen (till 2029) LWR-Waste stockpiles of Spain, but with major improvements over Geologic Storage, since: (1) only a Low Level Waste (LLW) surface repository of reasonable size is ultimately required; (2) the large amount of energy stored in the trans-Uranics is recovered, amounting for each of the 37 years of incineration to a saving of about 8% of the present primary energy demand of Spain (100 MTep/y); (3) the slightly enriched (1.1%) Uranium, unburned by LWR¬Ļs, can be recovered for further use; (4)Trans-Uranic waste is transformed into fissile 233U,whichcanbeusedtomake+20{^233}U, which can be used to make +20% of LWR fuel without isotopic separation and (5) the capital cost of the complete facility, including reprocessing is convincingly lower than the one of the Geologic Storage. The volume of the ultimately Class A LLW can be further reduced by about an order of magnitude transmuting parasitically in the EA¬Ļs into stable nuclear species also the two most offending long-lived isotopes, {^99}Tcand and {^128}I.ThetotalLLWvolumeultimatelyrequired(601000m3)willthenberoughlyabout1. The total LLW volume ultimately required (60¬Ļ000 m3) will then be roughly about 1% of the present LLW storage in the USA and comparable to the present capacity of the now operational ¬≥El Cabril¬≤ in Spain (50¬Ļ000 m{^3}$). We conclude that EA-driven incineration when compared to direct Geological Disposal is environmentally more acceptable and economically more advantageous. Finally, no major technical barriers hinder its realisation
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