Development of a New Superfluid Helium Ultra-cold Neutron Source and a New Magnetic Trap for Neutron Lifetime Measurements PDF Download

Author: Kent Kwan Ho Leung
Publisher:
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Category :
Languages : en
Pages : 279

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Author:
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ISBN:
Category :
Languages : en
Pages : 4

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This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL) concerning the investigation of a new method for the experimental exploitation of ultra-cold neutrons. The production and storage of ultra cold neutrons in superfluid helium has been suggested as a tool for the production of high densities of ultra cold neutrons for fundamental nuclear physics as well as for sensitive measurements for condensed matter. A particular application of this technique has been suggested by Doyle and Lamoreaux that involves the trapping of neutrons in a magnetic field within the superfluid helium volume. Neutron decays within the trap volume are detected by the scintillation light produced in the liquid helium. A cryostat and magnetic trap have been constructed as well as a prototype light detection system. This system was installed on a cold neutron beam line at the NIST Cold Neutron Research Facility in the summer of 1997. Preliminary results indicate the detection of helium scintillation light from the detection vessel.

Author: Susan J Seestrom
Publisher: World Scientific
ISBN: 9814571687
Category : Science
Languages : en
Pages : 193

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There is a great interest in improving the limits on neutron lifetime to the level of a precision of 0.1 s. The neutron lifetime is both an important fundamental quantity as well as a parameter influencing important processes such as nucleosynthesis (Helium production in the early universe) and the rate of energy production in the Sun.Aiming to create a roadmap of R&D for a next generation neutron lifetime experiment that can be endorsed by the North American neutron community, the focus of the workshop was on experiments using traps that utilize ultracold neutrons and confinement by a combination of magnetic and/or gravitational interaction in order to avoid systematic uncertainties introduced by neutron interactions with material walls. The papers in this volume summarize the limitations of present experiments, the discussion of new experiments in planning stage, and the discussion of systematic effects that must be addressed to achieve a lifetime measurement at an accuracy of 0.1 second.Cover image courtesy of Elena Fernández, Los Alamos National Laboratory.

Author: Christopher Martin O'Shaughnessy
Publisher:
ISBN:
Category :
Languages : en
Pages : 161

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Publisher: DIANE Publishing
ISBN: 9781422328385
Category :
Languages : en
Pages : 6

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Category :
Languages : en
Pages : 7

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We present a conceptual design for an experiment to measure the neutron lifetime ((almost equal to)882 s) with an accuracy of 10−4. The lifetime will be measured by observing the decay rate of a sample of UCNs confined in vacuum in a magnetic trap. The UCN collaboration at LANL has developed a prototype ultra-cold neutron UCN source that is expected to produce a bottled UCN density of more than 100 UCN/cm3. The availability of such an intense source makes it possible to approach the measurement of the neutron lifetime in a new way. We argue below that it is possible to measure the neutron lifetime to 10−4 in a vacuum magnetic trap. The measurement involves no new technology beyond the expected UCN density. If even higher densities are available, the experiment can be made better and/or less expensive. We present the design and methodology for the measurement. The slow loss of neutrons that have stable orbits, but are not energetically trapped would produce a systematic error in the measurement. We discuss a new approach, chaotic cleaning, to the elimination of quasi-neutrons from the trap by breaking the rotational symmetry of the quadrupole trap. The neutron orbits take on a chaotic character and mode mixing causes the neutrons on the quasi-bound orbits to leave the trap.

Author:
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Languages : en
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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.

Author:
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Category : Chemistry
Languages : en
Pages : 232

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Category : Dissertations, Academic
Languages : en
Pages : 846

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Author: Beryl Bell
Publisher:
ISBN:
Category :
Languages : en
Pages :

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"This thesis addresses a collection of analyses and simulations done on behalf of the TRIUMF Ul-traCold Advanced Neutron (TUCAN) collaboration in order to contribute to the development ofthe new UltraCold Neutron (UCN) source in an effort to increase the precision on the measurementof the neutron Electric Dipole Moment (nEDM) to10−27ecm. Within this range a non-zero nEDMwould verify physics beyond the standard model. In order to produce UCN, TUCAN combinesaccelerator driven spallation with a superfluid helium cryostat.The first chapter details the physics background required to understand how the UCN source worksand how the required precision for the nEDM measurement will be achieved. Additionally, it willintroduce PENTrack, the Monte Carlo simulation software which has been developed specificallyfor UCN and nEDM simulations. The second chapter introduces the experimental setup at TRI-UMF, including the proton beamline developed for this UCN source, the prototype source cryostatdeveloped at the Research Center for Nuclear Physics (RCNP) of the University of Osaka, and thenEDM spectrometer which is still under development. Additionally, it will cover briefly the typesof UCN experiments performed at TRIUMF in 2018, which are the main focus of this thesis, aswell as the two types of UCN detectors and how they operate. Chapter 3 covers the analysis ofthe 2018 run relevant to this work. During this run the relative responses of two detectors weremeasured. Furthermore, the total accumulated proton beam intensity on target during the 2018run was extracted from the data, followed by a verification of the correspondence of the TorodialNon-Intercepting Monitor (TNIM) reading with the extracted beam intensity. Chapter 4 is an intro-duction of a potential future experiment to be performed at the TRIUMF source in order to measurethe energy spectrum of the UCN produced in the source using a gravity spectrometer. During thepreparation for this experiment it was found that there were significant differences in measuredand simulated storage lifetimes in the spectrometer. Reasons for this discrepancy are discussedand paths of investigation are presented. Chapter 5 concludes the above work and summarizes theresults of this thesis and the work to follow"--