Author: Yu. N. PokotilovskijPublisher:
ISBN:
Category :
Languages : en
Pages : 22
Book Description
Optimization Study of Ultracold Neutron Sources at TRIGA Reactors Using MCNP
Author: Yu. N. PokotilovskijInvestigation of a Superthermal Ultracold Neutron Source Based on a Solid Deuterium Converter for the TRIGA Mainz Reactor
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Research in fundamental physics with the free neutron is one of the key tools for testing the Standard Model at low energies. Most prominent goals in this field are the search for a neutron electric dipole moment (EDM) and the measurement of the neutron lifetime. Significant improvements of the experimental performance using ultracold neutrons (UCN) require reduction of both systematic and statistical errors.rnThe development and construction of new UCN sources based on the superthermal concept is therefore an important step for the success of future fundamental physics with ultracold neutrons. rnSignificant enhancement of today available UCN densities strongly correlates with an efficient use of an UCN converter material. The UCN converter here is to be understood as a medium which reduces the velocity of cold neutrons (CN, velocity of about 600 m/s) to the velocity of UCN (velocity of about 6 m/s).rnSeveral big research centers around the world are presently planning or constructing new superthermal UCN sources, which are mainly based on the use of either solid deuterium or superfluid helium as UCN converter.rnThanks to the idea of Yu. Pokotilovsky, there exists the opportunity to build competitive UCN sources also at small research reactors of the TRIGA type. Of course these smaller facilities don't promise high UCN densities of several 1000 UCN/cm3, but they are able to provide densities around 100 UCN/cm3 for experiments.rnIn the context of this thesis, it was possible to demonstrate succesfully the feasibility of a superthermal UCN source at the tangential beamport C of the research reactor TRIGA Mainz. Based on a prototype for the future UCN source at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII) in munich, which was planned and built in collaboration with the Technical University of Munich, further investigations and improvements were done and are presented in this thesis. rnIn parallel, a second UCN source for the radial beamport D was designed.
Simulation of cold neutron production using ordinary and deuterated cryogenic organic moderators
Author: Martin Luc NisetExperimental Study of Ultracold Neutron Localization and Sub-Barrier Penetration
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
Free ultracold neutrons (UCN) may be stored in magnetic or material''bottles'' by total internal reflection and via the small neutron magnetic dipole moment. However, the storage time for these UCN is much smaller than predicted by theory and cannot be attributed to normal radioactive decay of the particle. One explanation for this short storage time has been so-called ''states of localization'' of sub-barrier UCN at inhomogeneities in the reflection materials. This theory assumes enhanced absorption and upscattering by hydrogen impurities and higher than expected penetration of the sub-barrier UCN in foil materials. The original NEER-supported project proposed to investigate UCN using a LANL developed source. Unfortunately, this source was placed in standby at the earliest stage of the project due to funding redirection at LANL. Ultimately, the source was decommissioned as LANL investigated other methods of UCN production. Attempts to derive an UCN beam from the UT TRIGA reactor were unsuccessful and not directly supported by the NEER project.
Cold Neutron Sources: Practical Considerations and Modern Research
Author: International Atomic Energy AgencyPublisher: International Atomic Energy Agency
ISBN: 9789201394231
Category : Technology & Engineering
Languages : en
Pages : 0
Book Description
This Safety Report provides guidance, targeted towards States newly embarking upon a nuclear power plant programme, on the licensing process and associated procedures needed during for the construction, commissioning and operation stages of a nuclear power plant, so that the applicant complies with national regulations in line with the internationally recognized safety principles and requirements throughout these stages. The publication elaborates on the generic guidance provided in IAEA Safety Standards Series No. SSG-12, Licensing Process for Nuclear Installations, and gives supplementary practical guidance for nuclear power plants.
Design and Construction of the Ultracold Neutron Source at the NC State PULSTAR Research Reactor
Author: Grant R. PalmquistFeasibility Study for a Pulsed Cold Neutron Source at the University of Arizona Triga Reactor (MS).
Author: Malek Ahmad ChatilaPublisher:
ISBN:
Category : Nuclear and energy engineering
Languages : en
Pages : 0
Book Description
Cholodnye i Ulʹtracholodnye Nejtronnye Istočniki Na Reaktore VVR-M
Author: Investigation of a Superthermal Ultracold Neutron Source Based on a Solid Deuterium Converter for the TRIGA Mainz Reactor
Author: Thorsten LauerUsing MCNP for fusion neutronics
Author: Frej WasastjernaPublisher:
ISBN: 9789513871291
Category : Monte Carlo method
Languages : en
Pages : 68
Book Description
Any fusion reactor using tritium-deuterium fusion will be a prolific source of 14 MeV neutrons. In fact, 80% of the fusion energy will be carried away by these neutrons. Thus it is essential to calculate what will happen to them, so that such quantities as the tritium breeding ratio, the neutron wall loading, heat deposition, various kinds of material damage and biological dose rates can be determined. Monte Carlo programs, in particular the widely-used MCNP, are the preferred tools for this. The International Fusion Materials Irradiation Facility (IFMIF), intended to test materials in intense neutron fields with a spectrum similar to that prevailing in fusion reactors, also requires neutronics calculations, with similar methods. In some cases these calculations can be very difficult. In particular shielding calculations - such as those needed to determine the heating of the superconducting field coils of ITER or the dose rate, during operation or after shutdown, outside ITER or in the space above the test cell of IFMIF - are very challenging. The thick shielding reduces the neutron flux by many orders of magnitude, so that analog calculations are impracticable and heavy variance reduction is needed, mainly importances or weight windows. On the other hand, the shields contain penetrations through which neutrons may stream. If the importances are much higher or the weight windows much lower at the outer end of such a penetration than at the inner end, this may lead to an excessive proliferation of tracks, which may even make the calculation break down. This dissertation describes the author's work in fusion neutronics, with the main emphasis on attempts to develop improved methods of performing such calculations. Two main approaches are described: trying to determine nearoptimal importances or weight windows, and testing the "tally source" method suggested by John Hendricks as a way of biasing the neutron flux in angle.